Structural analysis of a commercial vehicle disc brake caliper

Abstract

Disc brake calipers are subjected to significant mechanical loading, with design requirements being particularly stringent with respect to the stresses, the deflections, the installation envelope, the noise, vibration, and harshness, and the thermal aspects. Modern finite element (FE) techniques can successfully model caliper assemblies; however, the limitations in predicting the caliper behaviour are primarily related to accurate definition of the boundary conditions, because of complex interactions between the individual components. Traditionally, strain gauges and displacement transducers have been used for measuring the caliper strains and deflections. This approach is expensive and time consuming, requiring installation of numerous transducers and complex data processing, and has limited accuracy. The application of digital image correlation (DIC) to a commercial vehicle disc brake caliper provided valuable strain results. In comparison with strain gauges, DIC proved to be exceptionally easy to use and enables straightforward comparison of measured strains with FE predicted values. Initial work dealt with the static actuating forces, and excellent correlation between the predicted and the measured strain values was achieved throughout the operating range of clamp forces. The present authors are confident that the addition of the dynamic frictional forces will give even more interesting results, providing insight into the interaction of different components within the brake assembly.