受集中对称冲击刚塑性圆拱的变形分析

The rigid-plastic deformation analysis of a circular arch subjected to the symmetrical impact of a concentrated mass

本文采用刚塑性假定和拱轴线不可伸长的假设,考虑塑性铰的移动,对受集中质量对称撞击的固支深圆拱的动力响应进行分析。由于把问题简化为一个自由度系统的运动,使得整个运动过程可以较方便地计算出来。计算结果表明,深圆拱的动力响应特性不同于悬臂梁,移行铰不可能到达拱脚,输入的能量全部消耗在塑性铰的移动过程中。结构的响应时间和撞击点的最终位移随撞击物与拱之质量比的增加而增大。

In this paper, the problem of a thin circular arch, with clamped ends, subjected to symmetrical impact by a concentrated mass, is investigated on the basis of rigid-perfectly plastic and inextensible assumptions. This analysis takes account of the travelling of plastic hinges. In fact, the model of the dynamic deformation is a five-hinge one. This system is of onedegree-of-freedom. The analysis indicates that the charactersistics of the dynamic response of circular arches is not similar to that of cantilever beams, because the travelling hinges cannot reach the base of the arch. The response time and the final deflection of the impinged point increase with the mass ratio α.