| With the acceleration of urbanization,the running speed of urban rail trains has gradually increased,and the braking mode has transitioned from tread braking to disc braking.Lightweight and low-noise aluminum-based composite brake discs have shown broad application prospects in the field of urban rail transit.The purpose of this paper is to carry out a comparative analysis of the compatibility of two brake disc materials and three brake pad materials through the material reduction test,discuss the feasibility of local replacement of aluminum alloy brake discs,and clarify the aluminum-based composite brake.The friction characteristics of the friction pair of the disc and the synthetic brake pad reveal the friction and wear mechanism of the friction pair and complete the selection of brake pads.The main contents of this thesis are as follows:(1)Based on the similarity principle,the related scaling parameters are determined according to the scaling test simulation criteria,referring to the 1:1 bench test,the scaling experiment plan is proposed,complete the structure design and process of the scaling test piece.(2)The scale test will be carried out of the friction pair of imported disc and the friction pair of independent disc/imported brake pad(928W),compare and analyze the average friction coefficient,instantaneous friction coefficient,brake temperature rise,and wear rate of the two friction pairs.The results show that the performance difference between the two friction pairs is small.The friction coefficient of domestic aluminum alloy discs is stable at 0.38-0.41.SEM and EDS were used to analyze the surface morphology and element distribution of the brake parts,revealing the friction and wear mechanism of the friction pair.(3)A comparative test study was carried out on the three synthetic brake discs,928 W,SDTY,and YCBM.The experimental results show that the friction pair of the autonomous disc/SDTY brake pad decreases with the increase of the initial braking speed;the friction coefficient of the friction pair of the autonomous disc/YCBM brake pad decreases and the wear rate is higher.The friction pair of autonomous disc/928 W brake pad has good matching.Through SEM and EDS analysis,the reasons for the different friction characteristics of the three friction pairs are clarified.The research results of the thesis have certain guiding significance for the selection of friction pairs,which can further enrich the friction and wear theory of aluminum matrix composites,and also provide a certain theoretical basis for accelerating the domestic application of aluminum alloy brake discs in China. |
PDF Full Text Request