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  • 1. Alemani, Mattia
    et al.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Perricone, Guido
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Wahlström, Jens
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Ciotti, Alessandro
    A study on the load level influence on particulate matter emissions from the sliding contact between a low steel friction material and cast iron2015Conference paper (Refereed)
  • 2. Alemani, Mattia
    et al.
    Perricone, Guido
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Wahlström, Jens
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Ciotti, Alessandro
    A proposed dyno bench test cycle to study particle emissions from disc brakes2014Conference paper (Refereed)
  • 3.
    Alemani, Mattia
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.). Brembo S.p.A, Stezzano, Italy.
    Wahlström, Jens
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Matějka, Vlastimil
    Metinöz, Ibrahim
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Perricone, Guido
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.). Brembo S.p.A, Stezzano, Italy.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Scaling effects of measuring disc brake airborne particulate matter emissions – A comparison of a pin-on-disc tribometer and an inertia dynamometer bench under dragging conditions2018In: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305XArticle in journal (Refereed)
    Abstract [en]

    An important contributor to non-exhaust emissions in urban areas is airborne particulate matter originating from brake systems. A well-established way to test such systems in industry is to use inertia dynamometer benches; although they are quite expensive to run. Pin-on-disc tribometers, on the other hand, are relatively cheap to run, but simplify the real system. The literature indicates promising correlations between these two test stands with regard to measured airborne number distribution. Recent studies also show a strong dependency between the airborne number concentration and the disc temperature. However, a direct comparison that also takes into account temperature effects is missing. The aim of this paper is, therefore, to investigate how the transition temperature is affected by the different test scales, under dragging conditions, and the effects on total concentration and size distribution. New and used low-steel pins/pads were tested against cast iron discs/rotors on both the aforementioned test stands, appositely designed for particulate emission studies. A constant normal load and constant rotational velocity were imposed in both test stands. Results show that a transition temperature can always be identified. However, it is influenced by the test scale and the frictional pair status. Nevertheless, emissions are assessed similarly when an equivalent frictional pair status is analysed (e.g. run-in). Further investigations for fully run-in samples on the pin-on-disc should be performed in order to finally assess the possibility of using the tribometers for the initial assessment of different friction materials.

  • 4.
    Andersson, Sören
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Björklund, Stefan
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Frictions models for sliding dry, boundary and mixed lubricated contacts2007In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 40, p. 580-587Article in journal (Refereed)
    Abstract [en]

    Friction, lubrication, and wear have a strong influence on the performance and behavior of mechanical systems. This paper deals with different friction models for sliding contacts running under different conditions. The models presented are suited to different situations, depending on the type of contact, running conditions, and the behavior of interest. The models will be discussed from simulation and tribological points of view. The different types of friction models considered are:

    center dot friction models for transient sliding under dry, boundary and mixed lubrication conditions,

    center dot friction models for micro-displacements of engineering surfaces subjected to transient sliding,

    center dot friction models often used in the simulation and control of technical systems,

    center dot combined friction models that represent physical behaviors fairly well but are also suitable for use in simulating systems,

    center dot friction models that take into account the stochastic nature of interacting surface asperities

  • 5.
    Andersson, Sören
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Modelling and simulation of an oscillating journal bearing of a rocker arm in a cam mechanism2008Conference paper (Other academic)
  • 6.
    Andersson, Sören
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Björklund, Stefan
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Friction models for dry, boundary and mixed lubricated contacts2004Conference paper (Other academic)
  • 7.
    Andersson, Sören
    et al.
    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 Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    A random wear model for the interaction between a rough and a smooth surface2008In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 264, no 9-10, p. 763-769Article in journal (Refereed)
    Abstract [en]

    Contact surfaces in many applications change form due to plastic and elastic deformation and to wear. This study focused on the plastic deformation and wear of the asperities on a rough surface rubbing against an opposite smooth, hard and wear-resistant surface. A stochastic model for the prediction of plastic deformations and wear of a rough surface is proposed. The surface roughness and the interaction between the surfaces are also represented by stochastic models. A single asperity is studied as it comes into contact and interacts with the opposite surface. Since the wear process is simulated as an initial-value problem, the proposed general wear model is formulated as a first order differential equation system representing events during the rubbing process at all of the asperities considered on a surface.

  • 8.
    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.
    Söderberg, Anders
    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.
    Zhu, Yi
    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.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Study of surface roughness and surface orientation on friction in rolling/sliding contacts: barrel-on-disc versus twin-disc2017Conference paper (Refereed)
    Abstract [en]

    Gears are one of the most important means of mechanical power transmission. Even though the efficiency is high for a gear pair today, further decrease in friction can contribute to lower the fuel consumption. A barrel-on-disc machine (same setup as ball-on-disc) to simulate a rolling/sliding gear contact was used to study the impact of manufacturing method, grinding and superfinishing, on friction. To evaluate the extent to which friction and wear can be diminished by reducing surface roughness and changing surface orientation. Measurement results showed that the change of lubricant had an impact on friction in the mixed to boundary lubrication regimes similar to that of the change of main surface orientation. The results were compared with those from a parallel study involving a twin-disc machine, also used to simulate rolling/sliding contacts (see Figure). Measurements and simulations showed that the barrel-on-disc and twin-disc setups reflected the same friction trends. However, the friction coefficient using the barrel-on-disc setup was almost twice as large as that found using the twin-disc machine. The wear mechanisms also differed: micropits occurred on discs used in the twin-disc set-up whereas normal or no wear was found on the barrel-on-disc specimens. The difference in contact geometry is believed to be the main reason for the higher friction level in the barrel-on-disc machine. A computer contact analysis was used to clarify the differences using perfectly smooth and computer-generated textured surfaces.

  • 9.
    Edin Grimheden, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Mechatronics.
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Building program communities on many levels: group-, department-, school-, university-, national and international mechanical engineering program communities2018In: Proceedings of the Conference KTH Scholarship of Teaching and Learning, 2018Conference paper (Refereed)
  • 10.
    Edin Grimheden, Martin
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Mechatronics.
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Teaching Gender Equality, Diversity and Equal Treatment in a Mechanical Engineering Program2019In: Proceedings of the Conference KTH Scholarship of Teaching and Learning, 2019Conference paper (Refereed)
  • 11. Jansson, Anders
    et al.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sundh, Jon
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Wahlström, Jens
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Ultrafine Particle Formation from Wear2010In: The International Journal of Ventilation, ISSN 1473-3315, E-ISSN 2044-4044, Vol. 9, no 1, p. 83-88Article in journal (Refereed)
    Abstract [en]

    Much attention is given to the consequences of airborne particles on human health and well-being. Wear is one source of airborne particles and contributions in the urban environments from wheel-to-rail contacts and disc brakes cannot be neglected. Traditionally, mechanical wear has been associated with the generation of particles of diameters of some microns. However, the research described has found ultrafine particle generation from wear processes. Particle generation from wear was measured under controlled laboratory conditions. The wear was created through sliding contact in a tribometer (type "pin-on-disc") with different materials and with different sliding velocities and pressures, to represent rail traffic and automobile disc braking. Particle concentrations and size distributions in the air were determined for particle diameters from 10 nm up to more than 10 mu m. For most materials and conditions three particle size modes were found: one at 50-100 nm, one at a few hundred nm and one at a few mu m particle diameter.

  • 12.
    Lindén, Julia
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.). Scania CV AB.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    DSM-based Reliability Analysis of Modular Architectures2015In: Modeling and managing complex systems: Proceedings of the 17th International DSM Conference Fort Worth (Texas, USA), 4-6 November 2015 / [ed] Tyson R. Browning, Steven D. Eppinger, Danilo Marcello Schmidt, Udo Lindemann, München: Carl Hanser Verlag GmbH, 2015, p. 111-122Conference paper (Refereed)
    Abstract [en]

    The main function of a heavy truck is to transport goods. Furthermore,the truck is directly operated by a driver, who has several additional functionalrequirements, of both ergonomic and communicative characters. Transport is a trustbusiness and today’s just-in-time delivery systems rely on getting the goods on time.Product reliability, which is the ability of a system to perform according to itsfunctional targets, is consequently a crucially important property for a heavy truck.This paper proposes a structure for a system reliability model that integrates differentand complementary representations, such as Function-Means trees and DesignStructure Matrix. The novelty of the presented approach is that it treats andintegrates the technical and the human subsystems through the human-technicalsystem interfaces in an extended DSM. The proposed reliability systems approachis verified with a component analysis case study of a truck cab and driver system.

  • 13.
    Lindén, Julia
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.). Scania CV AB, Sweden.
    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.).
    Model-based reliability analysis2016In: Artificial intelligence for engineering design, analysis and manufacturing, ISSN 0890-0604, E-ISSN 1469-1760, Vol. 30, no 3, p. 277-288Article in journal (Refereed)
    Abstract [en]

    The main function of a heavy truck is to transport goods, with ton-kilometers/year as an example of a major quantitative performance measure. Furthermore, the truck is directly operated by a driver, who has several additional functional requirements, of both ergonomic and communicative characters. Failure of these functions may be a subjective experience, differing between drivers, but the failures are still important. Today's just-in-time delivery systems rely on getting the goods on time, and this requires high availability. Availability is reduced not only by technical failures but also by subjectively experienced failures, because these also require repairs, or downtime. Product reliability is a systems property that cannot be attributed to a single component. It is in many cases related to interaction between components, or to interaction between humans and the technical system, in the case of subjectively experienced failures. Reliability assessments of systems with interactive functions require a system model that includes the interfaces between the technical system and human features that are carriers of interactive functions. This paper proposes a model of system architecture, for the purpose of reliability assessments, that integrates different and complementary representations, such as function-means diagrams and a design structure matrix. The novelty of the presented approach is that it treats and integrates the technical and the human subsystems through the human-technical system interfaces. The proposed systems reliability approach is described and verified with a component analysis case study of an extended truck cab and driver system.

  • 14.
    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.

  • 15.
    Lindén, Julia
    et al.
    KTH. Scania CV AB, Sweden.
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM).
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM).
    Reliability Assessment with Varying Operating Conditions2016In: Procedia CIRP, Elsevier, 2016, p. 796-801Conference paper (Refereed)
    Abstract [en]

    Product reliability is a systems property that cannot be attributed to a single component. It is in many cases related to interactions between components, or to interactions between humans and the technical system. Product functionality includes both technical functions, like structural integrity and interactive functions, like ergonomics. Reliability assessments in the early stages of the development process are valuable, since design changes cost significantly less if made early. System reliability tests can only be made towards the end of the development process, but early estimates can be based on test data from component tests and function tests. Operating conditions often vary between component tests and system tests. Therefore, reliability assessments where data from one situation is used to predict reliability in a different situation must take this variation into account. We investigate how this can be done for both technical and interactive functions. The study is made in the context of system reliability for heavy trucks, where both technical functions and interactive functions affect product reliability. Two cases have been assembled from test data, one concerning a component on a truck cab, the other an interactive function of a truck. Two reliability estimation methods have been evaluated to investigate if the methods can be used for interactive functions as well as for technical functions. We conclude that a method for reliability estimation of interactive functions must be able to model increased uncertainty due to intrapersonal variation.

  • 16.
    Lyu, Yezhe
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Wahlström, Jens
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Matějka, Vlastimil
    Brembo.
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Ranking of conventional and novel disc brake materials with respect to airborne particle emissions2017In: Eurobrake 2017, 2017Conference paper (Refereed)
  • 17.
    Olofsson, Ulf
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Wahlström, Jens
    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 Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Jansson, Anders
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Airborne Wear Particles from Disc Brakes: A Comparison of Measurements from Cars, Test Stands and Material Tests2008Conference paper (Other academic)
  • 18. Perricone, Guido
    et al.
    Matejka, Vlastimil
    Alemani, Mattia
    Valota, Giorgio
    Bonfanti, Andrea
    Ciotti, Alessandro
    Olofsson, Ulf
    Söderberg, Anders
    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.). KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Wahlström, Jens
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.). KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements. KTH, School of Industrial Engineering and Management (ITM), Applied Mechanical Engineering (KTH Södertälje). KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Nosko, Oleksii
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Straffelini, Giovanni
    Gialanella, Stefano
    Ibrahim, Metinoz
    A concept for reducing PM10 emissions for car brakes by 50%2018In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 396, p. 135-145Article in journal (Refereed)
    Abstract [en]

    With regard to airborne particles with an aerodynamic diameter of less than 10 mu m (PM10), in countries in the European Union, the mass of brake emissions equals approximately 8-27% of the total traffic-related emissions. Using a research methodology combining tests at different scale levels with contact mechanics simulations and PM10 chemical characterization, the REBRAKE EU-financed project had the following aims: i) to demonstrate the possibility of reducing the PM10 fraction of the airborne particulate from brake wear by 50 wt%; ii) to enhance the general understanding on the physical and chemical phenomena underlying the brake wear process. The results achieved so far indicate that it is possible to design a disc brake system for a European standard car affording at least a 32 wt% PM10 emission reduction using a standard European pad and a heat-treated rotor. A further reduction to 65 wt% PM10 emission could be achieved with NAO pad material and the same heat-treated disc.

  • 19.
    Sellgren, Ulf
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Robust Brake-Feel Design2009Conference paper (Other academic)
  • 20.
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Interface modeling - friction and wear2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The general trend toward increased use of computer models and simulations during product development calls for accurate and reliable product models. The function of many products relies on contact interfaces between interacting components. Simulating the behavior of such products requires accurate models of both components and interfaces. Depending on the purpose of the simulation, interface models of different degrees of detail are needed. In simulating very large systems with many interfaces, it might be computationally expensive to integrate detailed models of each individual interface. Condensed models, or abstractions, that describe the interface properties with the fewest degrees of freedom are therefore required. This thesis deals with the modeling and simulation of mechanical interfaces in a systems context. The five appended papers discuss the issue from both the simulation and tribological points of view. The aim is to study how friction and wear can be modeled in the behavioral simulation of technical systems and to discuss the convenience and applicability of using different types of models as building blocks of a system model in simulations. Paper A reviews existing friction models of sliding contacts under different running conditions. Paper B uses a simplified contact model, the elastic foundation model, to model friction in a boundary-lubricated rolling and sliding contact. The model is integrated into a dynamic rigid body model of a mechanical system, and the system behavior is simulated. Paper C discusses the application of the elastic foundation model to rough surface contact problems and investigates how the error in its results depends on surface roughness. Papers D and E address how the wear of the contact surfaces at the pad-to-rotor interface in a passenger car disc brake can be simulated using finite element analysis (FEA).

  • 21.
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    On interface modeling  with emphasis on friction2006Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The general trend toward increased use of computer models and simulations during product development has led to a need for accurate and reliable product models. The function of many products relies on contact interfaces between interacting components. To simulate the behavior of such products, accurate models of both components and interfaces are required. Depending on the purpose of the simulation, interface models of different degrees of complexity are needed. In simulation of very large systems with many interfaces, it might be computationally expensive to integrate detailed models of each individual interface. Condensed models, or abstractions, that describe the interface properties with a minimum of degrees of freedom are therefore required.

    This thesis deals with mechanical interfaces with an emphasis on friction. In the four appended papers friction models are discussed in terms of condensed models, as well as in terms of more detailed contact models. The aim is to study how friction can be modeled in behavioral simulation of products and to discuss the convenience and relevance of using different types of friction models as building blocks of a system model in behavioral simulations.

    Paper A presents a review of existing condensed friction models for sliding contacts under different running conditions and discusses the models from both simulation and tribological points of view.

    In papers B and C a simplified contact model, called the elastic foundation model, is used to model friction in a boundary-lubricated rolling and sliding contact. The model is integrated in a dynamic rigid body model of a mechanical system, the system behavior is simulated, and the result is compared with experimental results.

    Paper D discusses the application of the elastic foundation model to rough surface contact problems and investigates how the error in the elastic foundation results depends on surface roughness.

  • 22.
    Söderberg, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Andersson, Sören
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Simulation of wear and contact pressure distribution at the pad-to-rotor interface in a disc brake using general purpose finite element analysis software2008Conference paper (Other academic)
    Abstract [en]

    Passenger car disc brakes are safety-critical components whose performance depends strongly on contact conditions at the pad-to-rotor interface. The interface can be classified as a conformal dry sliding contact. During braking both brake pad and rotor surfaces are worn, affecting the useful life of the brake as well as its behavior. This paper discusses how wear of the pad-to-rotor interface can be predicted using general purpose finite element analysis software. A three-dimensional finite element model of the brake pad and the rotor is developed to calculate the pressure distribution in the pad-to-rotor contact. A wear simulation procedure based on a generalized form of Archard's wear law and explicit Euler integration is used to simulate the wear of the brake pad under steady-state drag conditions.

  • 23.
    Söderberg, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Andersson, Sören
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Simulation of wear and contact pressure distribution at the pad-to-rotor interface in a disc brake using general purpose finite element analysis software2009In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 267, no 12, p. 2243-2251Article in journal (Refereed)
    Abstract [en]

    Passenger car disc brakes are safety-critical components whose performance depends strongly on contact conditions at the pad-to-rotor interface. The interface can be classified as a conformal dry sliding contact. During braking both brake pad and rotor surfaces are worn, affecting the useful life of the brake as well as its behavior. This paper discusses how wear of the pad-to-rotor interface can be predicted using general purpose finite element analysis software. A three-dimensional finite element model of the brake pad and the rotor is developed to calculate the pressure distribution in the pad-to-rotor contact. A wear simulation procedure based on a generalized form of Archard's wear law and explicit Euler integration is used to simulate the wear of the brake pad under steady-state drag conditions.

  • 24.
    Söderberg, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Björklund, Stefan
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Validation of a simple contact model and its applicability on rough surfaces2006In: Proceedings of 12th Nordic Symposium on Tribology NORDTRIB 2006, 2006Conference paper (Refereed)
  • 25.
    Söderberg, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Björklund, Stefan
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Validation of a simplified numerical contact model2008In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 41, no 9-10, p. 926-933Article in journal (Refereed)
    Abstract [en]

    Surface roughness tends to have a significant effect on how loads are transmitted at the contact interface between solid bodies. Most numerical contact models for analyzing rough surface contacts are computational demanding and more computationally efficient contact models are required. Depending on the purpose of the simulation, simplified and less accurate models can be preferable to more accurate, but also more complex, models. This paper discusses a simplified contact model called the elastic foundation model and its applicability to rough surfaces. The advantage of the model is that it is fast to evaluate, but its disadvantage is that it only gives an approximate solution to the contact problem. It is studied how surface roughness influences the errors in the elastic foundation solution in terms of predicted pressure distribution, real contact area, and normal and tangential contact stiffness. The results can be used to estimate the extent of error in the elastic foundation model, depending on the degree of surface roughness. The conclusion is that the elastic foundation model is not accurate enough to give a correct prediction of the actual contact stresses and contact areas, but it might be good enough for simulations where contact stiffness are of interest.

  • 26.
    Söderberg, Anders
    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.).
    Modelling strain hardening and strain rate hardening of dual phase steels in finite element analysis of energy absorbing components2005Conference paper (Other academic)
  • 27.
    Söderberg, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Sellgren, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Andersson, Sören
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Using finite element analysis to predict the brake pressure needed for effective rotor cleaning in disc brakes2008In: SAE Technical Paper 2008-01-2565, USA: SAE , 2008, p. 1-10Conference paper (Refereed)
    Abstract [en]

    This paper presents an approach to simulating wear on both contact surfaces at the pad-to-rotor interface in discbrakes using general purpose finite element software. Itrepresents a first step toward a method of simulating the brake pressure needed to effectively clean the rotor ofunwanted oxide layers. Two simulation cases are presented. The first addresses running-in wear underconstant load and corresponds to repeated brakeapplications at the same constant brake load. Thesecond studies what will happen if a lower load is applied after the contact surfaces have been run-in at ahigher load level. This lower load is applied to wear off an oxide layer after a sequence of repeated stop braking at higher load levels.

  • 28.
    Söderberg, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Spiegelberg, Christer
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Modeling transient behavior of a mechanical system including a rolling and sliding contact2005In: Proceedings of IMECE 1005, 2005 ASME Interantional Mechanical Engineering Congress and Exposition, 2005, p. 229-238Conference paper (Refereed)
    Abstract [en]

    Thefriction and wear of rolling and sliding contacts are criticalfactors for the operation of machine elements such as bearings,gears, and cam mechanisms. In precision machines, for example, themain concern is to compensate for frictional losses, so asto improve control accuracy. In other applications it is oftendesirable to minimize friction losses to improve efficiency, though sometimeshigh friction is desired to prevent sliding and wear. Theaim of this study is to simulate the behavior ofa test equipment and show that simulations can be usedto study and optimize mechanical systems that include rolling andsliding contact. Simulations can be used to study the systemas a whole, as well as the contact conditions. Thetest equipment and the measurement procedure used are described. Inthe simulations, a contact model designed to handle transient contactconditions is integrated into a system model. The results showthat the contact strongly influences the system. The simulations showthat the use of a contact model allows the simulationof systems that contain contacts with different amounts of slip,and that such simulations can be used to study thecontact as well as the system. Surface roughness influences thecontact stiffness and is included in the simulations.

  • 29.
    Söderberg, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Spiegelberg, Christer
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Simulation models of test equipment for measuring transient friction in a rolling and sliding contact2005In: Proceedings of OST ’05 Symposium On Machine Design, 2005Conference paper (Refereed)
    Abstract [en]

    This paper investigates how a model for boundary lubricated rolling and sliding contacts can be integrated in a dynamic rigid body model of a mechanical system in order to improve the accuracy of simulations of system behavior. The system modeled is test equipment for the measurement of transient friction in rolling sliding contact between two discs. Two different models of the system were constructed: one neglecting the rolling and sliding contact and the other integrating it in the system model. In the integrated contact model, the pressure distribution was computed using an elastic foundation model. A brush model was used for the friction calculation. Simulations were performed with both models and validated by experiments. The results show that the contact needs to be included in the model in order to capture the behavior of the system. Since the contact model used can handle both microslip and gross slip, it is applicable to a wide range of contact conditions.

  • 30.
    Söderberg, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Wahlström, Jens
    KTH, School of Industrial Engineering and Management (ITM), Applied Mechanical Engineering (KTH Södertälje).
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering.
    Jansson, Anders
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    On Airborne Wear Particles Emissions ofCommercial Disc Brake Materials– A Pin on Disc Simulation2008Report (Other academic)
    Abstract [en]

    A novel test method was used to study the concentration and size distribution of airborne wear particles from disc brake materials. A pin-on-disc tribometer equipped with particle counting instruments was used as test equipment. Four different nonasbestoses-organic (NAO) linings for the U.S. market and four different low metallic linings for the EU market were tested against material from gray cast iron rotors. The result indicates that the low metallic linings are more aggressive to the rotor material then the NAO linings, resulting in higher amount of wear and concentrations of airborne wear particles. But, although there are variations in the measured particle concentrations, similar size distributions were obtained regardless of lining material.

  • 31. Valota, Giorgio
    et al.
    De Luca, Stefano
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Use of FEA to clarify pin-on-disc tribometer tests executed with disc brake material2015Conference paper (Other academic)
  • 32.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Matějka, V.
    Lyu, Yezhe
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Contact pressure and sliding velocity maps of the friction, wear and emission from a low-metallic/cast-iron disc brake contact pair2017In: Tribology in Industry, ISSN 0354-8996, Vol. 39, no 4, p. 460-470Article in journal (Refereed)
    Abstract [en]

    Particulate matter with an aerodynamic diameter less than 10 µm (PM10) from car disc brakes contribute up to 50% of the total non-exhaust emissions from road transport in the EU. These emissions come from the wear of the pad and rotor contact surfaces. Yet few studies have reported contact pressures and offered sliding speed maps of the friction, wear, and particle emission performance of disc brake materials at a material level. Such maps are crucial to understanding material behaviour at different loads and can be used as input data to numerical simulations. A low-metallic pad and grey cast-iron rotor contact pair commonly used today in passenger car disc brakes was studied using a pin-on-disc tribometer at twelve contact pressure and sliding speed combinations. Maps of the coefficient of friction, specific wear rate, particle number, and mass rate are presented and discussed.

  • 33.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Jansson, Anders
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    A pin-on-disc simulation of airborne wear particles from disc brakes2010In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 268, no 5-6, p. 763-769Article in journal (Refereed)
    Abstract [en]

    A novel test method was used to study the concentration and size distribution of airborne wearparticles from disc brake materials. A pin-on-disc tribometer equipped with particle countinginstruments was used as test equipment. Material from four different non-asbestos organic(NAO) pads and four different low metallic (LM) pads were tested against material from greycast iron rotors. The results indicate that the low metallic pads cause more wear to the rotormaterial than the NAO pads, resulting in higher concentrations of airborne wear particles.Although there are differences in the measured particle concentrations, similar size distributionswere obtained. Independent of pad material, the characteristic particle number distributions ofairborne brake wear particles have maxima around 100, 280, 350, and 550 nm.

  • 34.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    A disc brake test stand for measurement of airborne wear particles2009In: Lubrication Science, ISSN 0954-0075, Vol. 21, no 6, p. 241-252Article in journal (Refereed)
    Abstract [en]

    During braking, there is wear on both the rotor and the pads. This process generates particles that may becomeairborne. In field tests, it is difficult to distinguish these particles from others in the surrounding environment.Therefore, a laboratory test stand has been designed which allows control of the cleanliness of the surroundingair. The test stand consists of a front right brake assembly mounted in a sealed chamber. A braking load is appliedby a pneumatic system and the rotor, which has been pre-conditioned with a rust layer to simulate a car standingparked overnight in a wet environment, is driven by an electric motor. The number and size of airborne wearparticles are then measured. This experimental set-up has been verified by an initial test series performed at lowbraking loads. The results suggest that this test stand can be used to study rust layer removal from the rotor.

  • 35.
    Wahlström, Jens
    et al.
    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 Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Services Engineering (name changed to Building Service and Energy Systems 2012-03-01).
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    A disc brake test stand for measurement of airborne wear particles2008Conference paper (Refereed)
  • 36.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.).
    Jansson, Anders
    A pin-on-disc simulation of airborne wear particles from disc brakes2009Conference paper (Refereed)
  • 37.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olander, Lars
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Jansson, Anders
    Airborne wear particles from passenger car disc brakes: a comparison of measurements from field tests, a disc brake assembly test stand, and a pin-on-disc machine2010In: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 224, no J2, p. 179-188Article in journal (Refereed)
    Abstract [en]

    Most modern passenger cars have disc brakes on the front wheels.Unlike drumbrakes,disc brakes are not sealed off from the ambient air. During braking, both the rotor and the padswear, and this wear process generates particles that may become airborne. In field tests it isdifficult to distinguish these particles from others in the environment. It is thus preferable toconduct tests using laboratory test stands where the cleanness of the surrounding air can becontrolled.However, the validity of results fromthese test stands should be verifiedbycomparisonwith field tests. This article presents a comparison of the number and volume distributions ofairborne wear particles as measured online in field tests, in a disc brake assembly test stand,and in a pin-on-disc machine. In all cases, grey cast iron rotors and low metallic pads weretested. A promising correlation between the three different test methods is shown. The numberandvolume-weighted mean particle diameter for all test methods is about 0.4 and 2–3μm,respectively.

  • 38.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    A cellular automaton approach to numerically simulate the contact situation in disc brakes2011In: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 42, no 3, p. 253-262Article in journal (Refereed)
    Abstract [en]

    Since brake wear is an important contributor to the concentration of airborne particles in urban atmospheres, it is important to increase our understanding of the origin of these particles. The contact situation between the pad and disc is complicated. Metal fibres in the pad (or other hard materials) form stable contact plateaus, which carry the main part of the load. A flow of wear particles in the boundary layer between the pad and disc partially stack up against these plateaus (and increase their area), and some will escape from the contact and become airborne. The purpose of this article is to investigate the possibility to numerically simulate the contact situation in the boundary layer between the pad and disc and the amount of wear that leaves the contact using a cellular automaton approach. To do so, the contact pressure, pad temperature and wear are determined in that order. Based on these results, the creation, growth and destruction of contact plateaus are simulated using a cellular automaton model. Finally, the amount of wear that leaves the contact is determined. The simulated behaviour of the contact situation correlates qualitatively with experimental observations found in the literature.

  • 39.
    Wahlström, Jens
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Design (Div.).
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Simulation of airborne wear particles from disc brakes2009In: SAE Technical Paper 2009-01-3040, USA: SAE , 2009Conference paper (Refereed)
    Abstract [en]

    During braking, both the rotor and the pads are worn in disc brakes. This wear process generates particles which may become airborne. In passenger car field tests it is difficult to distinguish these particles from others in the surrounding environment. It may therefore be preferable to use laboratory test stands and/or simulation models to study the amount of airborne wear particles generated. This paper discusses the possibility of predicting the number distribution of airborne wear particles generated from the pad to rotor contact in disc brakes by using general purpose finite element software. A simulation methodology is proposed where the particle coefficient is established by testing at material level. This coefficient is then used in numerical wear simulation at component level. The simulated number distribution is compared to experimental measurements at component level. The result indicates that the proposed methodology may be used to predict the number and distribution of airborne particles generated from the pad to rotor contact.

  • 40.
    Wahlström, Jens
    et al.
    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 Elements.
    Ulf, Olofsson
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Machine Elements.
    A cellular automaton approach to simulate the contact situation between the pad and disc in disc brakes2010Conference paper (Refereed)
  • 41. 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.

  • 42.
    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.

  • 43.
    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.

  • 44.
    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.

  • 45.
    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.

  • 46.
    Zhu, Yi
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Olofsson, Ulf
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Söderberg, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Tribologi.
    Adhesion modeling in the wheel-rail contact under dry and lubricated conditions using measured 3D surfaces2013In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 61, p. 1-10Article in journal (Refereed)
    Abstract [en]

    Adhesion between wheels and rails plays an essential role in the safe, efficient, and reliable operation of a railway network. Particularly under lubricated conditions, which can be a natural lubricant as water and an applied lubricant as rail oil, trains can experience adhesion loss. This paper presents an adhesion model constructed using the measured 3D wheel-rail surfaces. The numerical model comprises of three parts: a normally loaded contact model; an interfacial fluid model; and a rolling-sliding contact model. Simulation examples use the numerical model to investigate how water or oil contamination might affect wheel-rail adhesion in contacts with different surface roughness levels. Simulation indicates that adhesion peaks are almost at the same creep on different surfaces. The fluid load capacity is inversely proportional to the adhesion coefficient, both of which are clearly dependent on vehicle speed. Oil reduces adhesion coefficient more than water does. The adhesion coefficient on the low roughness surfaces is higher than that on the generated smooth surfaces under oil-lubricated conditions while it is the opposite for water-lubricated contact.

1 - 46 of 46
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