The saturated impulse phenomenon, which may occur in a hollow beam with a circular cross-section, is examined when a rectangular pressure pulse loading is applied uniformly on the upper surface of the beam. A simplified 2DoF model of the dynamic response of a relatively long circular hollow section beam is developed to explore the role of the local and global deformations build up simultaneously during the beam response. In order to simplify the analytical formulation, the elastic deformations of the hollow beam are neglected, and a rigid-plastic method of analysis is applied. Finite element simulations using an elastic, perfectly plastic material model are carried out to verify the proposed analytical model and to reveal the influence of the elasticity on the beam response. The limit of the pressure pulse loading, beyond which saturated impulse is not defined for a hollow beam, is obtained numerically. The responses of hollow beams with lengths between 800 and 1200 mm, radius of 40 mm and several wall thicknesses are analysed. It is observed that the proposed 2DoF model can predict satisfactory the local and global saturated deflections while the saturated pressure pulse duration is underestimated due to the disregard of the stored elastic energy in the beam. It is suggested that the analytically predicted saturated impulse can be used as a lower bound estimate for the saturated impulse for a given beam geometry.

研究了当矩形压力脉冲载荷均匀施加在梁上表面时，可能发生在圆形截面空心梁中的饱和脉冲现象。开发了一个相对较长的圆形空心截面梁的动态响应的简化 2DoF 模型，以探索在梁响应过程中同时建立的局部和全局变形的作用。为了简化分析公式，忽略空心梁的弹性变形，并采用刚塑性分析方法。使用弹性、完美塑性材料模型进行有限元模拟，以验证所提出的分析模型并揭示弹性对梁响应的影响。压力脉冲负载的极限，对于空心梁，超过这个饱和脉冲没有定义，可以通过数值获得。分析了长度在 800 到 1200 毫米之间、半径为 40 毫米和几种壁厚的空心梁的响应。观察到，所提出的 2DoF 模型可以预测令人满意的局部和全局饱和偏转，而由于忽略了梁中存储的弹性能量，饱和压力脉冲持续时间被低估了。建议分析预测的饱和脉冲可以用作给定梁几何结构的饱和脉冲的下限估计。观察到，所提出的 2DoF 模型可以预测令人满意的局部和全局饱和偏转，而由于忽略了梁中存储的弹性能量，饱和压力脉冲持续时间被低估了。建议分析预测的饱和脉冲可以用作给定梁几何结构的饱和脉冲的下限估计。观察到，所提出的 2DoF 模型可以预测令人满意的局部和全局饱和偏转，而由于忽略了梁中存储的弹性能量，饱和压力脉冲持续时间被低估了。建议分析预测的饱和脉冲可以用作给定梁几何结构的饱和脉冲的下限估计。