| 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. |
- Asim, Zeeshan, et al.
(författare)
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Significance of Sustainable Packaging: A Case-Study from a Supply Chain Perspective
- 2022
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Ingår i: Applied System Innovation. - : MDPI AG. - 2571-5577. ; 5:6
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Tidskriftsartikel (refereegranskat)abstract
- The present case study-based research provides insights of the current packaging practices with a supply chain perspective and proposed sustainable packaging options that would cut down the environmental impact from supply chain operations at Midas Safety. The case study is based on qualitative research that used semi-structured open-ended interviews and observations to understand the current processes of the packaging and supply chain department of Midas Safety and how they are planning to adapt sustainability to their processes. Considering the current packaging practices, the study aimed to develop improved sustainable packaging practices with a supply chain aspect in order to cut down the negative environmental aspect such as standardization in packaging for all customers, elimination of wood pallets, developing local suppliers, change in packaging design, making the packaging more compact and lightweight, reducing carbon footprint and fuel consumption by encouraging trade through sea instead of air. The results concluded that internal factors such as alternate packaging material (like Mondi’s Aegispaper, Arjowiggins’ and Corrugated Bubble Wrap) along with the suggested sustainable packaging practices discussed above and external factors such as availability of local vendors are important requirements for successful sustainable packaging development.
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| 3. |
- Hansbo, Peter, et al.
(författare)
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Least-squares stabilized augmented Lagrangian multiplier method for elastic contact
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Annan publikation (övrigt vetenskapligt/konstnärligt)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.
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| 4. |
- 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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| 5. |
- Rashid, Asim, et al.
(författare)
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An Efficient Sequential Approach for Simulation of Thermal Stresses in Disc Brakes
- 2012
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper an ecient approach to simulate thermal stresses due to tem-perature variations in disc brakes is presented. In the approach thermal and stress analysis are performed sequentially. The frictional heat analysis is based on the Eulerian method, which requires signicantly low computational time as compared to the Lagrangian approach. The nodal temperature history is recorded at each time step and is used in a sequentially coupled stress analysis, where a temperature dependent elasto-plastic material model is used to compute the stresses in the 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. But when the disc cools down, the compressive stresses transform to tensile stresses. Such thermoplastic stress history may cause cracks on disc surface after a few braking cycles. These results are in agreement with experimental observations available in the literature.
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| 6. |
- 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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| 7. |
- Rashid, Asim
(författare)
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Finite Element Modeling of Contact Problems
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Contact is the principal way load is transferred to a body. The study of stresses and deformations arising due to contact interaction of solid bodies is thus of paramount importance in many engineering applications. In this work, problems involving contact interactions are investigated using finite element modeling.In the first part, a new augmented Lagrangian multiplier method is implemented for the finite element solution of contact problems. In this method, a stabilizing term is added to avoid the instability associated with overconstraining the non-penetration condition. Numerical examples are presented to show the influence of stabilization term. Furthermore, dependence of error on different parameters is investigated.In the second part, a disc brake is investigated by modeling the disc in an Eulerian framework which requires significantly lower computational time than the more common Lagrangian framework. Thermal stresses in the brake disc are simulated for a single braking operation as well as for repeated braking. The results predict the presence of residual tensile stresses in the circumferential direction which may cause initiation of radial cracks on the disc surface after a few braking cycles. It is also shown that convex bending of the pad is the major cause of the contact pressure concentration in middle of the pad which results in the appearance of a hot band on the disc surface. A multi-objective optimization study is also performed, where the mass of the back plate, the brake energy and the maximum temperature generated on the disc surface during hard braking are optimized. The results indicate that a brake pad with lowest possible stiffness will result in an optimized solution with regards to all three objectives. Finally, an overview of disc brakes and related phenomena is presented in a literature review.In the third part, a lower limb donned in a prosthetic socket is investigated. The contact problem is solved between the socket and the limb while taking friction into consideration to determine the contact pressure and resultant internal stress-strain in the soft tissues. Internal mechanical conditions and interface stresses for three different socket designs are compared. Skin, fat, fascia, muscles, large blood vessels and bones are represented separately, which is novel in this work.
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| 8. |
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| 9. |
- 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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| 10. |
- 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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