考虑闸瓦-轮对-轨道耦合的瞬态接触黏滑特性分析OA

In order to elucidate the formation mechanism of structural damage on the contact surface,the contact characteristics of the brake shoe-wheelset-track system were investigated from the level of stick-slip vibration.According to the typical line situation,a finite element model of the brake shoe-wheelset-track coupling system was established.By executing transient calculations,the stick-slip vibration features of contact surfaces were analyzed,and the causes of surface damages of relevant structures were explored.The structural parameter of the system model was analyzed,serving as a basis for the matching optimization of dynamic parameters.The results show that,for the brake shoe-wheel contact system,the wheelset vibration acceleration is gradually transitioned from longitudinal vibration acceleration dominance to vertical vibration acceleration dominance,the main eigenfrequencies of the longitudinal vibration acceleration are 540 Hz and 616 Hz,and the main eigenfrequencies of the vertical vibration acceleration are 398-426 Hz.The wear areas of the contact surface of the brake shoe are mainly concentrated in the upper top,middle and lower bottom.For the wheel-rail contact system,in the interval of drastic variation of vibration acceleration,the rail vertical vibration acceleration occupies the main part.In the frequency range of 0-1 000 Hz,none of the three directions of the rail vibration acceleration shows obvious eigenfrequency.The rail surface shows significant longitudinal and transverse slips in the initial interval of wheelset operation,with the maximum longitudinal slip amounting to 0.119 mm and the maximum transverse slip amounting to 8.022 mm,which indicates that the braking effect leads to larger slips at the wheel-rail interface.When the parameter is changed,the variation trend of the maximum value of the contact surface slip of brake shoe and rail remains consistent.Increasing the wheelset running speed,brake shoe pressure,coefficient of friction of shoe-wheel and wheel-rail,primary suspension vertical force,and three-direction stiffness of the fastener can contribute to an increase in the maximum value of the contact surface slip,whereas increasing the three-direction damping of the fastener can decrease the maximum value of the contact surface slip.The wheelset running speed,brake shoe pressure,and coefficient of friction of shoe-wheel and wheel-rail have a large effect on the maximum value of the contact surface slip,while the rest of the parameters have a small effect on the maximum value of the contact surface slip.