Shim durability is an important aspect of shim performance. During the brake operation, no mechanical failure of the shim is allowed. Typically, when releasing a shim into production, durability tests must be performed to ensure no failure occurs around the locator holes, and the shim does not walk over the locators. Since the durability test requires an actual pad and shim, the mechanical retention mechanism for the shim (locators) need to be designed, and backplates must be produced. If a failure is detected during these durability tests, either the shim needs to be changed or the retention locators have to be redesigned, which could negatively impact NVH performance and project timing/costs.
In this paper, a finite element model is developed to simulate a stop in a shim durability test. The model can be used to predict stress levels at the shim’s locator holes and the failure mode of a shim during a durability test stop. Using this model, the retention mechanism on the back plate can be properly designed to avoid shim failure before the test occurs. The model is validated through correlation of the model prediction to actual durability test results. Design guidelines are also presented to improve shim durability.