A comprehensive approach for the simulation of heat and heat-induced phenomena in friction materials

• For a heterogeneous brake pad material, a 3-d temperature model is developed.
• Focus is a mesoscopic length scale with discrete cubic elements of 50 µm edge length.
• Thermal interactions between pad and disk are calculated for typical braking events.
• Physical and chemical processes inside the heterogeneous material are predicted.
• The model allows conclusions on a friction material's macroscopic performance.

The development of composite friction materials, such as organically bound brake pads, is to a great extent done on the basis of experience. Material developers have very few software tools available, which support the development process with simulations and help to reduce the number of prototypes and tests.The focus of this work is on the temperature field in organic friction materials, which is associated with many friction induced effects. To understand and predict these phenomena, a discrete model is introduced, which fully considers the material's heterogeneity down to a mesoscopic scale. Heat input and heat conduction, as well as heat transfer between pad and disk, are calculated based on a finite difference method. In order to produce stable and repeatable simulation results, a special approach for the geometrical arrangement of the different material ingredients inside the considered domain is suggested.In the context of case studies, the temperature field in a sample material is calculated for a typical stop brake application. In addition, different model extensions are discussed, which allow a spatially resolved calculation of thermally induced effects. Therewith, a comprehensive concept is presented that allows to virtually compare material variants in an early development phase. It can be easily extended with respect to further simulation tasks.

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