Nonlinear Brake Squeal Analysis

Brake squeal noise is a top warranty concernsmplaints for virtually all automotive companies. How to identify squeal frequencies and mode shapes is typically very challenging. The identification of potential squeal problems still rely heavily on experimental methods using inertia and chassis dynamometers or on-road tests, but these require hardware to run. Good numerical methods have advantages of evaluating up-front designs before the cutting tools ever hit any metal. But for brake squeal, there are still many challenges to overcome to correctly model a complete brake system due to the nature of the complexity of the frictional excitation. In this paper, a disc brake system model was established to simulate brake squeal using nonlinear transient analysis methods provided through LS-DYNA. The model includes rotor, pads, linings, caliper and pistons. From the example analyzed, the squeal frequency is identified using frequency domain analysis of the numerical time-domain output. Results are checked and correlated to test results. Operational deflection shapes of rotor and pads during the numerically simulated squeal event were obtained. The nodal diametrical modes of rotor at different squeal frequencies are displayed. The relative displacements of inboard and outboard pads at different squeal frequencies are discussed.