圆柱壳受不对称径向冲击时的塑性动力屈曲分析

本文发展了Lindberg、Duffey等人的思想,考虑不对称冲击下圆柱壳的塑性动力屈曲问题,旨在研究内凹变形与屈曲的关系。用能量法导出了不对称基本变形的微分方程,近似地将之与对称情形下屈曲扰动控制方程联合,构成一个初值问题,然后进行数值求解。考虑了壳厚变化,放弃了屈曲过程中速度保持不变的假定(对称情形中采用)。本文的研究结果很好地解释了高速冲击时倒塌模式上无屈曲波形,屈曲波形遍布加载范围内且并不明显减弱,局部冲击临界速度高于对称情况形下临界速度等许多实验与已有的分析结果,从而明确了屈曲在塑性动响应中的地位。

Dynamic Plastic Buckling Analysis of Cylindrical Shell subjected to Asymmetric Impulsive External Loads

A buckling theory originally developed by Lindberg and Duffey for collapsing ring and shells is extended to account for asymmetric impulsive external loads. The relation of the inward deflection and the dynamic plastic buckling is studied. The differential equation of motion of the inward deflection is obtained by energy method and consisted of a general initial value problem along with the perturbed equation of axisymmetric buckling and the initial values. The assumption of unchanging inward shell velocity is removed and the thickening is accounted. We found that the buckling growth can be limited by the inward deflection at either low or high velocities, maximum imperfection growth appears in an intermediate velocity region, the asymmetric impulse threshold is higher than that of uniform buckling produced by an axisymmetric impulse. Many experimental phenomenon of cylindrical shell subjected to asymmetric impulse is also discussed by the theory of this paper.