| 1. |
- Amouzgar, Kaveh, 1980-, et al.
(författare)
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Multi-objective optimization of a disc brake system by using SPEA2 and RBFN
- 2013
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Ingår i: ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. - New York : ASME Press. - 9780791855898
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Many engineering design optimization problems involve multiple conflicting objectives, which today often are obtained by computational expensive finite element simulations. Evolutionary multi-objective optimization (EMO) methods based on surrogate modeling is one approach of solving this class of problems. In this paper, multi-objective optimization of a disc brake system to a heavy truck by using EMO and radial basis function networks (RBFN) is presented. Three conflicting objectives are considered. These are: 1) minimizing the maximum temperature of the disc brake, 2) maximizing the brake energy of the system and 3) minimizing the mass of the back plate of the brake pad. An iterative Latin hypercube sampling method is used to construct the design of experiments (DoE) for the design variables. Next, thermo-mechanical finite element analysis of the disc brake, including frictional heating between the pad and the disc, is performed in order to determine the values of the first two objectives for the DoE. Surrogate models for the maximum temperature and the brake energy are created using RBFN with polynomial biases. Different radial basis functions are compared using statistical errors and cross validation errors (PRESS) to evaluate the accuracy of the surrogate models and to select the most accurate radial basis function. The multi-objective optimization problem is then solved by employing EMO using the strength Pareto evolutionary algorithm (SPEA2). Finally, the Pareto fronts generated by the proposed methodology are presented and discussed.
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| 2. |
- Hansbo, Peter, et al.
(författare)
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Least-squares stabilized augmented Lagrangian multiplier method for elastic contact
- 2016
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Ingår i: Finite elements in analysis and design (Print). - : Elsevier. - 0168-874X .- 1872-6925. ; 116, s. 32-37
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we propose a stabilized augmented Lagrange multiplier method for the finite element solution of small deformation elastic contact problems. We limit ourselves to friction-free contact with a rigid obstacle, but the formulation is readily extendable to more complex situations. © 2016 Elsevier B.V.
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| 3. |
- Rashid, Asim, 1978-, et al.
(författare)
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An Efficient Sequential Approach for Simulation of Thermal Stresses in Disc Brakes
- 2012
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Ingår i: Nordtrib 2012, 15th Nordic Symposium on Tribology, 2012.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper an efficient approach to simulate thermal stresses due to frictional heating of disc brakes is presented. Inthe approach thermal and stress analysis are performed sequentially. The frictional heat analysis is based on the Eulerianmethod, which requires significantly low computational time as compared to the Lagrangian approach. Completethree-dimensional geometries of a disc and a pad are considered for the numerical simulations. The contact forcesare computed at each time step taking the thermal deformations of the disc into account. The nodal temperaturehistory is recorded at each time step and is used in sequentially coupled stress analysis, where a temperature dependentelasto-plastic material model is used to compute the stresses in a disc brake. The results show that during hard braking,high compressive stresses are generated on the disc surface in circumferential direction which cause plastic yielding. Butwhen the disc cools down, the compressive stresses transform to tensile stresses. Such thermoplastic stress history maycause cracks on disc surface after a few braking cycles. These results are in agreement with experimental observationsavailable in the literature.
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| 4. |
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| 5. |
- Rashid, Asim, 1978-
(författare)
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Overview of Disc Brakes and Related Phenomena - a literature review
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Disc brakes have evolved over time to be a reliable method of decelerating and stopping a vehicle. There have been dierent designs of disc brake systems for dierent applications. This review gives a detailed description of dierent geometries of the components and the materials used in a disc brake system. In spite of all the improvements, there are still many issues related to disc brakes that need to be understood in a greater detail and resolved. There has been a lot of research going on about these issues and at the same time dierent methods are being proposed to eliminate or reduce them. These methods include the changes in geometry of dierent components, dierent or improved materials, addition of new components and changes in cooling methods etc. There has also been an intensive research going on about the evolution of tribological interface of disc-pad system. One major purpose of the present paper is to give a comprehensive overview of all such developments.
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| 6. |
- Rashid, Asim, 1978-
(författare)
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Overview of Disc Brakes and Related Phenomena - a review
- 2014
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Ingår i: International Journal of Vehicle Noise and Vibration. - : InderScience Publishers. - 1479-1471 .- 1479-148X. ; 10:4, s. 257-301
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Forskningsöversikt (refereegranskat)abstract
- Disc brakes have evolved over time to be a reliable method of decelerating and stopping a vehicle. There have been different designs of disc brake systems for different applications. This review gives a detailed description of different geometries of the components and the materials used in a disc brake system. In spite of all the improvements, there are still many operational issues related to disc brakes that need to be understood in greater detail and resolved. There has been a lot of research going on about these issues and at the same time different methods are being proposed to eliminate or reduce them. There has also been intensive fundamental research going on about the evolution of the tribological interface of the disc-pad system. One major purpose of the present paper is to give a comprehensive overview of all such developments.
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| 7. |
- Rashid, Asim, 1978-, et al.
(författare)
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Sequential simulation of thermal stresses in disc brakes for repeated braking
- 2013
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Ingår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology. - London, United Kingdom : Sage Publications. - 1350-6501 .- 2041-305X. ; 227:8, s. 919-929
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, an efficient sequential approach for simulating thermal stresses in brake discs for repeated braking is presented. First, a frictional heat analysis is performed by using an Eulerian formulation of the disc. Then, by using the temperature history from the first step of the sequence, a plasticity analysis with temperature dependent material data is performed in order to determine the corresponding thermal stresses. Three-dimensional geometries of a disc and a pad to a heavy truck are considered in the numerical simulations. The contact forces are computed at each time step taking the thermal deformations of the disc and pad into account. In such manner, the frictional heat power distribution will also be updated in each time step, which in turn will influence the development of heat bands. The plasticity model is taken to be the von Mises yield criterion with linear kinematic hardening, where both the hardening and the yield limit are temperature dependent. The results show that during hard braking, high compressive stresses are generated on the disc surface in the circumferential direction which cause yielding. But when the disc cools down, these compressive stresses transform to tensile residual stresses. For repeated hard braking when this kind of stress history is repeated, we also show that stress cycles with high amplitudes are developed which might generate low cycle fatigue cracks after a few braking cycles.
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| 8. |
- Rashid, Asim, 1978-, et al.
(författare)
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Thermomechanical Simulation of Wear and Hot Bands in a Disc Brake by Adopting an Eulerian Approach
- 2013
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Ingår i: Eurobrake 2013. - : FISITA.
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Konferensbidrag (refereegranskat)abstract
- In this paper frictional heating of a disc brake is simulated while taking wear into account. By performing thermomechanical finite element analysis, it is studied how the wear history will influence the development of hot bands. The frictional heat analysis is based on an Eulerian formulation of the disc, which requires significantly lower computational time as compared to a standard Lagrangian approach. A real disc-pad system to a heavy truck is considered, where complete three-dimensional geometries of the ventilated disc and pad are used in the simulations. A sequential approach is adopted, where the contact forces are computed at each time step taking the wear and thermal deformations of the mating parts into account. After each brake cycle, the wear profile of the pad is updated and used in subsequent analysis. The results show that when wear is considered, different distributions of the temperature on disc are obtained for each new brake cycle. After a few braking cycles two hot bands appear on the disc surface instead of only one. These results are in agreement with experimental observations.
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