Methodology Linking Formulation, Microstructure and Mechanical Properties of Friction Materials

An original methodology is described to characterize mechanical properties of braking sintered material from the microstructure.

Firstly, a compressive test on cube extracted from the friction pad is performed. This compressive test is instrumented with a camera leading to use the digital image correlation method giving local information. Indeed, it is possible to identify the elastic and residual strains mechanisms and to make connection with the microstructure. All these information are introduced in a finite element analysis to identify the mechanical properties of the components using an optimization algorithm. As regards of the 2D measurements, it is relevant to confirm the tendency with a 3D information. Secondly, an ex-situ compression test in a micro tomography is performed. This test is coupled to digital image correlation and a 3D simulation is performed exhibiting elastic-plastic behavior and confirming results found in the 2D study.

The methodology proposed allows determining nonlinear behavior of friction material but also identifying which components and microstructural mechanisms are involved.