轨道结构落锤冲击的数值模拟方法

Numerical Simulation Method for Track Structure under Drop Impact

轨道结构落锤冲击数值模拟的重点和难点是建立落锤与钢轨间碰撞力的计算式。运用构造函数法,考虑钢轨和落锤的弹性模量、落锤直径、钢轨踏面直径和接触面粗糙度的影响,建立落锤与钢轨间碰撞力关于这二者趋近量的计算式。运用Fortran语言,采用预测—隐式积分法,编制求解落锤和轨道结构耦合动力方程的计算程序。根据同一轨道结构的落锤冲击碰撞力相等的原则,采用LS-Dyna软件和自编程序进行仿真计算,确定碰撞力计算式中的系数。室内实尺模型试验实测与数值模拟计算的钢轨、轨枕和道床的振动加速度在相同落高下基本保持一致,验证了该数值模拟方法的可靠性。

The difficulty and emphasis for the numerical simulation of railway structure under drop impact is to establish the formula to calculate the impact force while drop hammer contacting rail.The formula for the approach of the impact force between contact surfaces was obtained by structural function method considering the influences of such factors as,the elastic modulus of rail and drop hammer,the diameters of drop hammer and rail tread,and the roughness of contact surface.With the computer language of Fortran,the corresponding computer program for solving the dynamic coupling equations of drop hammer and track structure was worked out by forecast-implicit integration algorithm.In accordance with the principle that the impact force of drop hammer was equal for the same track structure,simulation was carried through by LS-Dyna software and self-compiled program to determine the coefficients in the formula for impact force.The measured results obtained by the full-scale model test in the lab for the vibration accelerations of rail,sleeper and ballast bed basically agree with those obtained from numerical simulation,which has verified the reliability of proposed numerical simulation method.