This SAE Standard specifies necessary procedures and control parameters in estimating anisotropic elastic constants of friction material based on pad assembly FRF measurements and optimization. It is intended to provide a set of elastic constants as inputs to brake NVH simulation, with the objective of ensuring pad assembly vibration correlation between simulation and measurements.
Friction material elastic constants are required inputs to brake NVH simulations, whether at component (e.g. pad assembly FRFs) or system levels (e.g. squeal simulations). Friction materials are anisotropic (approximately transversely isotropic) and inhomogeneous (including elastic constants and densities).
Measuring elastic constants locally has its own difficulties and limitations, when used for NVH simulations:
The FRF (Frequency Response Function) measurement based method has been in use in practice for brake NVH simulations, either to provide elastic constants directly or to improve averaged elastic constants calculated based on ultrasonic measurements (see referenced publications). Therefore, it seems both necessary and beneficial to document the procedures and standardize as much as possible.