数值模拟轴向冲击下直杆的动态响应

Numerical Simulation for Analysis of Dynamic Response of Unbent Bar During Axial Impact

使用数值方法模拟了弹性和弹塑性杆受到纵向冲击的全过程,通过计算分析了荷载大小不变,施加速率不同时直杆的动态响应及有无率相关情况下杆的响应。发现:对于弹性直杆,轴向冲击荷载大小不变,加载速率的改变对加载点位移和加速度影响较大,而对加载点的速度峰值影响不大,加载速率越大,加载点的位移越小,加速度越大;对于弹塑性杆,加载速率越大,加载点的位移和速度峰值越小,结构的吸能比却越大。另外,对于某些应变率敏感材料,材料的率相关性对冲击载荷下的动态响应的影响也是值得关注的。

In the paper,the dynamic axial response of elasto- plastic bar with one end fixed is simulated using numerical method. The elastic and elasto-plastic loads with different veloctities are obtained. The solutions of the strain rate dependence and stain rate independence are compared. The calculation results show that ：for the elastic unbent bar,when the impact load is constant, the speed of the load affects the distance and the acceleration of the free end of the bar but has no effect on the peak value of the velocity at the free end, the larger speed of the impact load, the smaller distance and the larger acceleration at the free end. For the elasto-plastic bar, when the impact load is constant, the larger speed of the load, the smaller the peak value of the distance and the velocity at the free end, but the higher ratio of the energy- absorption. In addition ,for some materials which are sensitive to the strain rate ,it is important to consider the strain rate dependence.