重载货车摩擦缓冲器动力学模型研究

摘要

基于摩擦缓冲器冲击试验数据建立缓冲器多段线性模型，利用附加黏滞摩擦力和附加阻尼力进行理论修正，构建缓冲器多段线性修正模型，利用车辆冲击仿真及反映列车运行工况的三角函数位移激励对缓冲器多段线性修正模型进行验证和分析。计算结果表明：缓冲器多段线性修正模型较常规多段线性模型更接近冲击试验结果；转换速度及外部位移激励的频率会对车钩力尖峰阶段产生影响，转换速度越大或者外部频率越小，车钩力越先进入尖峰阶段，形成的磁滞环就越大，消耗的车辆振动能量越多，后续的车钩力和车辆相对位移就会越小；附加黏滞摩擦力较好地模拟了缓冲器特性曲线的尖峰现象，等效摩擦系数越大，附加黏滞摩擦力越大，车钩力也越大；附加阻尼和车体刚度的共同作用使缓冲器加载曲线与卸载曲线之间平稳过渡，在附加阻尼的修正下，即使缓冲器处于过渡曲线上遇到往复加载和卸载载荷，缓冲器也能形成磁滞耗能环，亦能耗散车辆之间的振动能量。%Piecewise linear model for friction draft gear was built based on the friction draft gear impact test da‐ta .The piecewise linear modification model was built after theoretical modification was made with the addition‐al viscous friction force and the additional damping force .The vehicle impact simulation and vehicle relative dis‐placement excitation described by trigonometric function which reflected train operation conditions were used to verify and analyze the piecewise linear modification model .The results indicated as follows :The simulation of modified piecewise linear model was closer to the results of the impact test than the conventional piecewise line‐ar model .Transition velocity from kinetic to static friction and the external displacement excitation frequency had an effect on the nonlinear peak of coupler force . Higher transition velocity or lower external frequency caused the coupler force to switch to the nonlinear peak more quickly ,and to produce larger hysteresis loop , more vibration energy and smaller subsequent coupler force and relative displacement .The additional viscous friction force simulated the nonlinear peak of the characteristic curve of the draft gear well .The larger equiva‐lent friction coefficient led to a larger additional viscous friction force and coupler force .The combined effects of the additional damping and vehicle structure stiffness resulted in smooth transition between loading curve and unloading curve of the draft gear .Under the modification of additional damping ,the draft gear formed a hyster‐esis loop even if the draft gear suffered loading and unloading on the intermediate curve ,and dissipated the vi‐bration energy between the vehicles .