The aim of this paper was the proposal of a numerical procedure for the structural evaluation and durability validation of brake shoes, employing fatigue and finite element softwares that are able to predict the failure locations (and number of cycles to failure) with acceptable accuracy. The software Abaqus was used in the calculation of the stress and strain fields whereas the software fe-safe was employed in the evaluation of fatigue life. Accelerated tests were performed on a bench test that has been designed to match the operating conditions of the vehicles were the brake shoes are assembled.
In those cases where only local plasticity is expected (rather than generalized plasticity) the procedure can somewhat be simplified by running linear elastic finite element analysis (instead of full non-linear), which is often called pseudo-elastic analysis [1]. Then the pseudo stresses and strains are corrected at post-processing time by means of the Neuber’s rule and Ramberg-Osgood equation [2].
The fractographies of the tested components suggest brittle failure mode, which requires a method like SWT (Smith-Watson-Topper) for the mean stress correction [10]. The full brake assembly was considered in the simulations. All the contacts are non-linear and the material of the brake lining is orthotropic.
In the present context experimental life to failure is defined as the arithmetic mean of the failed samples (there were three of them). The numerical and experimental results (in terms of life) differ by no more than 52%, and the failure locations correlate really well.
The developed numerical procedure has shown to be sufficiently accurate to replace the experimental tests. Therefore it can be used in a more comprehensive study where the sensitivity to geometry, material and loads can be investigated.