波浪面对车桥气动特性影响下的车桥系统耦合仿真研究

Joint simulation of vehicle-bridge system with aerodynamic characteristics affected by various wave bottom surfaces

为研究波浪形底面对列车-桥梁气动荷载影响下的车桥系统振动响应,选取平潭海峡元洪水道大桥为研究对象,固定列车车速和风速,采用流体动力学软件Fluent,计算系统在横风作用及不同波浪形底面下列车和桥梁的气动荷载。基于有限元软件ANSYS和多体动力学软件SIMPACK建立三维列车-桥梁联合仿真模型,将得到的气动荷载通过时间激励方式施加到列车-桥梁系统中。研究相同车速和风速在不同波浪重现期下波浪形底面对气动荷载的影响以及车桥耦合振动问题。研究结果表明:底面为平面时,风速剖面近似呈线性增长,且风速梯度显著大于底面为波浪形的工况;底面为波浪面时,各重现期下风场特性差异较小,波谷临近处速度梯度较小,向两侧波峰逐渐增大;风场中不同重现期波浪面的改变会使列车和桥梁的气动荷载的频率、幅值大小发生不同程度的改变;底部为平面时,桥梁的阻力、升力和力矩气动荷载峰值均小于底部为波浪面时的荷载峰值;列车的安全性指标均随着波浪重现期的增大而增大,其中横向力和轮重减载率的增幅较明显,100年波浪重现期下列车头车横向力、减载率和横向加速度分别比无波浪时增大了13.45%、23.08%和37.61%;桥梁跨中横向最大位移与横向最大加速度均随波浪重现期的增大而增大,竖向则变化不大。

Here,to study vibration response of vehicle-bridge system with vehicle-bridge aerodynamic load affected by various wave bottom surfaces,Yuanhong Waterway Bridge in Pingtan Strait was taken as the study object,the train speed and wind speed were unchanged,and the fluid dynamic software Fluent was used to calculate aerodynamic loads of train and bridge under cross wind and different wave bottom surfaces.Based on the finite element software ANSYS and multi-body dynamics software SIMPACK,a 3D train-bridge joint simulation model was established,and the obtained aerodynamic load in the form of time excitation was exerted on the train-bridge system.Effects of wave bottom surface on aerodynamic load and vehicle-bridge coupled vibration under different wave return periods at the same speed and wind speed were studied.The results showed that(1)when wave bottom surface is planar,wind speed profile increases almost linearly,and wind speed gradient is significantly larger than that when bottom surface is wavy;when bottom surface is wavy,the difference of wind field characteristics in each return period is smaller,wind speed gradient near wave trough is smaller,and wave peak gradually increases to both sides;(2)change of wave surface in different return periods in wind field can change frequency and amplitude of aerodynamic load of train and bridge to different degrees;(3)when wave bottom surface is planar,peaks of bridge’s resistance,and aerodynamic loads of lift force and moment are less than those when the wave bottom surface is wavy;(4)safety indexes of train increase with increase in wave return period,in which increases in transverse force and wheel weight reduction rate are more obvious;under 100 year wave return period,transverse force,wheel weight reduction rate and transverse acceleration of train’s head car increase by 13.45%,23.08%and 37.61%,respectively compared with those under the condition of no wave;(5)transverse maximum displacement and transverse maximum acceleration at the middle of bridge span increase with increase in wave return period,but vertical change is little.