| Friction-induced noise is a kind of unstable voice, which is resulted from the vibration of the friction behaviors between the contact surfaces. Friction-induce vibration and noise not only seriously affects the reliability, precision and working life of many equipment, but also leads to serious noise pollution which is bad for the physical and psychological health of people. Friction-induce vibration and noise is caused by the friction behaviors between the contact surfaces, so the characteristics of the interface are the key influence factors to the friction-induce vibration and noise. At present, the study of the effect of the interface characteristic on the friction-induce vibration and noise is focus on the surface topography, abrasive dust and so on. In recent years, surface texture has been identified to be of a significant influence factor on friction characteristic, however, there are few reports on the effect of the surface texture on the friction-induce vibration and noise. Therefore, it is of great significance and importance to study the effect and the mechanism of the surface texture on friction-induce vibration and noise. The study will be helpful to control and reduce the friction-induce vibration and noise.In this work, groove-textured surfaces with different angles (0°,45°,90°,135°) are manufactured on the train brake pad friction material surfaces. In addition, groove-textured surface (T-30°-1) is manufactured on the train brake disc surface. An experimental study is conduct to investigate the influence of the groove-textured surfaces on the friction-induce vibration and noise by using the smooth train brake disc surface and the smooth train brake pad friction material surface as the counterface, respectively. Subsequently, a numerical study is performed to simulate the experimental process through the finite software ABAQUS. Based on the experimental and numerical results, the effect and the mechanism of groove-textured surface on the friction-induce vibration and noise are discussed. The main conclusions are as follows:1. In the experimental study, the results of the friction noise character analysis show that for the brake pad friction material, the 45° and 90° grooved surfaces can significantly recue squeal noise,135° grooved surface can reduce the squeal noise at some level. The T-30°-1 grooved brake disc surface can significantly recue squeal noise.2. The results of complex eigenvalue analysis show that the calculating main frequency is very close the experimental testing main frequency for every kind of surface. The 3-D finite elementary model is reliable and can be used to study the effect of the groove-textured surface on the friction-induced vibration and noise in the dynamic transient analysis.3. The dynamic transient analysis results agree with the experimental results well. For the brake pad friction material, the scales of vibration acceleration amplitude range from large to small for the 0°,135°,45°,90°rooved surfaces. For the brake disc, the vibration acceleration can be observed for the smooth surface. The vibration acceleration amplitude shows higher fluctuations when the brake pad friction material impacts the groove edges for the T-30°-1 grooved surface, but the fluctuations decay very soon.4. The results of the contact pressure distribution analysis show that the values of the highest contact pressure and also the area of the contact pressure distribution range from large to small for the 0°,135°,45°,90° grooved surfaces; and the uniformity of the contact pressure distribution range from bad to well for the 0°,135°,45°,90° grooved surfaces. The significant reduction of the squeal noise of the 45° and 90° grooved surfaces is resulted from the smaller values of the highest contact pressure, the larger area of the contact pressure distribution, and the more uniform contact pressure distribution. For the brake disc, the contact pressure distribution area is larger for the T-30°-1 grooved surface, and the contact pressure distribution is the more uniform, and the highest contact pressure distribution is lower compared with the smooth brake disc surface. In addition, the higher contact pressure concentrates on the edges of the grooves. It can infer that there is fierce collision between the edges of the brake pad friction material and the grooves when the brake pad friction material crosses the grooves. The continuous contact of the friction system is interrupted, and the continuous self-excited vibration of the system is disturbed, and the squeal noise is efficiently suppressed. |
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