利用细长杆端部受冲击时弹塑性应力波的传播规律及加卸载规律 ,建立了梁的弹塑性屈曲方程 ;通过方程求解 ,将梁的动力屈曲划归为分叉问题并给出了分叉条件 ,并由分叉条件得到了屈曲临界力和模态 .数值结果表明 ,杆的动力屈曲不仅与材料及结构参数有关 ,且与冲击时间有关 . The elastic-plastic buckling equation of the beam is established by using the propagation laws of the elastic-plastic stress wave and the loading and unloading laws when the end of the elongated rod is impacted. By solving the equations, the dynamic buckling of the beam is classified as the bifurcation problem Fork conditions, and the buckling critical force and modal are obtained by the bifurcation condition.The numerical results show that the dynamic buckling of the rod is not only related to the material and structural parameters, but also to the impact time.