| At present,domestic EMUs mainly use disc brakes,and the EMU brake pads are the key components of the disc brakes and form friction braking with the brake disc.During the braking process,the EMU is in a high-speed and heavy-load condition,and a large amount of friction heat will be generated on the surface of the brake pads,under the combined action of force and heat,surface contact stress is formed,and then wear occurs,which will affect the braking performance.Therefore,analyzing the friction and wear performance of the EMU brake pads and predicting the life of the brake pads is of great significance to ensure the safety of the EMU operation.Taking the EMU brake pad as the research object,this paper studied the heat,stress and wear laws of the brake interface,a life prediction system for the brake pad is established.The main research contents are as follows:(1)Based on HY203F high-power braking system vibration performance test platform,infrared thermometer,and other signal collectors,carry out friction and wear test.The changes of temperature and friction coefficient in the braking process and their reasons were analyzed,and the influence of the braking parameters on the temperature and friction coefficient of the friction pair and their reasons were studied by using the single variable method;Based on the three-dimensional topography measuring instrument,the surface wear morphology of the brake pad was scanned,and the distribution law of the surface wear of the brake pad was studied and analyzed.(2)The thermal-mechanical coupling model of the disc brake was established by the direct coupling method,and the distribution law of the thermal-mechanical coupling field during the brake pad braking process was analyzed,and the validity of the model was verified.The influence of braking parameters on the thermal-mechanical coupling of the brake pads was studied by using the single variable method.The results show that the maximum temperature of the brake pad was proportional to the size of the braking parameters,the initial braking speed has a great influence on the stress-strain peak value during the braking process,and the braking pressure has a great influence on the stress-strain peak value at the end of braking.(3)Based on the thermal-mechanical coupling model,combined with adaptive mesh technology and wear theory,the secondary development of subroutines was carried out,the surface wear calculation of the brake pad was realized,and the evolution law and distribution state of the brake pad wear were simulated.The influence of braking parameters on the wear of the brake pads was studied by the single variable method.The results show that with the increase of the initial braking speed and the braking pressure,the wear depth of the brake pad increases and the wear change rate decreases.(4)According to the wear simulation results of brake pad,a database of the corresponding relationship between wear and braking parameters was established,and the wear prediction model by fetching the data through the BP algorithm was established.Combined with the operation data of the EMU,the corresponding relationship between the wear amount of the EMU brake pad and the mileage was established.Using the wear prediction model and the corresponding relationship between the wear amount and the mileage,a life prediction system for the brake pads of the EMU was designed.The results show that the prediction system has high accuracy and can be used for life prediction of brake pads.In this paper,the heat,force and wear of disc brakes in the braking process were studied,the influence of braking parameters on the heat,force and wear of the brake pads was revealed,a life prediction system for the brake pads of the EMU was designed,provides a reference for the design and operation and maintenance of the EMU brake pads. |
PDF Full Text Request