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  • 1.
    Abbasi, S.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Particle emissions from rail vehicles: A review2012In: Civil-Comp Proceedings, ISSN 1759-3433, Vol. 98Article in journal (Refereed)
    Abstract [en]

    Emission of airborne particles is a side effect from rail transport. This paper reviews recent research on particle emissions from rail vehicles. Both exhaust and non-exhaust particle emissions are characterized by size, morphology, composition, and size distribution. Current legislation, knowledge of adverse health effects, and available and proposed solutions for emission reductions are also treated. There has been much focus on exhaust emissions, but only a few limited studies have investigated non-exhaust particle emissions, which contain a significant amount of metallic materials. A new method for measuring the airborne wear particle emission rate (AWPER) is proposed as a first step to guide new legislations and to focus further research on non-exhaust airborne emission, i.e., research on the generation mechanisms for particle emissions and their adverse health effects. 

  • 2.
    Andersson, Kjell
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Hagnestål, Anders
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM).
    A flexible chain proposal for winch based point absorbers2018In: Proceedings of the ASME 2018 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference IDETC/CIE 2018: August 26-29, 2018, Quebec City, Quebec, Canada, 2018Conference paper (Refereed)
    Abstract [en]

    Ocean wave power is a promising renewable energy source for future energy production. It has however been difficult to find a cost-effective solution to convert the wave energy into electricity. The harsh marine environment and the fact that wave power is delivered with high forces at low speeds makes design of durable mechanical structures and efficient energy conversion challenging. The dimensioning forces strongly depend on the wave power concept, the Wave Energy Converter (WEC) implementation and the actual Power TakeOff (PTO) system. A WEC using a winch as a Power Take-Off system, i.e. a Winch Based Point Absorber (WBPA), could potentially accomplish a low Levelized Cost Of Energy (LCOE) if akey component - a low-cost, durable and efficient winch that can deal with high loads - can be developed. A key problem for achieving a durable winch is to find a force transmitting solution that can deal with these high loads and handle up to 80 million cycles. In this article we propose a design solution for a force transmitting chain in a WBPA system where elastomeric bearings are used as a means to achieve the relative motion between the links in the chain. With this solution no sliding is present and the angular motion is achieved as a deformation in the elastomeric bearing when the chain is winded on a drum. The link was designed primarily to minimize the number of joints in the chain: Thereby the maximum allowed relative angle between the links when rolled up over the drum should be as large as possible within practical limits. The angle is to be handled by the elastomeric bearing. A detailed strength analysis of the link has been performed as well as topology optimization to increase the strength to weight ratio. A test rig for a first proof of concept testing has been developed and the first preliminary test results indicate that this concept with using elastomeric bearings can be a potential solution for a durable chain and should be analyzed further for fatigue conditions and under water operations. 

  • 3.
    Andersson, Kjell
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Hagnestål, Anders
    KTH, School of Electrical Engineering and Computer Science (EECS), Electric Power and Energy Systems.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Design of a flexible chain for winch based point absorbers2018In: Proceedings of NordDesign: Design in the Era of Digitalization, NordDesign 2018, 2018Conference paper (Refereed)
  • 4.
    Bergseth, Ellen
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements. KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Henriksson, Mats
    Scania CV.
    Broukhiyan, Parsa
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Sugutur, Lohith
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Nordin, Erland
    Scania CV.
    EFFECTS OF THRUST WASHER BEARING SURFACE CHARACTERISTICS ON PLANETARY GEAR TRAIN WEAR2017Conference paper (Refereed)
  • 5.
    Bergseth, Ellen
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Henriksson, Mats
    Scania CV .
    Dizdar, Senad
    Höganäs AB.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Effects of thrust washer bearing surface characteristics on planetary gear train wear2019In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 432-433, article id 202933Article in journal (Refereed)
    Abstract [en]

    Thrust washers in spur planetary gears are placed between the planet wheel and planet carrier and act as spacers and wear pads. Metal to metal sliding contact between the planet wheel – washer – carrier causes frictional power losses that, combined with starved lubrication, may cause high contact temperatures and thermo-mechanical effects that potentially trigger thermo-elastic instabilities and excessive local wear. The planetary gear system would benefit from a low-friction interface between the washer and the planet wheel. Five washers with different surface treatments were tested in a full-scale gear rig. These tests were also replicated as closely as possible in a pin-on-disc tribometer. The following types of finishing material treatments were studied: a chemical nickel coating plus polymer on a nitro-carburised surface, a combination of nitro-carburization and solid lubricant layers, electroless deposited chemical nickel coating plus polymer, nitro-carburizing, and manganese phosphating. The frictional results indicate that tribometer tests can be used to compare and classify new washer materials. Lab scale tests show that a new experimental self-lubricating tribomaterial that was applied with laser cladding has a promising potential to increase planetary gear train robustness and service life, especially if the surface is fine grinded.

  • 6.
    Hagnestål, Anders
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Andersson, Kjell
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Durable winch-based point absorbers2017In: Proceedings of the 12th European Wave and Tidal Energy Conference 27th Aug - 1st Sept 2017, Cork, Ireland, European Wave and Tidal Energy Conference , 2017Conference paper (Refereed)
    Abstract [en]

    Wave power could give a significant contribution to a

    future sustainable energy system if the Levelized Cost Of Energy

    can be reduced to a competitive level. Winch-based point

    absorbers could potentially accomplish this if a key component –

    a low-cost, durable and efficient winch that can deal with high

    loads – can be developed. In this article the possibilities of winchbased

    point absorbers and the challenges that need to be

    overcome are described. Further, the possibilities to design such

    winches are explored and several different design approaches are

    evaluated and compared. At present, we believe that such a

    winch solution can be found although more research is needed to

    develop a full concept, and the most promising solutions so far

    involve inverted tooth chains, flat UHMwPE fiber (Dyneema)

    bands and flat carbon fibre structures.

  • 7.
    Häggström, Daniel
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM).
    Björklund, Stefan
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements. KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Evaluation of synchronizer loading parameters and their ability to predict failure2018In: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 232, no 9, p. 1093-1104Article in journal (Refereed)
    Abstract [en]

    Molybdenum coated gearbox synchronizers are tested in a mu-comp test rig under varying loading conditions until failure. Four different parameters used to describe the thermomechanical load are evaluated just before failure to compare their ability to predict failure. The parameters evaluated are the synchronized kinetic energy, the synchronization power, and the focal as well as the average surface temperature increase. The focal surface temperature increase as well as the average surface temperature increase is found to predict failure with relatively good accuracy. It is shown that there exists a threshold which divides the synchronizer into either a very long or a very short service life. Additionally, a method to determine the average surface temperature in the gearbox management system is proposed.

  • 8.
    Häggström, Daniel
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM).
    Björklund, Stefan
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Optimization of synchronizer cone angle with regards tomanufacturing tolerances of cone roundness and cone angleManuscript (preprint) (Other academic)
    Abstract [en]

    The effects from manufacturing tolerances on the maximum focal temperature has been investigated by transient thermomechanical simulations. Both relative cone angle and cone out-of-roundness for molybdenum and carbon fiber reinforced polymer (CFRP) synchronizers were evaluated. It was shown that cone out-of-roundness significantly increase the focal contact temperature for that specific cone, but has little impact on the opposing cone. Two populations of measured synchronizers were evaluated, and it was shown that the maximum focal surface temperature can be decreased in almost all tolerance cases by introducing a relative angle between the cones.

  • 9.
    Häggström, Daniel
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM).
    Björklund, Stefan
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements. KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi. KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    The effect of manufacturing tolerances on the thermomechanical load of gearbox synchronizers2018Conference paper (Refereed)
    Abstract [en]

    Transmission performance is crucial for heavy trucks and connected vehicles in general and for platooning of trucks in particular. Gearbox synchronizers are highly loaded conical friction brakes used during gear shifts. Service life and, thus, the gear shifting reliability, of the synchronizer depend on the local thermomechanical loading of the contact surface. To achieve a robust and cost-efficient system, more knowledge is needed of how manufacturing tolerances affect the local thermomechanical loading and therefore service life and reliability of a synchronizer. The effects from angle deviations between the mating cones and cone out-of-roundness on focal maximum temperature during a synchronization sequence have been studied with transient thermomechanical simulations. It is shown that thermomechanical effects will significantly magnify the nominal effects on synchronization performance caused by shape deviations given by the specified manufacturing tolerances.

  • 10.
    Häggström, Daniel
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM).
    Björklund, Stefan
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Thermomechanical performance of CFRP synchronizer friction linersManuscript (preprint) (Other academic)
    Abstract [en]

    To improve the ability of a thermomechanical simulation model for CFRP lined synchronizers to predict synchronization performance and reliability, temperature dependent material data for the specific CFRP lining is needed. The compressive modulus, coefficient of thermal expansion, specific heat and thermal conductivity are determined experimentally. The effect of each material property on the focal surface temperature is analyzed, and it is shown that the compressive modulus has the largest influence for all analyzed load cases. Physical tests show that surface hot spots begin to appear at a simulated focal surface temperature of 200 °C, while performance degradation occurs at a simulated focal surface temperature of 230 °C-250 °C.

  • 11.
    Ismoilov, Abbos
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM).
    Andersson, Kjell
    KTH, School of Industrial Engineering and Management (ITM).
    MODEL-BASED PERFORMANCE COMPARISON OF TRACKED FORWARDERSArticle in journal (Other academic)
    Abstract [en]

    The predominant forest harvesting method in northern Europe is the cut-to-length (CTL) harvesting methodthat is performed by specialized two-machines, a harvester and a forwarder, and both machines are usually sixoreight wheeled machines with pairs of wheels mounted on bogies. Under soft ground or snow conditions, bogietracks and bogie chains are used to improve mobility and tractive performance. The main engineering challengewhen developing the next generation of forwarders is to reduce whole-body vibrations and soil damage. Due tothe small global market for CTL-machines, these challenges preferably should be addressed with a singlemachine architecture.The focus of this study is to analyse and compare the interaction with very soft soil and the dynamicperformance on hard rough terrain of a medium-sized forwarder equipped with two conceptually differentforwarder track units, namely a track unit with pendulum arm suspended ground wheels and bogie suspendedground wheels, with the performance of a wheeled and bogie-type of forwarder.The simulation results show that tracked forwarders have less negative impact on the soil than wheeledforwarders due to its significantly larger footprint area. Furthermore, it is shown that tracked forwardersequipped with pendulum-arm suspended road wheels are slightly gentler for the operator in terms of whole-bodyvibrations, when operating on hard rough terrain, compared to wheeled forwarders. Furthermore, they are alsosignificantly better than the bogie-type of track unit.

  • 12.
    Lindén, Julia
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.). Scania CV AB.
    Sellgren, Ulf
    Söderberg, Anders
    Modelling uncertainty of reliability forecasts with varying operating conditionsArticle in journal (Other academic)
    Abstract [en]

    Heavy truck customers attach great importance to reliability, which make reliability assessments essential in product development projects. Since changes are easier and less expensive in early project stages, early reliability assessments are valuable. At these early stages, complete vehicle testing cannot yet be made. System reliability assessments must be made based on test data from component and subsystem tests, sometimes performed with different operating conditions than the system will be used in. Test data must be translated to the new situation, which requires information about how various factors affect reliability. Furthermore, the uncertainty in the forecast increases when the assessment is made for new operating conditions. Therefore, we also need information about how uncertainty propagates. The question is how this translation can be made, when data is sparse and expert judgement must be used, and how the increasing uncertainty can be reasonably modelled. In this paper, current methods to take into account varying operating conditions have been reviewed, and four methods have been tested in a case study. These methods are one based on fuzzy logic, a first-order second-moment reliability method (VMEA), and two variants of the proportional hazards model. The study shows that several methods are capable of handling sparse data, but only VMEA can model how uncertainty increases when operating conditions vary. It has however the drawback of being quite sensitive to uncertainty in the input data.

  • 13.
    Ramachandran, Praveen
    et al.
    KTH, School of Industrial Engineering and Management (ITM).
    Ismoilov, AbbosKTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).Sellgren, UlfKTH, School of Industrial Engineering and Management (ITM).Löfgren, BjörnSwedish Forestry Research Institute, Skogforsk.Andersson, KjellKTH, School of Industrial Engineering and Management (ITM).
    MODEL-BASED ANALYSIS OF A TRACKED FORWARDER FOR SUSTAINABLE FORESTRY2015Conference proceedings (editor) (Other academic)
    Abstract [en]

    Cut-to-length logging (CTL) is a mechanized harvesting process where trees are delimbed and cut to length directly at the stump. CTL is typically a two-man, two-machine operation with a harvester felling, delimbing, and bucking trees, and a forwarder transporting the cut logs from the felling area to a landing area accessible by trucks, or trains. The main challenges for the manufacturers of forestry machines for CTL logging are to address new customer demands and tougher ergonomic and environmental legislations by finding means that: (1) further increase the harvesting and log transportation productivity, e.g. by enabling operation on eco-soils, (2) reduce the damage to the soil, e.g. by controlling the rut depth and preserving the root layer, (3) reduce exhaust emissions, e.g. by reducing the rolling resistance and evening the contact and tractive forces between all traction units and ground, and (4) reduce the daily vibration dosage for the machine operators, e.g. with efficient chassis and cabin suspension solutions.This paper presents a model-based study of a novel tracked medium-sized forestry machine. The machine is a standard eight-wheeled forwarder of bogie type with the four bogies replaced with four passively suspended track units adapted from an off-road military vehicle. The paper briefly summarize how a tracked forwarder can be modelled and simulated using multi-body simulation software like Adams ATV and how the performance parameters can be evaluated.

  • 14.
    Sellgren, Ulf
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Williamsson, David
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Modularisation and product description: a review and a focused case2018Report (Other academic)
    Abstract [en]

    This technical report contains the results from the first step of a Ph.D. project in the field of modularisation and product description, conducted by the author at Scania CV AB in Södertälje and at KTH Royal Institute of Technology in Stockholm.Scania is one of the leading truck, bus and engine manufacturers in the world and is today a part of the Volkswagen (VW) Group AG, which is one of the world’s largest vehicle manufacturing groups. Scania has a successful history in vehicle modularisation and claims it is one of the most important reasons why they are a leading company today. Scania also has a unique way of describing the modular product in their generic product structure, in order to efficiently describe the many product variants. However, the Scania product has over the last years been developed into a mechatronic product with embedded software in focus, demanding the product description as well as the modularisation methodology to support this new dimension. Collaboration within the Volkswagen group also makes it even more important to understand and explain “The Scania Way” of modularising and describing the product.The purpose of the study presented in this technical reports was to investigate the present state at Scania, concerning product architecting, modularisation, product description and configuration. Hence, this report contains a literature review, a case study based on semi-structured interviews, as well as an architecture analysis of some main Scania components. The analysed main components were chosen to both include mechanical, electrical and software disciplines, in order to highlight some of the challenges when modularising and describing a high-performing product configured from heterogeneous technologies that are developed and managed multidisciplinary. Another purpose of the report was to answer the research questions; what is the present state at Scania, regarding product architecture and management of product data? And what are the unique properties in the modular product architecture at Scania and how are they used, developed and maintained?The result of the analysis indicates that the nomenclature needs to be further defined at Scania, preferably with a definition which is consistent in order to reduce the risk of confusion and design mistakes during future collaborations. Scania strives to maximise the number of product variants (external variety), while keeping the number of technical solutions low (internal commonality). Hence, a structured methodology which supports the development of the product architecture is clearly needed at Scania, in order to make future collaborations as efficient and successful as possible, and to control the increasing technical complexity in the future Cyber-Physical Systems. Finally, configuration rules are identified to be highly important in order to successfully realise a modular product architecture, since the architecture normally will not be fully uncoupled. A drawback with this approach is that the solution space (i.e. all valid configurations) becomes extremely hard to identify, therefore an advanced product description methodology is essential.

  • 15.
    Sun, Xuan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Andersson, Kjell
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Design optimization of haptic device - A systematic literature reviewIn: Article in journal (Refereed)
    Abstract [en]

    Performance requirements for high-performing haptic devices are usually multi-criteria. Sometimes the requirements are interacting, and several of them are conflicting. Optimization is one of the main approaches to scrutinize the design space and to search for a design that satisfies all requirements. Many researchers have used and published optimization approaches to search for an optimal haptic device design. However, predicting the performance of a high-performing haptic device usually involves computationally intensive simulations and analyses with complex and heterogeneous models. In order to study what are the common design and performance requirements of haptic devices and what optimization approaches have been used to improve optimization effectiveness and efficiency, a literature review on the present state-of-the-art in these areas has been performed. The most commonly used performance requirements presented in the literature are the number of degrees-of-freedom, dynamic inertia, kinematic isotropy, stiffness, peak and continuous force, position/force resolution, and bandwidth. Furthermore, parallel and hybrid kinematic structures are more commonly used than serial structures. Multi-objective optimization (MOO) is a commonly used approach to simultaneously optimize all performance criteria. The most common optimization targets, as presented in published literature, are to maximize workspace, kinematic isotropy, as well as the peak force/torque provided by the device, and to minimize the dynamic inertia. Commonly used indices to constrain the design space are a minimum workspace, avoidance of singularities and motion limits of active and passive joints. The number of design variables varies from 2 to 9, and the most commonly used design variables are a set of mechanical parameters, such as the lengths and diameters of the mechanical components. To increase the efficiency of complex and multi-criteria optimization tasks, the Pareto-front approach combined with multidisciplinary design optimization (MDO) and metamodel techniques are recommended.

  • 16.
    Sun, Xuan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Andersson, Kjell
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    The search for an efficient design optimization methodology for haptic devicesIn: Engineering with Computers, ISSN 0177-0667, E-ISSN 1435-5663Article in journal (Refereed)
    Abstract [en]

    Design optimization of haptic devices must manage multiple objectives,complex models, and time-consuming simulations. This paper proposes amethodology to eciently and eectively optimize the design of a high-performing6-degree-of-freedom (DOF) haptic device. The proposed methodology adapts ametamodel selection method called Predictive Estimation of Model Fidelity (PEMF)method, and integrates it with metamodel-based design optimization (MBDO)process in a multi-tool framework. A 6-DOF TAU haptic device, with two designobjectives, the global isotropy index (GII) and the dexterous workspace volumeindex (VI), is used to exemplify and verify the methodology. Two additional studiesare made to nd the most suitable sample size for metamodel training, and tostudy the eects of metamodel combinations on the solution accuracy. The generalityof the ndings is veried with MBDO of a completely dierent 6-DOF hapticdevice based on a Stewart Platform. The proposed metamodel-based methodologyreduces the computational time about 27 times as compared to using the fullmodel. For the specied design optimization problem, 300 sample points are ableto provide accurate enough metamodels and system solutions. The combination ofthe best-t metamodel for each design objective, Kriging (KR) for GII and RadialBasis Functions (RBF) for VI, can provide suciently accurate solutions whichlikely are applicable for all types of 6-DOF haptic devices.

  • 17.
    Sun, Xuan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Andersson, Kjell
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Efficient and situated design of haptic devicesIn: Article in journal (Refereed)
    Abstract [en]

    It is a challenging task to develop and optimize a high-performing haptic device for, e.g., medical training,because of the multi-objective performance requirements, and the complex relations between the design variablesand the performance objectives. Consequently, the solution space is scrutinized with efficient optimization techniques,and the cause-effect relations are preferably represented in a way that enables further reasoning in amulti-discipline setting, e.g., as Pareto-front curves and surfaces. Furthermore, if we have found a Pareto-optimalsolution, how can we benefit from the knowledge and optimization results obtained in that process if we are facinga trailing challenge (a new design situation) to re-design the initial solution to another application and/or otherrequirements, i.e. how can we address this new situation by efficiently re-using as much as possible of the initialsolutions? In this paper, we first present multi-objective optimizations of a 6-degree-of-freedom TAU haptic device.To investigate how we efficiently can address new design situations, by making use of the initial solutions, we havedefined, solved and analyzed six re-design cases. For the different cases, it is shown what can be reused and inwhat way that can be done. The six studied cases are then analyzed and a generic process for situated designoptimization, based on available knowledge and Pareto-optimal solutions, is proposed.

  • 18.
    Törngren, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Embedded Control Systems.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Complexity challenges in development of cyber-physical systems2018In: Principles of modeling: Essays dedicated to Edward A. Lee on the occasion of his 60th birthday / [ed] Marten Lohstroh, Patricia Derler, Marjan Sirjani, Switzerland: Springer, 2018, p. 478-503Chapter in book (Refereed)
    Abstract [en]

    In embarking towards Cyber-Physical Systems (CPS) withunprecedented capabilities it becomes essential to improve our understanding ofCPS complexity and how we can deal with it. We investigate facets of CPScomplexity and the limitations of Collaborating Information Processing Systems(CIPS) in dealing with those facets. By CIPS we refer to teams of humans andcomputer-aided engineering systems that are used to develop CPS. Furthermore,we specifically analyze characteristic differences among software and physicalparts within CPS. The analysis indicates that it will no longer be possible to relyonly on architectures and skilled people, or process and model/tool centeredapproaches. The tight integration of heterogeneous physical, cyber, CPS components,aspects and systems, results in a situation with interfaces and interrelationseverywhere, each requiring explicit consideration. The role of modelbasedand computer aided engineering will become even more essential, anddesign methodologies will need to deeply consider interwoven systems andsoftware aspects, including the hidden costs of software.

  • 19. Williamsson, D.
    et al.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Product architecture transition in a modular cyber-physical truck2019In: Journal of Computing and Information Science in Engineering, ISSN 1530-9827, E-ISSN 1944-7078, Vol. 19, no 3, article id 031002Article in journal (Refereed)
    Abstract [en]

    A modular product architecture is a strategic means to deliver external variety and internal commonality. In this paper, we propose a new clustering-based method for product modularization that integrates product complexity and company business strategies. The proposed method is logically verified by a studied industrial case, where the architecture of a heavy truck driveline is analyzed in terms of how it has evolved over a couple of decades, due to changed business strategies and the evolution of new technology. The presented case indicates that the new methodology is capable of identifying and proposing reasonable module candidates that address product complexity as well as company-specific strategies. Furthermore, the case study clearly shows that the business strategic reasons for a specific architecture can be found by analyzing how sensitive the clusters are to changes in the module drivers (MD). © 2019 by ASME.

  • 20.
    Williamsson, David
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.). Scania CV AB.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    A Hunt For the Hidden Reasons Behind a Product Architecture2018In: DS 96: The 20th International DSM Conference, The Design Society , 2018, p. 93-103Conference paper (Refereed)
    Abstract [en]

    A modular product architecture is a strategic means to deliver external variety and internal commonality. In this paper, a heavy duty modular gearbox architecture is represented and analyzed. In focus is re-engineering of hidden technical complexity and business strategy concerns behind an existing product architecture. The architecture of the investigated gearbox is represented and analyzed with a Product Architecture DSM and the Integrated Modularization Method (IMM). Furthermore, a Cluster Match Matrix (CMM) is proposed as a means to compare multiple clustering results. The case study indicates that the IMM methodology and CMM can be used for analyzing and finding the explicit and/or implicit reason for a targeted existing product architecture.

  • 21.
    Williamsson, David
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Product Architecture Transition in a Modular Cyber-Physical Truck2018In: ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, ASME Press, 2018, Vol. Volume 1A, article id DETC2018-85364Conference paper (Refereed)
    Abstract [en]

    A modular product architecture is a strategic means to deliver external variety and internal commonality. In this paper, we propose a new clustering based method for product modularization that integrates product complexity and company business strategies. The proposed method is logically verified by a studied industrial case, where the architecture of a heavy truck driveline is analyzed in terms of how it has evolved over a couple of decades, due to changed business strategies and the evolution of new technology. The presented case indicates that the new methodology is capable of identifying and proposing reasonable module candidates that address product complexity as well as company-specific strategies. Furthermore, the case study clearly shows that the business strategic reasons for a specific architecture can be found by analyzing how sensitive the clusters are to changes in the module drivers.

  • 22.
    Williamsson, David
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Product architecture transition in an evolving multi-brand organisation2018In: Proceedings of International Design Conference, DESIGN, Glasgow, 2018, p. 929-940Conference paper (Refereed)
    Abstract [en]

    A modular architecture is a strategic means to deliver external variety and internal commonality. A methodology for product modularization that integrates complexity and strategies is proposed and logically verified with an industrial case from the heavy truck business area. The case study indicates that the new methodology is capable of identifying and proposing reasonable module candidates that address product complexity as well as company specific strategies.

  • 23.
    Williamsson, David
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    The hunt for proper relation weights in product architecture clustering2018In: Proceedings of NordDesign 2018, Linköping, Sweden, 14th - 17th August 2018, The Design Society, 2018Conference paper (Refereed)
    Abstract [en]

    A common view is that a module should be a functional building block, with well-defined and standardized interfaces between the modules, and that it should be chosen for company specific reasons. A modular product architecture is a strategic means to deliver external variety and internal commonality. Today, multiple modularisation methodologies exist to support the highly complex task to identify module candidates in the product architecting phase. One methodology is Modular Function Deployment with the Modular Indication Matrix (MIM) representation of company-specific module drivers. Other methodologies, such as Design Structure Matrix (DSM) clustering, may be used to identify modules from a technical complexity point of view. In this paper, the performance of the newly proposed Integrated Modularization Methodology (IMM), which is based on clustering of a strategically adapted DSM, is conceptually verified. The core of the IMM is to transfer company specific module drivers from the MIM into the component-DSM, before clustering this hybrid representation. A re-architecting industrial case, where a truck manufacturer with a unique business strategy had to redesign parts of its modular gearbox architecture to also become a First-Tier OEM-supplier to another large truck manufacturer, is used as test bench. Reverse engineering of the investigated gearbox architecture indicates that the current modules are most likely not only based on technical complexity concerns. They are rather derived from different types of business strategic aspects, e.g. outsourcing. The study also indicates that the IMM is capable of identifying clusters without strategic conflicts, and with the most similar result to the analysed architecture, which is assumed to be based on expert judgements.

1 - 23 of 23
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