长持时爆炸冲击波作用下钢梁动力响应分析

大规模爆炸时引起的长持时平面爆炸波会造成结构的整体破坏，这与接触爆炸或近场爆炸的破坏模式有显著差异，但相关研究不多。为研究长持时冲击波作用下钢梁的动力响应，首先基于耦合欧拉-拉格朗日方法建立了大型数值激波管模型，然后采用该数值激波管得到作用在钢梁上的反射超压时程，最后通过显示动力学方法研究了冲击波入射方向、持时、超压等参数对钢梁破坏模式的影响规律。结果表明：本文提出的数值激波管模型能较好的模拟长持时爆炸波的绕射现象，可得到可靠的反射超压和冲量时程；随着冲击波入射角度的增加，简支钢梁跨中位移增大；冲击波超压峰值相同时，随着持时的增加，简支梁跨中的最大位移有增大的趋势，而最大位移的增长速率则会变缓；简支钢梁在长持时爆炸冲击波作用下容易发射受弯破坏，而梁跨中翼缘板会出现局部屈曲现象。

Dynamic responses analysis of steel beam under long duration explosion wave

The large-scale explosive blast waves caused by a major explosion can result in overall structural damage, which is significantly different from the damage pattern caused by contact or near-field explosions. However, there is limited research on this topic. In order to study the dynamic response of steel beams under the action of long-duration shock waves, a large-scale numerical shock tube model was established based on the coupled Euler-Lagrange method. Then, the reflected overpressure time history acting on the steel beam was obtained using this numerical shock tube model. Finally, the influence of shock wave incident direction, duration, overpressure, and other parameters on the damage modes of the steel beam was studied using the Lagrangian dynamics method. The results showed that the proposed numerical shock tube model can effectively simulate the diffraction phenomenon of long-duration explosive waves and provide reliable reflected overpressure and impulse time histories. With increasing incident angle of the shock wave, the displacement at the mid-span of the simply supported steel beam increases. When the peak overpressure of the shock waves is the same, with the increase in duration, the maximum displacement at the mid-span of the simply supported beam tends to increase, but the rate of increase in maximum displacement slows down. The simply supported steel beam is prone to flexural failure under the action of long-duration explosive shock waves, and localized buckling occurs in the flange plate at the mid-span of the beam.