kth.sePublications
Change search
Refine search result
1234567 1 - 50 of 352
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Abburu, Sai Kausik
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Vehicle Conceptualisation, Compactness, and Subsystem Interaction: A network approach to design and analyse the complex interdependencies in vehicles2023Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The conventional approach to vehicle design is restrictive, limited, andbiased. This often leads to sub-optimal utilisation of vehicle capabilities and allocated resources and ultimately entails the repercussions of designing andlater on an using an inefficient vehicle. To overcome these limitations, it is important to gain a deeper understanding of the interaction effects at component,subsystem, and system level. In this thesis, the research is focused on identifying appropriate methods and developing robust models to facilitate the interaction analysis.

    To scrutinise and identify appropriate methods, criteria were developed.Initially, the Design Structure Matrix (DSM) and its variations were examined.While DSM proved to be fundamental for capturing interaction effects,it lacked the ability to answer questions about the structure and behaviour ofinteractions and to predict unintended effects. Therefore, network theory wasexplored as a complementary method to DSM which was capable of providing insights into interaction structures and identifying influential variables.

    Subsequently, two criteria were established to identify subsystems significant to interaction analysis: high connectivity to other subsystems and multidisciplinary composition. The traction motor was observed to satisfyboth criteria as it had higher connectivity with other subsystems and was composed of multiple disciplines. Therefore, a detailed model of an induction motor was developed to enable the interaction analysis.

    The induction motor model was integrated into a cross-scalar design tool.The tool employed a two-step process: translating operational parametersto motor inputs using Newtonian equations and deriving physical attributes,performance characteristics, and performance attributes of the motor. Comparing the obtained performance characteristics curve against existing studiesvalidated the model’s reliability and capabilities. The design tool demonstrated adaptability to different drive cycles and the ability to modify motor performance without affecting operational parameters. Thus validating the capability of the design tool to capture cross-scalar and intra-subsystem interaction effects. To examine inter-subsystem interaction, a thermal model of an inverter was developed, capturing temperature variations in the power electronics based on motor inputs. The design tool successfully captured interaction effects between motor and inverter designs, highlighting the interplay with operational parameters.

    Thus, this thesis identifies methods for interaction analysis and develops robust subsystem models. The integrated design tool effectively captures intra-subsystem, inter-subsystem, and cross-scalar interaction effects. The research presented contributes to the overarching project goal of developing methods and models that capture interaction effects and in turn serve as a guiding tool for designers to understand the consequences of their design choices.

    Download full text (pdf)
    vccsi_sai_licentiate
  • 2.
    Abburu, Sai Kausik
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Casanueva, Carlos
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    O'Reilly, Ciarán J.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    A Holistic Design Approach to the Mathematical Modelling of Induction Motors for Vehicle Design2023In: Procedia CIRP, 2023, Vol. 119, p. 1246-1251Conference paper (Refereed)
    Abstract [en]

    In early-stage vehicle design, there is a significant lack of knowledge about the impact of design requirements on the design of subsystems, theresulting knock-on effects between subsystems and the vehicle’s overall performance. This leads to a sub-optimal vehicle design with increaseddesign iterations. To mitigate this lack of knowledge, a cross-scalar design tool consisting of an induction motor model is presented in this paper.The tool calculates the motor’s attributes, namely its volume, mass, and the performance it can deliver to satisfy a given drive cycle’s requirements.This is achieved by breaking down the drive cycle requirements into motor parameters from which the various power losses are derived. Thesekey losses are then utilised to develop the torque/speed curve. Furthermore, it is proposed that the motor’s attributes can be used to design othersubsystems and consequently analyse their interaction effects. For example, the motor’s attributes can be used to design regenerative brakes andconsequently analyse their influence on brake wear, lifetime, and energy savings. Thus, the design tool enables the design of efficient vehicles withminimised design iterations by analysing the influence of design requirements on the subsystem’s design and the consequent interaction effectsamong the subsystems and on the vehicle’s overall performance.

    Download full text (pdf)
    math_model_motor_vehicle
  • 3.
    Abburu, Sai Kausik
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Casanueva, Carlos
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    O'Reilly, Ciarán J.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Analyzing interaction effects in a vehicle model using network theory2021In: Resource Efficient Vehicles Conference, rev2021, 2021Conference paper (Other academic)
    Abstract [en]

    The vehicle industry is moving towards developing more sustainable and efficient solutions. This movement towards sustainable and efficient solutions brings up the need to develop and integrate new subsystem technologies that are beneficial for the overall vehicle system. However, introducing new technology into an existing vehicle architecture may have knock-on effects on the dependent subsystems. Furthermore, there can be a bias towards the existing technological solutions as a large part of the architecture is developed pertaining to the established solutions. Therefore, sufficient knowledge is required to understand the level of impact the interdependencies, both direct and indirect, can have at a subsystem level and at the overall vehicle system level. To address and assess these interdependencies that arise during the conceptual design phase, a bottom-up design model is proposed. The model, utilizing network theory could represent each subsystem as nodes and their interaction effects on each other as edges. Thus, the interaction effects between different subsystems and their complex influence on the overall vehicle system are considered. This model could serve to evaluate an optimal solution in terms of functional density and economic benefits thus providing the opportunity to avoid any unintended negative indirect effects. Furthermore, it could help in identifying the technological limits in the current vehicle system and thus, identifying the areas that can be developed to further enhance the vehicle system performance. The method of implementation, its advantages, disadvantages, applications, and challenges in implementation are discussed.

  • 4.
    Abburu, Sai Kausik
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Casanueva, Carlos
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    O'Reilly, Ciarán J.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Network Theory Approach to Analysing Knock-On Effects in Rail Vehicle Design2024In: The Sixth International Conference on Railway Technology: Research, Development and Maintenance, 2024Conference paper (Other academic)
    Abstract [en]

    Rail vehicle models have become increasingly complex, posing challenges in extracting insights using traditional model representations as they require numerous iterations to achieve a satisfactory solution. This complexity leads to high computational and time costs and possibly resulting in inefficient vehicle design. To alleviate these limitations, network models are proposed as an alternative representation in this paper. These models enable the analysis of structure, behaviour, and patterns of interactions, facilitating an understanding of knock-on effects across disciplines and subsystems. The terminology, benefits, and capabilities of network theory in early-stage vehicle design are presented in this paper, along with the aspects to consider and methods for developing network models. The applicability of network theory metrics and algorithms is demonstrated using a railway traction system example. Results indicate that the proposed representations can capture complex system knock-on effects across disciplines and subsystems.

  • 5. Alkmim, M. H.
    et al.
    Cuenca, J.
    De Ryck, L.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Model-based acoustic characterisation of muffler components and extrapolation to inhomogeneous thermal conditions2018In: Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics, KU Leuven - Departement Werktuigkunde , 2018, p. 3009-3020Conference paper (Refereed)
    Abstract [en]

    A methodology for evaluating the acoustic behaviour of two-port inhomogeneous media in experimentally unavailable thermal conditions is proposed. The method consists of an inverse estimation of the geometrical and material properties of the object at room temperature followed by a forced thermal input. The properties of interest for the inverse estimation are the spatially-varying cross-section and/or bulk properties. The underlying model relies on a transfer matrix approach, allowing for a representation of spatially inhomogeneous objects as piece-wise equivalent homogeneous fluids, while ensuring continuity conditions between successive elements. A model of non-stationary thermal conduction is used as a first approximation, where an integral formulation accounts for the cumulative effect of multiple homogeneous elements. In order to evaluate the validity of the extrapolation, a validation against a fully numerical simulation is presented in two cases, namely a simple expansion chamber and a complex muffler. 

    Download full text (pdf)
    fulltext
  • 6.
    Andreolli, Raphael
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Nybacka, Mikael
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics. KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL.
    Jenelius, Erik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    O'Reilly, Ciarán J.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Falkgrim, Eric
    Scania.
    Energy Consumption Evaluation of Emerging and Current Vehicle Fleets in Urban Logistics2024In: 10th Transportation Research Arena, Dublin, Ireland, 15-18 April 2024, 2024Conference paper (Other academic)
    Abstract [en]

    Driverless multipurpose vehicles (DMVs) are an emerging vehicle concept for urban heavy-duty transport. However, little is known about their effect on urban road transport systems. Thus, the aim of this study is to analyse the total fleet energy consumption of DMVs for specific transport operations in urban logistics compared to heavy- duty battery and combustion vehicles. A novel electric vehicle routing problem was used to simulate in total 96 case-studies of operations with varying network and vehicle fleet properties. We found that the combustion vehicle fleets consumed significantly more energy for the same operation compared to the electric vehicle fleets. Although the DMV fleet and battery electric vehicle fleet showcased similar energy consumption for most case-studies, there were several operations where the DMV fleet consumed less energy and required a smaller fleet size. This study highlights the potential benefits of DMV fleets in urban logistics operations in terms of reducing total fleet energy consumption and fleet size.

  • 7.
    Andreolli, Raphael
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics. KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. Scania CV AB, Södertälje, Sweden.
    Nybacka, Mikael
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics. KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL.
    O'Reilly, Ciarán J.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Jenelius, Erik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Transport planning.
    Falkgrim, Eric
    Scania CV AB, Södertälje, Sweden.
    A review on real vehicle usage modelling of driverless multipurpose vehicles in vehicle routing problems2023In: Proceedings of the International Conference on Engineering Design, ICED 2023, Cambridge University Press (CUP) , 2023, p. 385-394Conference paper (Refereed)
    Abstract [en]

    Real vehicle usage rarely matches the predictions made during early phases of vehicle development and sales processes at commercial road vehicle manufacturers. The automotive industry needs multidisciplinary vehicle design methods to predict real-world vehicle operations by considering the vehicle level and the transport system level simultaneously, in a more holistic approach. The aim of this study was to analyse how realistic vehicle usage of driverless multipurpose vehicles can be modelled in Vehicle Routing Problems (VRPs) by conducting a systematic literature review. We found that real vehicle usage modelling of driverless multipurpose vehicles in VRPs mainly depended on the following elements: VRP variant, energy consumption model, energy consumption rate class, number of vehicle-specific design variables and transport system-level factors. Furthermore, we identified in the literature five classes of energy consumption rate edge behaviour in VRPs. These findings can support decision-making in the modelling process to select the most suitable combination of elements, and their level of detail for the overall modelling aim and purpose.

  • 8.
    Baclet, Sacha
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Bouchouireb, Hamza
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Venkataraman, Siddharth
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Gomez, Erik
    KTH.
    A machine learning- and compressed sensing-based approach for surrogate modelling in environmental acoustics: towards fast evaluation of building façade road traffic noise levels2022In: Internoise 2022: 51st International Congress and Exposition on Noise Control Engineering, The Institute of Noise Control Engineering of the USA, Inc. , 2022Conference paper (Refereed)
    Abstract [en]

    State-of-the-art urban road traffic noise propagation simulation methods such as the CNOSSOS-EU framework rely on ray tracing to estimate noise levels at specific locations on façades, so-called receiver points; this method is relatively computationally expensive and its cost increases with the number of receiver points, which limit the spatial resolution of such simulations in the context of real-time or near-real-time urban noise simulation applications. This contribution aims to investigate the applicability of multiple data-driven methods to the surrogate modelling of traffic noise propagation for fast façade noise calculation as an alternative to these traditional, ray-tracing-based methods. The proposed approach uses compressed sensing to select a small subset of optimal receiver points from which the dataset of the entire façade may be reconstructed, associated with either a kriging model or neural networks, used to predict noise levels for these sensors. The prediction performance of each of these steps is evaluated on an academic test case, with two levels of complexity based on the dimensionality of the problem.

  • 9.
    Baclet, Sacha
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH Digital Futures.
    Khoshkhah, Kaveh
    ITS Lab, Institute of Computer Science, University of Tartu, Estonia.
    Pourmoradnasseri, Mozhgan
    ITS Lab, Institute of Computer Science, University of Tartu, Estonia.
    Rumpler, Romain
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL. KTH Digital Futures.
    Hadachi, Amnir
    ITS Lab, Institute of Computer Science, University of Tartu, Estonia.
    Near-real-time dynamic noise mapping and exposure assessment using calibrated microscopic traffic simulations2023In: Transportation Research Part D: Transport and Environment, ISSN 1361-9209, E-ISSN 1879-2340, Vol. 124, article id 103922Article in journal (Refereed)
    Abstract [en]

    With prospective applications ranging from improving the understanding of the daily and seasonal dynamics of noise exposure to raising public awareness of the associated health effects, dynamic noise mapping in real time is one of the next milestones in environmental acoustics. The present contribution proposes a methodology for near-real-time dynamic noise mapping, enabling the generation of dynamic noise maps and the calculation of advanced noise exposure indicators, here arbitrarily established for the previous day, on the scale of large urban areas. This methodology consists in (i) collecting live traffic counts, measured using dedicated IoT sensors, (ii) calibrating a microscopic traffic simulation using these sparsely distributed traffic counts, (iii) modelling noise emission and propagation from the microscopic traffic simulation, and finally, (iv) post-processing the noise simulation output for the calculation of a wide range of exposure indicators. The applicability of the method is demonstrated on the city of Tartu, Estonia.

  • 10.
    Baclet, Sacha
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Venkataraman, Siddharth
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Rumpler, Romain
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    A methodology to assess the impact of driving noise from individual vehicles in an urban environment2021In: "Advances in Acoustics, Noise and Vibration - 2021" Proceedings of the 27th International Congress on Sound and Vibration, ICSV 2021 / [ed] Carletti E., Crocker M., Pawelczyk M., Tuma J., 2021Conference paper (Other academic)
    Abstract [en]

    Traffic is a major source of environmental noise pollution in urban areas. The present contribution focuses on a methodology designed to assess the impact of the noise generated by individual vehicles on a city's population using NoiseModelling, an open-source library implementing the CNOSSOS-EU model, capable of producing environmental noise maps. The initial step of the proposed method consists in processing microscopic traffic data (simulated in the present contribution), where the traffic intensity is dependent on the time of day that is targeted. The micro-traffic data is subsequently used to generate background noise maps by simulating the propagation of traffic noise. Then, the impact of the noise from the vehicle of interest is simulated, based on several parameters (route followed, type of motorization: diesel or hybrid, etc.). Finally, the data is post-processed to calculate the "exceedance" (increase in ambient noise) caused by the vehicle, taking the previously calculated background noise maps as reference. The complete methodology, its underlying assumptions, and the associated criteria proposed in order to assess the impact of noise emissions from individual vehicles is demonstrated on a realistic scenario.

    Download full text (pdf)
    fulltext
  • 11.
    Baclet, Sacha
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Venkataraman, Siddharth
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL.
    Rumpler, Romain
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL.
    Billsjö, Robin
    City of Stockholm, Transport Department, Box 8311, 104 20 Stockholm, Sweden.
    Horvath, Johannes
    City of Munich, Department of Mobility, Strategy Division, Research and Innovation Unit, 80313 Munich, Germany.
    Österlund, Per Erik
    City of Stockholm, Transport Department, Box 8311, 104 20 Stockholm, Sweden.
    From strategic noise maps to receiver-centric noise exposure sensitivity mapping2022In: Transportation Research Part D: Transport and Environment, ISSN 1361-9209, E-ISSN 1879-2340, Vol. 102, p. 103114-103114, article id 103114Article in journal (Refereed)
    Abstract [en]

    Road traffic is a major source of environmental noise pollution in urban areas. While strategic noise maps are widely used to identify the critical areas and propose mitigation plans, more specific tools are needed to evaluate the impact from traffic noise such as overall population exposure or anticipated impact from specific vehicles in varying spatiotemporal traffic conditions.

    The present contribution proposes a receiver-centric mapping approach, introducing “noise-exposure sensitivity maps”, meant to assess the potential noise exposure impact from a specific vehicle in a given network, quantifying the associated exceedance over the prevailing background noise, under varying spatiotemporal traffic conditions. The resulting maps are thus focussed on a representation of the receiver exposure as opposed to considering the noise emission and propagation alone.

    The complete methodology, its underlying assumptions, and possible applications such as route optimisation are demonstrated on realistic scenarios.

    Download full text (pdf)
    Baclet, Venkataraman, Rumpler - sensitivity mapping
  • 12.
    Baker, Dan
    et al.
    Zoox Inc.
    Sturesson, Per-Olof
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Rajgarhia, Kushal
    Zoox Inc.
    Structure-borne Road Noise Target Allocation to Tire-Wheel Subsystem in Autonomous Vehicles2023In: Aachen Acoustics Colloquium: November 27th - 29th, 2023 / [ed] Gottfried Behler, 2023Conference paper (Refereed)
    Abstract [en]

    Personal transportation as we know it is being reimagined thanks to the introduction of autonomous electric vehicles. With autonomous vehicles (AV) on the rise, especially for Transportation Network Companies (TNC), it is expected that the experience inside of the vehicle cabin will be tailored engineered for riders, not drivers. As a result, customer-facing attributes such as noise, vibration, and harshness (NVH) will need to be considered with a new perspective. Of the many challenges in developing NVH performance of an AV, road noise and component noise have, and continue, to require the most amount of development and refinement effort. It is well known that a critical component in the chain from the tire-road interface to the occupant’s ears is the tire-wheel assembly and, therefore, allocating targets for this subsystem is essential. When in motion, the tire-wheel system possesses complex structural-acoustic properties like centrifugal, gyroscopic, fluid-structure coupling, pre-load effects, and excitation that may be described by random enforced motion at the tire contact patch and road interface. Component targets are derived by experimental and virtual methods, enabling simulation-driven product development. For tire testing and development, experimental methods are often limited by the availability of complex and expensive test infrastructure. An alternative approach is explored in order to develop tire-wheel subsystem targets using experimental tests and virtual methods applying transmissibility theory with multiple degrees of freedom based on frequency response functions derived at free-free boundary conditions.

  • 13.
    Bhat, Sriharsha
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Davari, Mohammad Mehdi
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Nybacka, Mikael
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics. KTH, School of Industrial Engineering and Management (ITM), Centres, Integrated Transport Research Lab, ITRL.
    Study on energy loss due to cornering resistance in over-actuated electric vehicles using optimal control2017In: SAE International Journal of Vehicle Dynamics, Stability, and NVH - V126-10, 2017Conference paper (Refereed)
    Abstract [en]

    As vehicles become electrified and more intelligent in terms of sensing, actuation and processing; a number of interesting possibilities arise in controlling vehicle dynamics and driving behavior. Over-actuation with in- wheel motors, all wheel steering and active camber is one such possibility, which facilitate the control strategies that push boundaries in energy consumption and safety. Optimal control can be used to investigate the best combinations of control inputs to an over-actuated system. This paper shows how an optimal control problem can be formulated and solved for an over-actuated vehicle case, and highlights the translation of this optimal solution to a real-world scenario, enabling intelligent means to improve vehicle efficiency. This paper gives an insight into the Dynamic Programming (DP) as an offline optimal control method that guarantees the global optimum. Therefore the optimal control allocation to minimize an objective function and simultaneously fulfill the defined constraints can be achieved. As a case study the effect of over-actuation on the cornering resistance were investigated in two different maneuvers i.e. step steer and sine with dwell, where in both cases the vehicle assumes to be in steady state situation. In this work the cornering resistance is the main objective function and maintaining the reference trajectory is the constraint which should be fulfilled. A parameter study is conducted on the benefits of over-actuation, and depending on the type of over-actuation about 15% and 50% reduction in cornering resistance were observed during step steer and sine with dwell maneuver respectively. From a second parameter study that focused on COG position from a safety perspective, it is more beneficial for the vehicle to be designed to under-steer than over-steer. Finally, a method is described to translate the offline optimal results to vehicle implementable controllers in the form of both feed-through lookup-tables and rule-based feed-forward control.

  • 14.
    Bhat, Sriharsha
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Davari, Mohammad Mehdi
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Nybacka, Mikael
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    Study on Energy Loss due to Cornering Resistance in Over-Actuated Vehicles using Optimal Control2017In: SAE INTERNATIONAL JOURNAL OF VEHICLE DYNAMICS STABILITY AND NVH, ISSN 2380-2170, Vol. 1, no 2, p. 263-269Article in journal (Refereed)
    Abstract [en]

    As vehicles become electrified and more intelligent in terms of sensing, actuation and processing; a number of interesting possibilities arise in controlling vehicle dynamics and driving behavior. Over-actuation with in-wheel motors, all wheel steering and active camber is one such possibility, which facilitate the control strategies that push boundaries in energy consumption and safety. Optimal control can be used to investigate the best combinations of control inputs to an over-actuated system. This paper shows how an optimal control problem can be formulated and solved for an over-actuated vehicle case, and highlights the translation of this optimal solution to a real-world scenario, enabling intelligent means to improve vehicle efficiency. This paper gives an insight into Dynamic Programming (DP) as an offline optimal control method that guarantees the global optimum. Therefore the optimal control allocation to minimize an objective function and simultaneously fulfill the defined constraints can be achieved. As a case study the effects of over-actuation on the cornering resistance were investigated in two different maneuvers i.e. step steer and sine with dwell, where in both cases the vehicle assumes to be in steady state situation. In this work the cornering resistance is the main objective function and maintaining the reference trajectory is the constraint which should be fulfilled. A parameter study is conducted on the benefits of over-actuation, and depending on the type of over-actuation about 15% to 50% reduction in cornering resistance were observed during step steer and sine with dwell maneuver respectively. From a second parameter study that focused on COG position from a safety perspective, it is more beneficial for the vehicle to be designed to under-steer than over-steer. Finally, a method is described to translate the offline optimal results to vehicle implementable controllers in the form of both feed-through lookup-tables and rule-based feed-forward control.

  • 15. Blanco, B.
    et al.
    Gil-Negrete, N.
    Kari, Leif
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics, Marcus Wallenberg Laboratory MWL.
    Alonso, A.
    On the correction of rail accelerations predicted by numerical track models based on Timoshenko beam theory2021In: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, p. 1-25Article in journal (Refereed)
    Abstract [en]

    Rail accelerations can be used on the defect detection and health monitoring of railway vehicle and track components; therefore, mathematical models that predict this response are of interest for reproducing its behaviour in a wide range of situations. The numerical track models based on the Timoshenko beam theory introduce a non-physical response, which is especially noticeable in the rail accelerations. It is due to the lack of dynamic convergence of the Timoshenko finite element (FE). This paper addresses this phenomenon employing an enhanced formulation of the Timoshenko FE that includes internal degrees of freedom (iDoF). The iDoF shape functions are derived from the Timoshenko beam dynamic governing equations. Firstly, the formulation is presented, and its performance is compared with a similar Timoshenko FE formulation. Secondly, the proposal is assessed in the dynamic modelling of railway track structures. The use of iDoF efficiently corrects the non-physical response of rail accelerations by improving the FE dynamic convergence. Subsequently, a filtering criterion for accelerations is proposed, which removes the remaining non-physical response while guaranteeing the conservation of coherent frequency content. Finally, practical cases are simulated for which the proposed methodology is proved to be more efficient and reliable than the standard approach.

  • 16.
    Bouchouireb, Hamza
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Advancing the life cycle energy optimisation methodology2019Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Life Cycle Energy Optimisation (LCEO) methodology aims at finding a design solution that uses a minimum amount of cumulative energy demand over the different phases of the vehicle's life cycle, while complying with a set of functional constraints. This effectively balances trade-offs, and therewith avoids sub-optimal shifting between the energy demand for the cradle-to-production of materials, operation of the vehicle, and end-of-life phases. This work further develops the LCEO methodology and expands its scope through three main methodological contributions which, for illustrative purposes, were applied to a vehicle sub-system design case study.

    An End-Of-Life (EOL) model, based on the substitution with a correction factor method, is included to estimate the energy credits and burdens that originate from EOL vehicle processing. Multiple recycling scenarios with different levels of assumed induced recyclate material property degradation were built, and their impact on the LCEO methodology's outcomes was compared to that of scenarios based on landfilling and incineration with energy recovery. The results show that the inclusion of EOL modelling in the LCEO methodology can alter material use patterns and significantly effect the life cycle energy of the optimal designs.

    Furthermore, the previous model is expanded to enable holistic vehicle product system design with the LCEO methodology. The constrained optimisation of a vehicle sub-system, and the design of a subset of the processes which are applied to it during its life cycle, are simultaneously optimised for a minimal product system life cycle energy. In particular, a subset of the EOL processes' parameters are considered as continuous design variables with associated barrier functions that control their feasibility. The results show that the LCEO methodology can be used to find an optimal design along with its associated ideal synthetic EOL scenario. Moreover, the ability of the method to identify the underlying mechanisms enabling the optimal solution's trade-offs is further demonstrated.

    Finally, the functional scope of the methodology is expanded through the inclusion of shape-related variables and aerodynamic drag estimations. Here, vehicle curvature is taken into account in the LCEO methodology through its impact on the aerodynamic drag and therewith its related operational energy demand. In turn, aerodynamic drag is considered through the estimation of the drag coefficient of a vehicle body shape using computational fluid dynamics simulations. The aforementioned coefficient is further used to estimate the energy required by the vehicle to overcome aerodynamic drag. The results demonstrate the ability of the LCEO methodology to capitalise on the underlying functional alignment of the structural and aerodynamic requirements, as well as the need for an allocation strategy for the aerodynamic drag energy within the context of vehicle sub-system redesign.

    Overall, these methodological developments contributed to the exploration of the ability of the LCEO methodology to handle life cycle and functional trade-offs to achieve life cycle energy optimal vehicle designs.

    Download full text (pdf)
    bouchouireb2019thesis
  • 17.
    Bouchouireb, Hamza
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Jank, Merle-Hendrikje
    RWTH Aachen University, Laboratory for Machine Tools and Production Engineering (WZL), Germany.
    O'Reilly, Ciarán J.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Schöggl, Josef-Peter
    University of Graz, Institute of Systems Sciences Innovation & Sustainability Research, Austria.
    Baumgartner, Rupert J.
    University of Graz, Institute of Systems Sciences Innovation & Sustainability Research, Austria.
    Potting, José
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    The inclusion of End-Of-Life modelling in the Life Cycle Energy Optimisation methodologyManuscript (preprint) (Other academic)
    Abstract [en]

    In this work, an End-Of-Life (EOL) model is included in the Life Cycle Energy Optimisation (LCEO) methodology to account for the energy burdens and credits stemming from a vehicle’s EOL processing phase and balance them against the vehicle’s functional requirements and production and use phase energies. The substitution with a correction factor allocation method is used to model the contribution of recycling to the EOL phase’s energy. The methodology is illustrated through the optimisation of the design of a simplified vehicle sub-system. For the latter, multiple recycling scenarios with varying levels of assumed recycling induced material property degradation were built, and their impact on the vehicle sub-system’s optimal solutions was compared to that of scenarios based on landfilling and incineration with energy recovery. The results show that the inclusion of EOL modelling in the LCEO methodology can significantly alter material use patterns thereby effecting the life cycle energy of the optimal designs. Indeed, the vehicle sub-system’s optimal designs associated with the recycling scenarios are on average substantially heavier, and less life cycle energy demanding, than their landfilling or incineration with energy recovery-related counterparts.

  • 18.
    Bouchouireb, Hamza
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    O'Reilly, Ciarán J.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics.
    A preliminary investigation of robust design and uncertainty quantification within the life cycle energy optimisation methodology2021In: Resource Efficient Vehicles Conference, rev2021, 2021Conference paper (Other academic)
    Abstract [en]

    The Life Cycle Energy Optimisation (LCEO) methodology aims at finding a design solution that uses a minimum amount of cumulative energy demand over the different phases of the vehicle's life cycle, while complying with a set of functional constraints. This effectively balances trade-offs, and therewith avoids sub-optimal shifting between the energy demand for the cradle- to-production of materials, operation of the vehicle, and end-of-life phases. The present work describes the inclusion of robust design aspects and uncertainty quantification into the LCEO framework. In particular, uncertainty is introduced through the assumption that the material and energy properties of a subset of the optimisation’s candidate materials are described by statistical distributions as opposed to a priori fixed values. Subsequently, the nature of the LCEO-associated optimisation problem is changed from deterministic to stochastic. This change is handled by defining a multilevel representation hierarchy, and using the Multilevel Monte Carlo (MLMC) approach in the optimisation process to evaluate the expected compliance of a given design with the transport-related functional requirements. The extended framework is applied to the robust design optimisation of a subsystem of a vehicle model which is both mechanically and geometrically constrained. The ability of the LCEO methodology to include robust design aspects early during the vehicle design process, while simultaneously handling functional conflicts, to result in a robust life cycle energy optimal design is demonstrated. Furthermore, the performance increase obtained by the use of the MLMC approach instead of the classical Monte Carlo approach within an optimisation under uncertainty framework is illustrated.

  • 19.
    Bouchouireb, Hamza
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Väg- och spårfordon samt konceptuell fordonsdesign.
    O'Reilly, Ciarán J.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Väg- och spårfordon samt konceptuell fordonsdesign.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics.
    Exploring the aero-structural-battery energy storage coupling within the early-stage development of life cycle energy optimal electric vehiclesManuscript (preprint) (Other academic)
    Abstract [en]

    The Life Cycle Energy Optimisation (LCEO) methodology is used to explore the coupling existing between an electric vehicle's aerodynamic shape, structural material composition and design, and the properties of its onboard battery's chemistry in order to enable the development of more sustainable vehicle configurations. To this end, a mixed integer nonlinear programming formulation of the LCEO methodology was developed to include the effects of battery energy storage systems on the Life Cycle Energy (LCE) optimal vehicle designs. In particular, the vehicle's battery size and number of such batteries needed over its life cycle were introduced as variables subject to a range and a battery cycle life constraint. The former is derived from the battery-capacity-to-structural-mass ratio of recent production vehicles, while the latter ensures that the batteries' cycle lives are sufficient for the entirety of the vehicle's use phase. Additionally, three lithium-based battery chemistries with varying properties were included: lithium nickel manganese cobalt oxide (NMC), lithium iron phosphate (LFP) and lithium cobalt oxide (LCO); along with a closed-loop end-of-life recycling scenario for the battery materials. The results of the coupled aero-structural-battery energy storage LCE-driven design optimisations demonstrate that battery chemistry and recycling potential have a significant impact on the system's design in terms of overall LCE footprint, battery size and number, as well as aerodynamic shape. More specifically, a change in battery composition was found to lead to up to 12.5% variation in drag coefficient, while battery recycling can on average reduce a vehicle's associated LCE by 32%. Furthermore, battery material recycling was found to decrease the role played by the specific energy and cycle lives of the batteries, and increase that played by their embodied energy. Consequently, the LFP battery chemistry was found to be the best performer from an LCE perspective in the presence of battery material recycling; while the NMC chemistry was found to perform marginally better in the absence of the latter.

  • 20.
    Bouchouireb, Hamza
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    O'Reilly, Ciarán J.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Schöggl, Josef-Peter
    University of Graz, Institute of Systems Sciences Innovation & Sustainability Research, Austria.
    Baumgartner, Rupert J.
    University of Graz, Institute of Systems Sciences Innovation & Sustainability Research, Austria.
    Potting, José
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Architecture and the Built Environment (ABE).
    The inclusion of vehicle shape and aerodynamic drag estimations within the life cycle energy optimisation methodology2019In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 84, p. 902-907Article in journal (Refereed)
    Abstract [en]

    The present work describes a widening of the scope of the Life Cycle Energy Optimisation (LCEO) methodology with the addition of shape-related design variables. They describe the curvature of a vehicle which impacts its aerodynamic drag and therewith its operational energy demand. Aerodynamic drag is taken into account through the estimation of the drag coefficient of the vehicle body shape using computational fluid dynamics simulations. Subsequently, the aforementioned coefficient is used to calculate the operational energy demand associated with the vehicle. The methodology is applied to the design of the roof of a simplified 2D vehicle model which is both mechanically and geometrically constrained. The roof is modelled as a sandwich structure with its design variables consisting of the material compositions of the different layers, their thicknesses as well as the shape variables. The efficacy of the LCEO methodology is displayed through its ability to deal with the arising functional conflicts while simultaneously leveraging the design benefits of the underlying functional alignments. On average, the optimisation process resulted in 2.5 times lighter and 4.5 times less life cycle energy-intensive free shape designs. This redesign process has also underlined the necessity of defining an allocation strategy for the energy necessary to overcome drag within the context of vehicle sub-system redesign.

  • 21.
    Bouchouireb, Hamza
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    O'Reilly, Ciarán J.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Schöggl, Josef-Peter
    University of Graz, Institute of Systems Sciences Innovation & Sustainability Research, Austria.
    Baumgartner, Rupert J.
    University of Graz, Institute of Systems Sciences Innovation & Sustainability Research, Austria.
    Potting, José
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Towards holistic energy-efficient vehicle product system design: The case for a penalized continuous end-of-life model in the life cycle energy optimisation methodology2019In: Proceedings of the International Conference on Engineering Design, ISSN 2220-4334, E-ISSN 2220-4342, Vol. 1, p. 2901-2910Article in journal (Refereed)
    Abstract [en]

    The Life Cycle Energy Optimisation (LCEO) methodology aims at finding a design solution that uses a minimum amount of cumulative energy demand over the different phases of the vehicle's life cycle, while complying with a set of functional constraints. This effectively balances trade-offs, and therewith avoids sub-optimal shifting between the energy demand for the cradle-to-production of materials, operation of the vehicle, and end-of-life phases. The present work describes the extension of the LCEO methodology to perform holistic product system optimisation. The constrained design of an automotive component and the design of a subset of the processes which are applied to it during its life cycle are simultaneously optimised to achieve a minimal product system life cycle energy. A subset of the processes of the end-of-life phase of a vehicle’s roof are modelled through a continuous formulation. The roof is modelled as a sandwich structure with its design variables being the material compositions and the thicknesses of the different layers. The results show the applicability of the LCEO methodology to product system design and the use of penalisation to ensure solution feasibility.

  • 22.
    Bouchouireb, Hamza
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Väg- och spårfordon samt konceptuell fordonsdesign.
    O'Reilly, Ciarán J.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics.
    Schöggl, Josef-Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Baumgartner, Rupert J.
    Potting, José
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    Vehicle aerodynamic shape significantly impacted by vehicle material composition and material circularity potential in life cycle energy optimal vehicle designManuscript (preprint) (Other academic)
    Abstract [en]

    This paper explores how the systemic-level energy consumption of light-duty vehicles could be reduced through integrative design. To this end, the Life Cycle Energy Optimisation (LCEO) methodology is used to achieve the coupled optimal use of materials (including their circularity potential) and vehicle aerodynamic shape to reduce the overall Life Cycle Energy (LCE) footprint of light-duty vehicles, with the results being compared to the lightweight and aerodynamic alternatives. Initially, the methodology is functionally expanded to handle aerodynamic functional requirements through the definition of a novel allocation strategy for the aerodynamic energy, and a parametrised simple vehicle body model that ensures that the LCE knock-on effects of aerodynamically-motivated design decisions are fully accounted for. Subsequently, the methodology is used to perform the first, to the knowledge of the authors, aero-structural LCE-driven design optimisation of a vehicle subsystem, with the impact of the materials’ circularity potential being taken into account through various end-of-life (EOL) processing scenarios, including recycling. The results show that the environmental footprint of light-duty vehicles could significantly be reduced through integrative early-stage design. Specifically, it shows that a life cycle energy optimal vehicle's aerodynamic shape is significantly impacted by the vehicle's material composition and the latter's EOL characteristics — particularly recycling potential. Furthermore, LCE optimal vehicles have been found to be on average longer, heavier and more aerodynamic than their lightweight counterparts, as well as offering up to 20% energy savings per vehicle; while also being shorter and lighter than optimal aerodynamic configurations.

  • 23.
    Bouchouireb, Hamza
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Pignier, Nicolas
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    O'Reilly, Ciarán J.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Boij, Susann
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Dahan, Jeremy A.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. Siemens PLM, United Kingdom.
    Identification of noise sources on a realistic landing gear using numerical phased array methods applied to computational data2017In: 23rd AIAA/CEAS Aeroacoustics Conference, American Institute of Aeronautics and Astronautics, 2017Conference paper (Other academic)
    Abstract [en]

    The aerodynamic sound sources on a realistic landing gear are investigated using numerical phased array methods, based on array data extracted from compressible Detached-Eddy Simulations of the flow. Assuming monopole or monopole in a moving medium propagation, the sound sources are identified in the source region through various beamforming approaches: dual linear programming (dual-LP) deconvolution, orthogonal beamforming and CLEAN-SC. The predicted source locations are in good agreement with previous experimental results performed on the same nose landing gear configuration by industrial and academic partners within the ALLEGRA project. Additionally, the modeled sources are used to generate far-field spectra which are subsequently compared to the ones obtained with the Ffowcs Williams-Hawkings acoustic analogy. The results of the dual-LP approach show a good match between the far-field spectra up to a certain frequency threshold cor- responding to the quality of the mesh used. The results demonstrate the potential of numerical phased array methods as a legitimate modeling tool for aeroacoustic simulations in general and as a tool to gain insight into the noise generation mechanisms of landing gear components in particular. 

  • 24.
    Cameron, Christopher J.
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Nordgren, Eleonora Lind
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    On the balancing of structural and acoustic performance of a sandwich panel based on topology, property, and size optimization2014In: Journal of Sound and Vibration, ISSN 0022-460X, E-ISSN 1095-8568, Vol. 333, no 13, p. 2677-2698Article in journal (Refereed)
    Abstract [en]

    Balancing structural and acoustic performance of a multi-layered sandwich panel is a formidable undertaking. Frequently the gains achieved in terms of reduced weight, still meeting the structural design requirements, are lost by the changes necessary to regain acceptable acoustic performance. To alleviate this, a design method for a multifunctional load bearing vehicle body panel is proposed which attempts to achieve a balance between structural and acoustic performance. The approach is based on numerical modelling of the structural and acoustic behaviour in a combined topology, size, and property optimization in order to achieve a three dimensional optimal distribution of structural and acoustic foam materials within the bounding surfaces of a sandwich panel. In particular the effects of the coupling between one of the bounding surface face sheets and acoustic foam are examined for its impact on both the structural and acoustic overall performance of the panel. The results suggest a potential in introducing an air gap between the acoustic foam parts and one of the face sheets, provided that the structural design constraints are met without prejudicing the layout of the different foam types.

  • 25.
    Cameron, Christopher John
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Design of Multifunctional Body Panels for Conflicting Structural and Acoustic Requirements in Automotive Applications2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Over the past century, the automobile has become an integral part of society, with vastincreases in safety, refinement, and complexity, but most unfortunately in mass. Thetrend of increasing mass cannot be maintained in the face of increasingly stringentregulations on fuel consumption and emissions.The body of work within this thesis exists to help the vehicle industry to take a stepforward in producing vehicles for the future in a sustainable manner in terms of botheconomic and ecological costs. In particular, the fundamentally conflicting requirementsof low weight and high stiffness in a structure which should have good acousticperformance is addressed.An iterative five step design method based on the concepts of multifunctionality andmultidisciplinary engineering is proposed to address the problem, and explained witha case study.In the first step of the process, the necessary functional requirements of the systemare evaluated. Focus is placed on the overall system behavior and diverted from subproblems.For the case study presented, the functional requirements included: structuralstiffness for various loading scenarios, mass efficiency, acoustic absorption, vibrationaldamping, protecting from the elements, durability of the external surfaces,and elements of styling.In the second step of the process, the performance requirements of the system wereestablished. This involved a thorough literature survey to establish the state of theart, a rigorous testing program, and an assessment of numerical models and tools toevaluate the performance metrics.In the third step of the process, a concept to fulfil requirements is proposed. Here, amulti-layered, multi-functional panel using composite materials, and polymer foamswith varying structural and acoustic properties was proposed.In the fourth step of the process, a method of refinement of the concept is proposed.Numerical tools and parameterized models were used to optimize the three dimensionaltopology of the panel,material properties, and dimensions of the layers in a stepwisemanner to simultaneously address the structural and acoustic performance.In the fifth and final step of the process, the final result and effectiveness of the methodused to achieve it is examined. Both the tools used and the final result in itself shouldbe examined. In the case study the process is repeated several times with increasingdegrees of complexity and success in achieving the overall design objectives.In addition to the design method, the concept of a multifunctional body panel is definedand developed and a considerable body of knowledge and understanding is presented.Variations in core topology, materials used, stacking sequence of layers, effects ofperforations, and air gaps within the structure are examined and their effects on performanceare explored and discussed. The concept shows promise in reducing vehicleweight while maintaining the structural and acoustic performance necessary in the contextof sustainable vehicle development.

    Download full text (pdf)
    FULLTEXT02
  • 26.
    Cameron, Christopher John
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Lind, Eleonora
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Proposal of a Methodology for Multidisciplinary Design of Multifunctional Vehicle Structures including an Acoustic Sensitivity Study2009In: International Journal of Vehicle Structures & Systems, ISSN 0975-3060, Vol. 1, no 1-3, p. 3-15Article in journal (Refereed)
    Abstract [en]

    In this paper, a design methodology is proposed, wherein tools and knowledge from the areas of structural design, numerical optimization, and noise, vibration and harshness (NVH) engineering are combined into a single toolbox for vehicle design. The methodology attempts to address the topic of sustainable development from both economic and environmental perspectives within the vehicle industry. A brief review of the topics of NVH and numerical optimization is given for the purposes of disseminating knowledge. Finite element codes for predicting structural and acoustic response are implemented within the iterative design methodology, which is explained for generic problems. Specific focus is placed on the need for understanding functional requirements of the entire system rather than its components. The methodology is implemented in an automotive case study. The results in terms of design solution and development framework are evaluated and discussed. As part of this evaluation, and integral to the design process, an acoustic sensitivity analysis of the final solution is performed and the results are presented.

     

     

  • 27.
    Cameron, Christopher John
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Lind Nordgren, Eleonora
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Structural and vibroacoustics.
    A Design Method using Toplogy, Property, and Size Optimization to Balance Structural and Acoustic Performance of Sandwich Panels for Vehicle ApplicationsManuscript (preprint) (Other academic)
  • 28.
    Cameron, Christopher John
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Lind Nordgren, Eleonora
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Material Property Steered Structural and Acoustic Optimization of a Multifunctional Vehcile Body PanelManuscript (preprint) (Other academic)
    Abstract [en]

    Conventional vehicle passenger compartments often achieve functional requirements using a complex assembly of components. As each component is optimized for a single task, the assembly as a whole is often suboptimal in achieving the system performance requirements. In this paper, a novel iterative design approach based on using a multi-layered load bearing sandwich panel with integrated acoustic capabilitiesis developed focusing on material properties and their effecton the systems behavior. The proposed panel is meant to fulfilmultiple system functionalities simultaneously, thus simplifying the assembly and reducing mass. Open cell acoustic foams are used to achieve acoustic performance, and the effect of altering the stacking sequence as well as introducing an air gap within the acoustic treatment is studied in detail to determine effects on the acoustic and structural performance of the panel as a whole.

  • 29.
    Cameron, Christopher John
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Rahmqvist, Sven
    Saab Automobile AB, Technical Integration Engineer - Body Structure and Closures, Noise & Vibration Center, Sweden.
    Structural-acoustic Design of a Multi-functional Sandwich Panel in an Automotive Context2010In: Journal of Sandwich Structures and Materials, ISSN 1099-6362, E-ISSN 1530-7972, Vol. 12, no 6, p. 684-708Article in journal (Refereed)
    Abstract [en]

    This article deals with the design and weight optimization of a multi-functional vehicle body panel in an automotive context. An existing vehicle design has provided functional design requirements regarding static, dynamic, and acoustic behavior of the components of a car roof. A novel, multifunctional panel is proposed which integrates the component requirements present in a traditional roof system within a single module. The acoustic properties of two configurations of the novel panel are examined using numerical methods including advanced poro-elastic modeling tools compatible with Nastran, and compared with numerical results of a finite element model of the existing construction.

  • 30.
    Cameron, Christopher
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Lind, Eleonora
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Numerical acoustics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Balancing structural and acoustic performance of sandwich panels for vehicle applications with topology, property, and size optimization2010In: 7th Asian-Australasian Conference on Composite Materials 2010, ACCM 2010, ACCM-7 Organizing Committee , 2010, Vol. 2, p. 835-838Conference paper (Refereed)
    Abstract [en]

    Within this paper, a process for the design of a multifunctional sandwich body panel for vehicle applications is proposed. The method, presented with a case study, attempts to achieve a balance between structural and acoustic performance using numerical tools for topology optimization and combined size and property optimization. The goal of the work is to achieve an optimal distribution of traditional sandwich foam material and light weight acoustic foam within the core of the panel. The significance of the coupling between the panels inner face sheet and the acoustic foam is examined and proves to be a critical parameter in the design. An adaptation to existing topology optimization schemes is proposed to deal with the presence or absence of such a coupling. The results show promise in simplifying construction, reducing weight, and streamlining the assembly process.

  • 31.
    Carbonne, Louis
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Efraimsson, Gunilla
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Winkler, Niklas
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Use of Full Coupling of Aerodynamics and Vehicle Dynamics for Numerical Simulation of the Crosswind Stability of Ground Vehicles2016In: SAE International Journal of Commercial Vehicles, ISSN 1946-391X, E-ISSN 1946-3928, Vol. 9, no 2, p. 359-370Article in journal (Refereed)
    Abstract [en]

    The prediction in the design phase of the stability of ground vehicles subject to transient crosswinds become of increased concern with drag reduced shapes, lighter vehicles as well as platooning. The objective of this work is to assess the order of model complexity needed in numerical simulations to capture the behavior of a ground vehicle passing through a transient crosswind. The performance of a full-dynamic coupling between aerodynamic and vehicle dynamic simulations, including a driver model, is evaluated. In the simulations a feedback from the vehicle dynamics into the aerodynamic simulation is performed in every time step. In the work, both the vehicle dynamic response and the aerodynamic forces and moments are studied. The results are compared to a static coupling approach on a set of different vehicle geometries. Five car-type geometries and one simplified bus geometry are evaluated. The aerodynamic loads and moments are obtained using Detached Eddy Simulation (DES) where the motion of the vehicle is enabled using an overset mesh technique. This motion is calculated with a single-track model, including a driver model and handling two degrees of freedom, namely lateral translation and yaw motion.

    The results show that for vehicles undertaking large yaw moments and therefore large yaw motions, like the bus-type geometry, the full dynamic coupling is beneficial. In this case, a static coupling overestimates the aerodynamic loads and in turn the vehicle motion. On less crosswind sensitive vehicles, like the car-type geometries, the full-coupling approach does not modify the results in a significant way compared to a static coupling.

  • 32.
    Casanueva, Carlos
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Rail Vehicles.
    Alonso, Asier
    CAF I+D, Spain.
    Bernsteiner, Christof
    VIRTUAL VEHICLE Research Center, Austria.
    Czerwinka, Thomas
    Siemens AG, Austria.
    Gabriel, Daniel
    Stadler Rail Valencia, Spain.
    Gonzalez-Larrache, Xabier
    Siemens AG, Austria.
    Marte, Christof
    VIRTUAL VEHICLE Research Center, Austria.
    Muñoz, Jesús
    Stadler Rail Valencia, Spain.
    Orbegozo, Ane
    CAF I+D, Spain.
    Paar, Roland
    Siemens AG, Austria.
    Energy Prediction Benchmark for Universal CostModel Calculations2018Conference paper (Refereed)
    Abstract [en]

    Within the EU project Roll2Rail a Universal Cost Model (UCM) is being developed that accounts for different costs in the railway system affected by the design of the running gear. The objective of the methodology is not to calculate the global LCC of the entire vehicle (with all its components) but to boost the introduction of new technologies in the bogie by calculating the savings or incremental costs on the LCC that could be obtained between technological alternatives. The UCM will allow a more objective comparison of different bogie concepts, for instance in purchasing processes, and thus it includes a trustworthiness analysis that evaluates how accurate the calculations in the UCM are for a given study.

    When looking at the total life-cycle cost of a railway vehicle, energy consumption accounts for about 5% of the total expenditure. Within this UCM, a methodology has been proposed that allows the calculation of the energy consumption related to the bogie-technology of any railway vehicle. In order to ensure that all the calculation tools developed by the different partners are adequate, a benchmark simulation has been carried out. The benchmark studies a high-speed vehicle composed of two powered units and four non-powered ones, including six conventional bogies and three Jacobs bogies with both mechanical and ED brakes. In order to validate each simulation tool the share of energy consumed is then compared in different concepts, including in the fields of rolling resistance, curve resistance, unstable running resistance, gradient resistance, aerodynamic and turbulent resistance, inertia resistance and energy use of auxiliary elements. It should be stressed that the comparison and validation focuses on bogie-influenced energy consumption.

    In this paper, the overall UCM methodology is described, with special focus on the energy calculation methodology. The benchmark case is then presented and the energy calculation of all the partners is compared. A discussion on the calibration of the different partners' calculation tools is carried out, including a follow-updiscussion on the relative importance of the different energy consumption concepts in the final energy expenditure. Finally, the trustworthiness analysis is recalibrated according to these results. Closing remarks aregiven addressing the influence of these costs on the UCM.

    Download full text (pdf)
    fulltext
  • 33.
    Casanueva, Carlos
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Rail Vehicles. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Alonso, Asier
    Department of Applied Mechanics, CEIT, Donostia-San Sebastián, Spain.
    Giménez, José Germán
    TECNUN, University of Navarra, Donostia-San Sebastián, Spain.
    Influence of Bearing Flexibility in Rail Vehicle Dynamics2015In: The international Journal of railway technology, ISSN 2049-5358, E-ISSN 2053-602X, Vol. 4, no 1, p. 47-67Article in journal (Refereed)
    Abstract [en]

    Dynamic multibody models for railway vehicles usually assume that the stiffness of the bearings is much higher than that of the primary suspension, neglecting their effect whatsoever. This assumption might not be entirely valid for high speed vehicles, where the primary suspension is stiffer than other rail vehicles; or for more complex systems such as variable gauge wheelsets, where the whole mechanic system might have a higher than expected flexibility. In this paper, a model to obtain the stiffness of a typical configuration of railway bearings is developed and applied to both a high speed vehicle bearing set and a variable gauge wheelset bearing set. The results show that the reduction of lateral stiffness as a result of bearing flexibility can reach up to 35% of its theoretical value. This massive reduction has a major influence on the prediction of the dynamic behaviour of these vehicles, e.g. critical speed or curving performance.

  • 34.
    Casanueva, Carlos
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Enblom, Roger
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Stichel, Sebastian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Berg, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    On integrated wheel and track damage prediction using vehicle-track dynamic simulations2017In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 231, no 7, p. 775-785Article in journal (Refereed)
    Abstract [en]

    The renewal costs for wheels and rails are a substantial part of the costs for rolling stock operators and infrastructure managers all over the world. The causes for reprofiling or grinding are, in most cases, related to the following: (1) wheel or rail profiles with unacceptable wear, (2) appearance of rolling contact fatigue cracks in the surface, and (3) wheel flats caused by locking wheels during braking. The first two causes are related to the dynamic behavior of the vehicle-track system, and can be predicted using multibody simulations. However, there are several limitations that restrain the usefulness of these prediction techniques, such as simulation time constraints, necessary simplifications, and lack of experimental data that lead to educated assumptions. In this paper, we take the end-user perspective in order to show whether the latest developments in wheel-rail damage prediction can be integrated in a simplified framework, and subsequently used by the different stakeholders for an improved management of the different assets involved in the operation of rail vehicles.

    Download full text (pdf)
    fulltext
  • 35.
    Chebaeva, Natalia
    et al.
    Karl Franzens Univ Graz, Inst Syst Sci Innovat & Sustainabil Res, Merangasse 18-1, A-8010 Graz, Austria..
    Lettner, Miriam
    Kompetenzzentrum Holz GmbH, Competence Ctr Wood Composites & Wood Chem, Wood K Plus, Altenberger Str 69, A-4040 Linz, Austria.;Univ Appl Sci Kufstein Tyrol, Andreas Hofer Str 7, A-6330 Kufstein, Austria..
    Wenger, Julia
    Karl Franzens Univ Graz, Inst Syst Sci Innovat & Sustainabil Res, Merangasse 18-1, A-8010 Graz, Austria..
    Schöggl, Josef-Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. Karl Franzens Univ Graz, Christian Doppler Lab Sustainable Prod Management, Merangasse 18, A-8010 Graz, Austria..
    Hesser, Franziska
    Kompetenzzentrum Holz GmbH, Competence Ctr Wood Composites & Wood Chem, Wood K Plus, Altenberger Str 69, A-4040 Linz, Austria..
    Holzer, Daniel
    Karl Franzens Univ Graz, Inst Syst Sci Innovat & Sustainabil Res, Merangasse 18-1, A-8010 Graz, Austria..
    Stern, Tobias
    Karl Franzens Univ Graz, Inst Syst Sci Innovat & Sustainabil Res, Merangasse 18-1, A-8010 Graz, Austria..
    Dealing with the eco-design paradox in research and development projects: The concept of sustainability assessment levels2021In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 281, article id 125232Article in journal (Refereed)
    Abstract [en]

    Although plenty of research has been carried out to develop a multitude of sustainability assessment methods, few guidelines and criteria have been established to help practitioners and researchers find the most appropriate method for a specific case. Studies have shown the importance of integrating sustainability assessments when conducting research and development activities, but have not provided direct links to available sustainability assessment methods. To address the so-called "eco-design paradox", this paper describes a systematic classification system for the available sustainability assessment methods. To support the early integration of sustainability assessments in research and development, we inductively derived the concept of sustainability assessment levels from the well-known concept of technology readiness level. In total, 33 sustainability assessment methods were considered. We performed an expert-based correspondence analysis based on the availability of information to perform these methods and the demand for specific information at respective technology readiness level. Thereafter, a cluster analysis was performed, creating four distinct clusters which were finally interpreted as sustainability assessment levels. The provided concept supports interdisciplinary research projects in that it provides an overview of and guideline for possible sustainability assessment methods that match the respective technology readiness level. This enables researchers to integrate sustainability assessment into respective research and development projects and further modify and develop the theoretically synthetized concept based on empirical case studies.

  • 36.
    Cheemakurthy, Harsha
    et al.
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Lättkonstruktioner, marina system, flyg- och rymdteknik, rörelsemekanik.
    Barsoum, Zuheir
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Burman, Magnus
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Garme, Karl
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    A lightweight ice going hull concept for freshwater ice operationsManuscript (preprint) (Other academic)
    Abstract [en]

    A fundamental challenge in ice-prone waterborne public transportation systems is the need for ice-strengthening while being fuel efficient during ice-free periods. To achieve this, the use of lightweight hull structures is explored in the current study by starting with introducing a tri-layer structural concept for an ice going hull. The three layers correspond to abrasion loads, impact loads and pressure loads experienced during a typical ice-hull interaction. Several structural concepts suited towards these respective loading mechanisms are considered. Most favorable parametric variants are identified and assembled as contenders in the tri-layer concept. The assembly is tested against experimentally validated ice impact models in FEA as well as a realistic quasi-static pressure representation. Three different lightweight structural concepts including aluminum grillage, stiffened sandwich structure and metal-FRP stiffened sandwich structure are compared and discussed. It is found that the latter of the three concepts is suited best towards both quasi-static and impact loading. Ice going ferries built with ice strengthened lightweight hulls can reduce emissions, fuel consumption as well as increase the payload capacity. Such a ferry would be competitive with non-ice going ferries during ice free periods.

  • 37.
    Davari, Mohammad Mehdi
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    A tyre model for energy studies in vehicle dynamics simulations2015Licentiate thesis, comprehensive summary (Other academic)
  • 38.
    Davari, Mohammad Mehdi
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    A Multi-Line Brush Based Tyre Model to Study the Rolling Resistance and Energy Loss2015In: Proceedings of 4th International Tyre Colloquium: Tyre Models for Vehicle Dynamics Analysis, Guildford, UK (2015), 2015Conference paper (Refereed)
    Abstract [en]

    This study aim to develop a three dimensional multi-line brush based tyre model for investigating the rolling resistance and energy loss in tyres. The losses in the model are characterised by the external losses originated from the sliding phenomenon in the tyre contact patch, and the internal losses due to the tyre viscoelastic nature which is employed by a rubber model. The Extended Brush tyre Model (EBM) proposed in this work can be used to estimate the dissipated energy and the rolling resistance under different driving manoeuvres and wheel conditions. This paper focuses on the estimation of energy loss and in-plane rolling resistance.

  • 39.
    Davari, Mohammad Mehdi
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Extended Brush Tyre Model to Study Rolling Loss in Vehicle Dynamics Simulations2017In: International Journal of Vehicle Design, ISSN 0143-3369, E-ISSN 1741-5314, Vol. 73, no 4, p. 255-280Article in journal (Refereed)
    Abstract [en]

    This paper describes a semi-physical tyre model that enables studies of rolling loss in combination with vehicle dynamic simulations. The proposed model, named extended brush tyre model (EBM), takes the effects of driving conditions, wheel alignment, and tyre materials into account. Compared to the basic brush tyre model, EBM includes multiple numbers of lines and bristles as well as integrated rubber elements into the bristles. The force and moment characteristics of the model are shown to have a good correlation with the Magic Formula tyre model and experimental data. The numerically estimated rolling resistance coefficients under different conditions are compared to findings in the literature, FE-simulations and experiments. The model can capture some aspects that are not covered by the available literature and experimental observations such as camber effect on rolling loss. EBM can be used as a platform for future studies of rolling loss optimisation using active chassis control.

  • 40.
    Davari, Mohammad Mehdi
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Edrén, Johannes
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Investigating the potential of wheel corner modules in reducing rolling resistance of tires2014In: FISITA 2014 World Automotive Congress - Proceedings, FISITA , 2014Conference paper (Refereed)
    Abstract [en]

    The improvement in tire rolling efficiency is one of the key elements to optimize the fuel economy and thereby reduce the vehicle emissions. Earlier efforts to reduce the rolling resistance have mainly been focusing on new materials in the tire compounds. The overall research aim of this study is to present the potentials of implementing innovative chassis concepts with the focus on Wheel Corner Modules (WCM) by describing the possibilities in affecting rolling resistance and relating them to previous research findings. The core idea of the concept is to actively control and actuate all degrees of freedom in the wheel i.e. implementing steering, suspension and propulsion functions into a unique module which can be implemented in each corner of the vehicle. Using this concept the limitations of traditional wheel kinematics can be resolved extensively. This article presents the first step towards creating a vehicle simulation model that can show how the WCM functionality can influence the rolling resistance. A model of loss is chosen after analysing the behaviour of a three different rubber models and then implemented into a brush tire model. An effective way, but less complicated compared to current methods, to introduce the loss into tire model is presented. In conventional suspensions, the design is compromising between for example safety, comfort and rolling resistance, etc. at all driving conditions. However, using the WCM, the possibility of achieving a better compromise between those objectives is possible.Finally, based on WCM functionalities a plausible control architecture is proposed. 

  • 41.
    Davari, Mohammad Mehdi
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Jerrelind, Jenny
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Stensson Trigell, Annika
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Edrén, Johannes
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Investigating the Potential of Wheel Corner Modules in Reducing Rolling Resistance of Tyres2014In: Proceedings of FISITA "14 World Automotive Congress, Maastricht, Netherlands (2014), 2014Conference paper (Refereed)
    Abstract [en]

    The improvement in tire rolling efficiency is one of the key elements to optimize the fuel economy and thereby reduce the vehicle emissions. Earlier efforts to reduce the rolling resistance have mainly been focusing on new materials in the tire compounds. The overall research aim of this study is to present the potentials ofimplementing innovative chassis concepts with the focus on Wheel Corner Modules (WCM) by describing thepossibilities in affecting rolling resistance and relating them to previous research findings. The core idea of theconcept is to actively control and actuate all degrees of freedom in the wheel i.e. implementing steering,suspension and propulsion functions into a unique module which can be implemented in each corner of the vehicle. Using this concept the limitations of traditional wheel kinematics can be resolved extensively. This article presents the first step towards creating a vehicle simulation model that can show how the WCM functionality can influence the rolling resistance. A model of loss is chosen after analysing the behaviour of three different rubber models and then implemented into a brush tire model. An effective way, but less complicatedcompared to current methods, to introduce the loss into tire model is presented. In conventional suspensions, thedesign is compromising between for example safety, comfort and rolling resistance, etc. at all drivingconditions. However, using the WCM, the possibility of achieving a better compromise between those objectivesis possible. Finally, based on WCM functionalities a plausible control architecture is proposed.

  • 42.
    de Conchard, Antoine Vermeil
    et al.
    Univ Nantes, Dept Mech Mat & Civil Engn, Ecole Cent Nantes, Nantes, France..
    Mao, Huina
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Rumpler, Romain
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    A perfectly matched layer formulation adapted for fast frequency sweeps of exterior acoustics finite element models2019In: Journal of Computational Physics, ISSN 0021-9991, E-ISSN 1090-2716, Vol. 398, article id UNSP 108878Article in journal (Refereed)
    Abstract [en]

    Effective treatment of unbounded domains using artificial truncating boundaries are essential in numerical simulation, e.g. using the Finite Element Method (FEM). Among these, Perfectly Matched Layers (PML) have proved to be particularly efficient and flexible. However, an efficient handling of frequency sweeps is not trivial with such absorbing layers since the formulation inherently contains coupled space-and frequency-dependent terms. Using the FEM, this may imply generating system matrices at each step of the frequency sweep. In this paper, an approximation is proposed in order to allow for efficient frequency sweeps. The performance and robustness of the proposed approximation is presented on 2D and 3D acoustic cases. A generic, robust way to truncate the acoustic domain efficiently is also proposed, tested on a range of test cases and for different frequency regions. All rights reserved.

  • 43.
    Diaz, Anna
    et al.
    Karl Franzens Univ Graz, Inst Syst Sci Innovat & Sustainabil Res, Graz, Austria..
    Schöggl, Josef-Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics. Karl Franzens Univ Graz, Christian Doppler Lab Sustainable Prod Management, Graz, Austria..
    Reyes, Tatiana
    Univ Technol Troyes, Ctr Rech & Etud Interdisciplinaires Dev Durable, Troyes, France..
    Baumgartner, Rupert J.
    Karl Franzens Univ Graz, Inst Syst Sci Innovat & Sustainabil Res, Graz, Austria.;Karl Franzens Univ Graz, Christian Doppler Lab Sustainable Prod Management, Graz, Austria..
    Sustainable product development in a circular economy: Implications for products, actors, decision-making support and lifecycle information management2021In: Sustainable Production and Consumption, ISSN 2352-5509, Vol. 26, p. 1031-1045Article in journal (Refereed)
    Abstract [en]

    The concept of circular economy (CE) is of great interest for manufacturing companies since it provides a framework which allows them to align organisational objectives with the Sustainable Development Goals (SDGs). Corporate CE entails the adoption of several value-retention options (R-strategies) throughout companies' operations, which aim at creating, preserving and recovering the value of assets and products. The sustainable product development (SPD) process, in which around 80% of the total environmental impact of a product is determined, is employed to translate R-strategies into new product requirements. This study is aimed at investigating the implications of R-strategy adoption for decision-making in SPD. The research follows an empirical approach, combining a literature review and in-depth semi-structured interviews with product developers and sustainability experts working in companies operating in the technical material cycles of the CE. Thus, implications for product dimensions, inter- and intraorganisational actors, decision-making support types and lifecycle information flows so that SPD processes further accommodate CE principles into products are investigated. This study reveals new directions to adjust the contextual factors of SPD to further align existing processes with widely expanding CE organisational cultures.

  • 44.
    Diaz Tena, A.
    et al.
    University of Graz, Institute of Systems Sciences, Innovation and Sustainability Research, Graz, Austria.
    Schöggl, Josef-Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. University of Graz, Institute of Systems Sciences, Innovation and Sustainability Research, Graz, Austria.
    Reyes, T.
    University of Graz, Institute of Systems Sciences, Innovation and Sustainability Research, Graz, Austria.
    Baumgartner, R. J.
    University of Graz, Institute of Systems Sciences, Innovation and Sustainability Research, Graz, Austria.
    Exploring sustainable product development processes for a circular economy through morphological analysis2021In: Proceedings of the Design Society: 23rd International Conference on Engineering Design, ICED 2021,, Cambridge University Press , 2021, Vol. 1, p. 1491-1500Conference paper (Refereed)
    Abstract [en]

    Over the last years, academic literature has made significant progress on the development of key concepts, identifying circular product typologies, developing assessment methods, and exploring the synergies with manufacturing trends such as digitalisation or environmental management. Nevertheless, less attention has been paid on describing process model changes necessary for the implementation of circular product development. For this reason, this paper presents the circular Sustainable Product Development (cSPD) morphological field, aimed at providing implementation guidance to business and industry. It describes possible reconfigurations of the Sustainable Product Development (SPD) process model to further integrate circularity R-strategies, design scopes, design guidelines, inter- and intra-organisational actors and criteria for evaluation. With this framework, we intend to identify the most defining parameters in the process model and assign them a discrete number of categorical values so that different combinations explain the generation of prevalent circular product typologies in the manufacturing of durable goods.

  • 45.
    Dowling, Luke
    et al.
    Trinity College Dublin.
    Mao, Huina
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Flanagan, Lara
    Trinity College Dublin.
    Kennedy, John
    Trinity College Dublin.
    Rice, H J
    Trinity College Dublin.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. Siemens Industry Software, Leuven Belgium.
    A combined design-manufacturing-testing investigation of micro- to macro-scale tailoring of open poroelastic materials based on perturbed kelvin cell micro-geometries2018In: Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics, 1177 , 2018, p. 1163-1177Conference paper (Refereed)
    Download full text (pdf)
    fulltext
  • 46.
    Drugge, Lars
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Juhlin, Magnus
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    Aerodynamic loads on buses due to crosswind gusts: extended analysis2010In: Vehicle System Dynamics, ISSN 0042-3114, E-ISSN 1744-5159, Vol. 48, p. 287-297Article in journal (Refereed)
    Abstract [en]

    The objective of this work is to use inverse simulations on measured vehicle data in order to estimate the aerodynamic loads on a bus when exposed to crosswind situations. Tyre forces, driver input, wind velocity and vehicle response were measured on a typical coach when subjected to natural crosswind gusts. Based on these measurements and a detailed MBS vehicle model, the aerodynamic loads were estimated through inverse simulations. In order to estimate the lift force, roll and pitch moments in addition to the lateral force and yaw moment, the simulation model was extended by also incorporating the estimation of the vertical road disturbances. The proposed method enables the estimation of aerodynamic loads due to crosswind gusts without using a full scale wind tunnel adapted for crosswind excitation.

  • 47.
    Ejsmont, Jerzy
    et al.
    Gdańsk University of Technology, Faculty of Mechanical Engineering and Ship Technology, ul. Narutowicza 11/12, 80-233 Gdańsk, Poland.
    Ronowski, Grzegorz
    Gdańsk University of Technology, Faculty of Mechanical Engineering and Ship Technology, ul. Narutowicza 11/12, 80-233 Gdańsk, Poland.
    Ydrefors, Lisa
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Vehicle Dynamics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Owczarzak, Wojciech
    Gdańsk University of Technology, Faculty of Mechanical Engineering and Ship Technology, ul. Narutowicza 11/12, 80-233 Gdańsk, Poland.
    Sommer, Sławomir
    Gdańsk University of Technology, Faculty of Mechanical Engineering and Ship Technology, ul. Narutowicza 11/12, 80-233 Gdańsk, Poland.
    Świeczko-Żurek, Beata
    Gdańsk University of Technology, Faculty of Mechanical Engineering and Ship Technology, ul. Narutowicza 11/12, 80-233 Gdańsk, Poland.
    Comparision of tire rolling resistance measuring methods for different surfaces2024In: International Journal of Automotive Technology, E-ISSN 1976-3832Article in journal (Refereed)
    Abstract [en]

    The rolling resistance of car tires is one of the most important parameters characterizing tires today. This resistance has a very significant contribution to the energy consumption of wheeled vehicles. The climate crisis has forced tire and car manufacturers to place great emphasis on the environmental impact of their products. Paradoxically, the development of electric vehicles has led to an even greater importance of rolling resistance, because in electric vehicles a large part of the influence of grade resistance and inertial resistance has been eliminated due to re-generative braking, which resulted in rolling resistance and air resistance remain as the most important factors. What is more, electric and hybrid vehicles are usually heavier so the rolling resistance is increased accordingly. To optimize tires for rolling resistance, representative test methods must exist. Unfortunately, the current standards for measuring rolling resistance assume that tests are carried out in conditions that are far from real road conditions. This article compares the results of rolling resistance tests conducted in road conditions with the results of laboratory tests conducted on roadwheel facilities. The overview of results shows thatthe results of tests conducted in accordance with ISO and SAE standards on steel drums are very poorly correlated with more objective results of road tests. Significant differences occur both in the Coefficients of Rolling Resistance (CRR) and in the tire ranking. Only covering the drums with replicas of road surfaces leads to a significant improvement in the results obtained.For investigations of rolling resistance in non steady-state conditions, the flat track testing machine (TTF), equipped with asphalt cassettes, is shown to provide measurement data in agreement with the road test data.

  • 48.
    Eliasson, Sara
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics, Lättkonstruktioner, marina system, flyg- och rymdteknik, rörelsemekanik.
    A Framework for Fatigue Analysis of Carbon Fiber Reinforced Polymer Structures2023Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Our society depends on functional road communication, and Heavy Duty Vehicles (HDVs) offer convenient and limitless possibilities of transport and services. However, HDVs account for a quarter of the European Union's CO2 road emissions. There is a substantial need to reduce the CO2 emissions of HDVs to ensure a low negative environmental impact. To reduce the CO2 emissions of HDVs, their energy usage must be reduced. One way to reduce energy usage is to improve the structural efficiency of the vehicle and use high-performance composite materials such as Carbon Fiber Reinforced Polymers (CFRP). 

    HDVs are continuously exposed to road-induced vibrations, and the fatigue loading often sets the design criteria for HDV components. Therefore, flexible simulation frameworks are needed to encourage and simplify the implementation of composite materials in engineering structural designs dimensioned for fatigue. This doctoral thesis proposes a probabilistic modeling framework for fatigue assessment of CFRP. The thesis aims to provide knowledge and insights into the fatigue modeling of composite materials and a better understanding of the proposed modeling framework.

    A combination of experimental investigations and numerical modeling is conducted. To carry out fatigue testing, a fatigue testing procedure was established. Fatigue testing of anisotropic material involves accurately selecting process parameters to obtain specimens that fail in the gauge length. The fatigue damage progression of CFRP laminates was monitored throughout the fatigue tests by analyzing the stiffness change, finding that the initial stiffness loss can be related to the damage development of the specimens. 

    Composite materials are multi-scale, where constituents and damage are of a much lower order length scale than the laminate and structure. Therefore, the numerical modeling uses a two-scale modeling approach to capture the variability of a composite laminate. First, the micro-scale modeling uses Representative Volume Elements (RVE) to determine the effective macro-mechanical properties of a composite lamina. The RVE models are generated based on experimental data capturing micro-geometrical variations that could affect the composite laminate behavior. Second, macro-scale models, capturing the complexity and variability of composite materials, are used in a probabilistic modeling approach for fatigue assessment. A Weibull distribution in a weakest link formulation is used to consider the combined effect of material variability of a CFRP laminate. 

    The work proposes a probabilistic fatigue modeling framework for implementation in an industrial design process. The methodology is highly valuable in the progress of fatigue modeling of composites. It aims to encourage and simplify the implementation of composites in engineering structural designs and components dimensioned for fatigue. The insights and outcomes of this doctoral thesis play a crucial role in the advancement of future resource-efficient vehicles and an optimal selection of materials to design for the right material in the right place.

    Download full text (pdf)
    Summary
  • 49.
    Eliasson, Sara
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics. Scania CV AB, SE-15187 Södertälje, Sweden.
    Hagnell, Mathilda Karlsson
    RISE Res Inst Sweden, Mat & Prod Polymers Fibers & Composites, SE-16440 Stockholm, Sweden..
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Barsoum, Zuheir
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics. KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design.
    A Statistical Porosity Characterization Approach of Carbon-Fiber-Reinforced Polymer Material Using Optical Microscopy and Neural Network2022In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 15, no 19, article id 6540Article in journal (Refereed)
    Abstract [en]

    The intensified pursuit for lightweight solutions in the commercial vehicle industry increases the demand for method development of more advanced lightweight materials such as Carbon-Fiber-Reinforced Composites (CFRP). The behavior of these anisotropic materials is challenging to understand and manufacturing defects could dramatically change the mechanical properties. Voids are one of the most common manufacturing defects; they can affect mechanical properties and work as initiation sites for damage. It is essential to know the micromechanical composition of the material to understand the material behavior. Void characterization is commonly conducted using optical microscopy, which is a reliable technique. In the current study, an approach based on optical microscopy, statistically characterizing a CFRP laminate with regard to porosity, is proposed. A neural network is implemented to efficiently segment micrographs and label the constituents: void, matrix, and fiber. A neural network minimizes the manual labor automating the process and shows great potential to be implemented in repetitive tasks in a design process to save time. The constituent fractions are determined and they show that constituent characterization can be performed with high accuracy for a very low number of training images. The extracted data are statistically analyzed. If significant differences are found, they can reveal and explain differences in the material behavior. The global and local void fraction show significant differences for the material used in this study and are good candidates to explain differences in material behavior.

  • 50.
    Eliasson, Sara
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Hultgren, Gustav
    KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Barsoum, Zuheir
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Wennhage, Per
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Vehicle Engineering and Solid Mechanics.
    Probabilistic fatigue strength assessment of carbon fiber laminate: exploring effects of manufacturing defects through a two-scale modeling approachManuscript (preprint) (Other academic)
1234567 1 - 50 of 352
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf