| The friction coefficient of the friction pair affects the braking power during the train braking process,resulting in temperature changes on the disc surface.On the contrary,the friction coefficient is the reflection of the material performance,and the temperature affects the change of material performance.There is an interaction between the friction coefficient and the temperature.Therefore,it is instructive to understand the law of the mutual influence of friction coefficient and disc temperature for understanding theforce-energy conversion during the braking process.In this paper,aiming atthe friction pair composed of copper-based powder metallurgy brake pads and forged steel brake disc,adopting the method of combining ADINA software numerical simulation and train scaling test bench,the relationship between the friction coefficient and the temperature of thebrake disc is established at initial speeds of 80,120,160 and 200 km/h,and pressures of 0.5,0.7 and 0.9 MPa.The numerical simulation results show that:(1)The temperature of the brake disc is positively correlated with thefriction coefficient,and the initial braking speed increases,the greater influence of the friction coefficient on the disctemperature.When the braking pressure is 0.5 MPa and the initial braking speeds are 80,120,160,and 200 km/h,the friction coefficient increases by 0.01,the peak temperature increase by 0.5°C,1.5°C,2.4°C,and 5.9°C,respectively.(2)The influence degree of the friction coefficient on the disc temperature increase with braking pressure.When the initial braking speed is 160 km/h and the braking pressure are 0.5,0.7 and 0.9 MPa,the friction coefficient increases by 0.01,the peak temperature increase by 2.4°C,2.7°C,and 4.7°C,respectively.(3)The influence degree of the friction coefficient on the disc temperature is mainly reflected in the early and medium stage of braking,and its influence on the maximum temperature of the disc surface is greater than that of the average temperature.The initial braking speeds increased from 80 km/h to 200 km/h,the friction coefficient increased by 0.01,the maximum temperature on the disc surface increased by 1.4°C and 6.6°C,while the average temperature increased by 1.2°C and 3.6°C,respectively.The test results of the braking show that:(1)There is no obvious correlation between the peak temperature of the disc surface and the friction coefficient.The reason may be that the contact state of the friction pair has a higher influence on the peak temperature than the friction coefficient.There is a correlation between the friction coefficient and the average temperature,and the average temperature increases with the increase of the friction coefficient.(2)The average temperature difference of the friction pair with the largest friction coefficient difference increases from 5℃ to 24.9℃ when the initial speed increased from 80 km/h to 200 km/h.The brake pressure increased from 0.5 MPa to 0.9 MPa,and the difference between them increases from 32.4℃ to 32.9℃.The comparison between the test and simulation results shows that:The temperature of the brake disc measured in the test is higher than that of the simulation.The initial braking speed was increased from 80 km/h to 200 km/h,the maximum difference between the highest temperature on the disc surface between the test and the simulation increased by 60°C,and the maximum difference of the average temperature increased by 56°C.The brake pressure was increased from 0.5 MPa to 0.9 MPa,the maximum difference between the highest temperature on the disc surface of the test and the simulation increased by 15°C.The reason for the temperature deviation between the test and the simulation is that there is non-uniform contact on the friction surface during the test.The non-uniform contact on the friction surface causes the local temperature to be higher than the simulation value. |
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