子弹撞击作用下固支浅圆拱的弹塑性动力响应

基于大变形动力学微分方程并利用有限差分离散分析，研究了子弹撞击作用下固支浅圆拱的弹塑性动力响应。通过对响应不同时刻内力分布特征的分析，阐明了圆拱的响应模式和变形机制。研究表明，弹塑性响应过程可分为六个阶段。在响应早期，拱的变形以塑性弯曲挠动由撞击点向拱根部传播为主；在响应后期，则主要以轴力主导下的轴向拉伸变形为主。在高速撞击下，塑性弯曲挠动的不均匀性可以引起浅拱的反向弯曲变形。固支浅圆拱的动力响应对撞击速度的某个变化范围非常敏感，在此范围内，撞击速度的较小增加可以导致响应的很快增长，但动力响应随撞击速度连续变化，未发生突然的跳跃失稳。本文中计算结果同实验数据吻合较好。

Elastic-plastic dynamic response of a fully clamped shallow arch subjected to projectile impact

Based on large deformation dynamic equation and finite difference method, the elastic-plastic dynamic responses of a fully clamped shallow arch subjected to projectile impact were studied numerically. Through analyzing the instantaneous distribution of the internal forces during early time response, the elastic-plastic deformation mechanism and mode were illustrated. The deformation mode consists of six phases. In the early phase of impact, the propagation of plastic bending deformation from the impact point to the root of arch dominated the deformation mode. While in the later phase, the deformation of axial tension governed by the axial force was dominant. Under the high-velocity projectile impact, the uneven plastic bending deformation can cause the arch to produce reversed flexural deformation. It can also be seen that the dynamic response of arch was very sensitive to a certain range of impact speed. In this range, tiny increase of initial projectile velocity can cause rapid increase of displacement. However, variation of dynamic response with impact speed was continuous without abrupt lose of stability. Numerical results were in good agreement with the experimental results from literature 5].