轨下垫板刚度的时变特性及其影响研究

以WJ7-A型轨下垫板为对象,测试轨下胶垫刚度随服役时间的变化,分析垫板刚度的时变特性;然后以此为基础,建立车辆-轨道垂向耦合动力学模型,研究轨下胶垫时变特性对轮轨随机振动响应的影响规律。研究结果表明:随着服役时间的增长,轨下橡胶垫板的刚度将增大,2年后垫板刚度的增幅为13.91%;随着运营时间的增长,车体振动加速度变化微弱;轮轨力及扣件力的第二主频幅值增大并向高频移动,且扣件力变化更显著,线路运营2年时间后,扣件力第二主频向高频移动7.4 Hz,幅值增幅达到53.80%。建议定期抽样测试轨下胶垫刚度并及时更换性能老化垫板,降低轮轨垂向力和扣件力。

Study on Time Variant Characteristics and Effects of Rail Pad Stiffness

With respect to WJ7-A rail pad,the change of rail pad stiffness with service time is tested and the time variant characteristics of rail pad stiffness are analyzed. The vehicle-track vertical coupling dynamic model is established based on the test results,the effects of time variant characteristics of rail pad stiffness on the random vibration responses of wheel-rail system are studied. The results show that the stiffness of the rail pad increases with the increasing of the service time,and the increase amplitude is about 13. 91% after 2 years. The vibration acceleration of vehicle fluctuates slightly with the extension of the operating time. The second dominant frequency of wheel-rail force and fastening force increase and move to a higher frequency and the fastening force changes significantly. After two years of operation,the second dominant frequency of fastening force moves by 7. 4Hz to a higher frequency,and the amplitude increases by 53. 80%. In order to reduce wheel-rail force and fastening force,it is recommended to test regularly the stiffness of the rail pad by sampling and replace the aging pads timely.