Contact Analysis for a Passenger Car Disc Brake

The mechanical behavior of a passenger car disc brake sliding caliper is analyzed in order to better understand the parameters that influence rotor/pad pressure distribution. The analysis uses proven techniques for solving free boundary contact problems. Complementarity equations for a gap between adjacent nodes are formulated in terms of the contact compliances for the inboard and outboard pad/rotor interfaces and for the piston/inboard-shoe interface. These equations also capture the influence of rigid-body motion of the various caliper components resulting from the translation and rotation needed to satisfy static equilibrium. The finite element method is employed to calculate the compliance matrices for all the contact interfaces. An iteration scheme is developed to solve the nonlinear system of complementarity equations for each of the three contact problems.

To validate the general approach, pad/rotor pressure distributions were measured for the static, no-friction case using pressure sensitive paper. The results of the measurements agree very well with computed results.