Effect of alternation of braking conditions on friction material 2019-36-0010

The need to predict the durability of the friction material is a constant pursuit of the application engineer. In fact, the difficulty in reproducing by means of laboratory tests the actual conditions of application of the friction materials makes it essential to understand the influence of the test parameters on the wear of the friction material. Currently, durability data is extracted from dynamometer tests, where the parameters of speed, pressure, and decelerations are applied and divided into blocks of temperature, which do not represent exactly the actual driving condition of the vehicle. Thus, the objective of this study is to compare the pad wear when subjected to two wear test models: The first one is based on the wear test procedures traditionally found in the light and heavy vehicle (repetitive matrix) and the second an alternating wear matrix, which results in friction material disturbs, more similar to the field condition. The total energy and pressure, temperature and velocity parameters are the same for both matrices, and the difference is given by the alternation of the number of cycles and brake application in each temperature block. Throughout the tests, after each test temperature block, the mass measurement of the pad is performed. In this paper two distinct formulations are used, one being semi-met and the other low-met. In both formulations, the alternating matrix has approximately 30% higher wear than the repetitive wear matrix. This shows that the effects of the alternating braking conditions throughout the laboratory tests present a remarkable increase in the level of wear of the friction material.