The Influnence Of Angular Distribution Of A Grooved Brake Disc Material Surface On Friction-induced Viberation And Noise

Friction-induced vibration and noise can seriously affect the accuracy and reliability and reduce the service life of the mechanical equipment.Meanwhile,it has a severe impact on the physical and mental health of people,and causes contamination and damage on our environment.Among the friction-induced vibration and noise,brake vibration and noise which is generated from train and automobile braking causes many troubles and inconvenience to people's work and lives,which is a difficult problem that is urgently need to be solved both at home and abroad.It is reported that the contact interface status characteristic is a key factor which shows significant effect on friction-induced vibration and noise,and the surface topography plays a significant role on the generation of brake noise.So,studying the influence of the grooved surface on brake noise shows great value on investigating the generation of brake noise and seeking potential way to reduce brake noise.At the first,grooves with different width are processed on the disc surface which is made from the train brake disc to conduct the small sample excrement for the purpose of finding a relatively best groove width that can suppressing the generation of brake noise.Moreover,it is investigated that the influence of the angular distribution of a grooved surface on the generation of friction-induced vibration and noise with the relatively optimal width.An experimental and numerical study is performed to study the mechanism of influence of the grooved surfaces with different angular distribution on the noise reduction.Furthermore,to verify the conclusion of the small sample study results,two representative angular grooves are processed on only half and mixed distribution of the disc surfaces to further study the effect of groove angular on noise reduction.At last,two angular distribution grooves are processed on high-speed train forged steel disc surfaces to study their effect on noise reduction using a scaling bench test platform for the purpose of further validating the noise reduction mechanism with grooved disc surfaces.Meanwhile,the influence of testing time on the noise reduction for the grooved surface is investigated using the scaling test platform.The conclusions in this work are summarized as follows:1.The experimental results indicate that the disc surface with 1 mm shows a relatively best potential on brake noise reduction in the range of widths in the paper.The test results indicated that the grooved surfaces with different angular distributions based on the optimal width of 1 mm(T-45,T-60,T-90 and T-135)have significant potential in reducing noise.From good to bad the noise reduction effects of the surfaces are,in order,T-45,T-135,T-60,and T-90 surfaces.It also shows that the worse ability of noise reduction with the increasing groove angular when the angular is ranging from 45° to 90°.2.In this paper,the mechanism of noise reduction is summarized as follows:on the one hand,the grooves on the disc surface are able to entrap wear debris and avoid the accumulation of wear debris in the contact interface,which can improve wear status of the contact surface and may help suppress the generation of noise to a certain extent.On the other hand,the grooves can interrupt and redistribute the contact pressure distribution of the contact surface,this behavior can help to avoid the accumulation of energy concentrated at the contact surface and then reduce the energy levels of friction-induced noise.3.The noise level of grooved surface is significantly lower than smooth surface,and mild wear is found on the grooved surface for the disc samples with grooves on only half grooved disc surfaces.For the grooved part,the 45° groove shows a better ability on noise reduction than 90° groove.The suppression ability to friction-induced vibration and noise is decreased in order of T-h-45/90,T-h-45 and T-h-90 surfaces,the interference time of these three surfaces decreased in succession.All of these results well validate the noise reduction mechanism which is proposed in the paper.4.Bench tests show that compared with smooth surface,grooved surfaces can obviously suppress the generation of brake noise,and the suppression effect of T-45 surface is better than T-90 surface,which has good consistency with the result of sample experiment.With the increase of testing time,the noise reduction efficiency of the grooved surfaces is still maintained.Moreover,the noise reduction mechanism which is proposed in the paper is further verified by the analysis of worn states and interference time of the contact interface.