Analysis of the thermo-mechanical deformation of brake discs

• Applicant: Professor Dr.-Ing. Balázs Magyar
• Subject Area: Engineering Design, Machine Elements, Product Development
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 567674919

Brakes are safety-relevant elements of drive technology that decelerate mass inertia or hold it at a standstill. Mechanical friction is usually used as the operating principle for both functions. Like all other drive technology components, brakes are affected by miniaturisation and cost reduction. These trends mean that the thermo-mechanical load on the brake components and the resulting deformation of the brake discs must increasingly be regarded as a limiting factor for safe operation. To date, however, there has been a lack of a holistic explanatory model and a calculation approach based on it, which describes the interlinked interactions (cause, event, consequence) during the braking process both qualitatively and quantitatively. The aim of the proposed project is therefore to understand the complex mechanisms of action in the thermo-mechanical deformation of brake discs and, based on this, to derive design guidelines for reducing and, if necessary, avoiding them in practice. As a working hypothesis, it is assumed that uneven frictional heating of the brake disc takes place during the braking process, which leads to uneven thermal expansion. These thermal expansions, in superposition with the expansions from the mechanical stress, lead to localised stresses that locally exceed the yield point. The yield point itself is dependent on temperature, strain and strain rate. The local flow process in turn leads to a change in the component geometry, which affects the contact between the brake disc and brake pad. This in turn changes the pressure, friction and temperature distribution in the contact and thus the braking behaviour of the system. In the project, this chain of effects is to be underpinned by a qualitatively and quantitatively correct model so that measures can then be taken to eliminate the damaging effect.

• DFG Programme: Research Grants