车桥耦合振动的拱桥吊杆应力冲击系数分析

Numerical Studies of Suspenders′Stress Impact Factor of Train and Arch Bridge Coupled Systems

基于车桥耦合振动理论及地基微波雷达现场试验,研究了高速铁路拱桥的吊杆应力冲击系数。列车和轨道-桥梁模型分别采用刚体动力学和有限元方法建立,两子系统间通过轮轨线性Hertz接触理论实现耦合。采用地基微波雷达对吊杆两端位移进行测试,分析得到桥梁动力特性、吊杆应力时程及其冲击系数。对比地基微波雷达试验数据,验证理论模型的正确性,并基于该模型分析车速、单双线行驶和轨道不平顺对吊杆应力冲击系数的影响规律。结果表明:吊杆应力冲击系数随车速的增加而增大,当车速为300km/h时车桥共振导致吊杆应力冲击系数显著增大;德国低干扰轨道谱样本对吊杆应力冲击系数影响较小,但随着轨道平顺性的劣化,吊杆应力冲击系数显著增大。

Based on the vehicle-bridge coupling vibration theory and the field test of ground-based microwave radar,the stress impact coefficient of suspender of high-speed railway arch bridge is studied.The train and track-bridge are modeled by multi-rigid-body dynamics and finite element method,respectively,and the train-track-bridge coupled system model is established based on the equivalent Hertz linear wheel/rail contact model.The displacements of the top and bottom of the suspenders are tested simultaneously by the ground-based microwave radar system.The dynamic characteristics of the bridge,the time-history of stress and the stress impact factor of suspenders are obtained.The experimental data of ground-based microwave radar are compared to verify the correctness of the theoretical model.Based on the model,the influences of driving speed,single or double line driving and track irregularity on the stress impact factor of the suspenders are analyzed.The results show that the stress impact factor of suspender increases with the increase of vehicle speed.When the speed is 300 km/h,the stress impact factor of the suspender increases significantly due to the resonance of the axle.Due to the low static stress of suspender caused by train load,the impact factor of suspenders during single-line driving is larger than that of the double line.The German low-interference orbit spectrum sample has little effect on the stress-impact coefficient of the suspenders,but the stress impact factor increases significantly with the deterioration of track smoothness.