HEAVY-DUTY VEHICLE BRAKE DRUM SERVICE STRESS AND SERVICE LIFE EXPECTATION

As a result of complex mechanical and thermal load that a brake drum is exposed to during use, early failures occur due to cracks. The occurrence has not been duly clarified in practice yet and it is treated in literature as a consequence of thermal cracks. Such a definition should be rechecked, since cases are known in which the brake drum has lasted throughout the expected service life in spite of thermal cracks being present. Two stages should be distinguished in the whole process separately. In the first stage, initial thermal cracks occur; in the second stage, propagation of the initial cracks takes place as a consequence of mechanical service load and residual stresses. The analysis presented in this paper is a contribution to a clarification of the problem, since it enables an estimation of the brake drum service life.