直杆碰撞刚性壁弹塑性动力后屈曲有限元分析

利用显式动力学有限元方法对直杆弹塑性动力后屈曲进行了分析，模拟了直杆轴向碰撞动力屈曲的变形及发展过程。分析中在直杆碰撞端局部临界屈曲长度范围内引入半正弦波形式的初始缺陷，计算结果与文献中的实验数据获得了很好的一致。分析结果表明，随着碰撞过程中所产生的应力波逐渐向前传播，后屈曲变形过程中所呈现的多个半波形式的高阶屈曲模态由初始具有单个半波形式的简单屈曲模态迅速演变而成。分析结果同时也揭示了直杆动力屈曲变形发展的机理，以及轴向应力波和屈曲变形的相互作用规律。

Finite element analysis for elastic-plastic dynamic postbuckling of bars subjected to axial impact

By use of explicit dynamics finite element method,the elastic-plastic dynamic postbuckling of bars subjected to axial high-velocity impact was studied.In order to initiate the buckling mode,the bar was given a small initial imperfection in the form of half of a sine wave near the impacted end.Results obtained in the present study agree well with the experimental data in the reference.As the axial compressive waves propagate forward,it is found that the initial buckling deflection with one half-wave,occurring near the impacted end,quickly develops into the higher postbuckling mode with several half-waves.The present investigation reveals the mechanism of growth and spread of buckling deformation in the bar and the interaction between the axial stress wave and the buckling deformation in impact process.