基于SPH方法铁路车轴遭受道砟撞击的数值模拟

基于非线性有限元软件LS-DYNA及其提供的SPH（smoothed particle hydrodynamics）算法，建立了高速铁路车轴遭受道砟撞击的计算分析模型，考察了不同撞击速度、道砟形状和尺寸，以及撞击角度工况下车轴的动态响应。给出了撞击力和车轴受撞击处变形的响应特征，分析了车轴最大残余变形与撞击力峰值之间的关系，探讨了不同工况下车轴的撞击损伤规律。结果表明，撞击力峰值和车轴变形（包括瞬态变形和残余变形）均随着撞击速度、道砟直径和撞击角度的增大而增大，车轴最大残余变形与撞击力峰值呈近似线性增大关系，车轴的量纲一压痕深度（残余变形）与吸收冲击能平方根成线性关系。

A numerical simulation of railway axles subjected to ballast impact based on SPH method

Based on the nonlinear finite element software LS-DYNA and smoothed particle hydrodynamics (SPH) method,a computational model of high-speed railway axles subjected to ballast impact was built.Influences of impact velocity,ballast shape and size,and impact angle on the dynamic response of axles were examined.The response characteristics of the impact force and the deformation at the impact point were given,and the relationship between the peak impact force and the maximum residual deformation of the axle was also analyzed.Finally,the impact damage regularity of the axle under different conditions was also explored.Numerical results show that both the peak impact force and the deformation of the axle,including both transient and residual deformation,increase with the increase of initial impact velocity,ballast size and impact angle,respectively,and an approximately linear increase between the maximum residual deformation and peak impact force is found.Besides,the normalized indentation depth (residual deformation) of axles increases linearly with the square root of impact energy.