爆炸冲击荷载作用下拱结构的弹塑性动力响应研究

采用数值模拟方法,研究拱结构在爆炸冲击荷载作用下的弹塑性动力响应。结构动力屈曲临界荷载由B-R 准则判定。研究结果表明:拱结构的动力响应过程可划分为4 个典型阶段,即弹性振动阶段、弹塑性稳定振动阶段、反直观动力响应阶段和压溃破坏阶段,拱结构反直观动力响应是其发生动力屈曲以后处于不稳定平衡状态中的一种动力响应模式;爆炸冲击持续时间越长,拱结构动力屈曲临界荷载越小;当冲击持续时间在某一范围内时,结构发生动力屈曲以后会出现反直观动力响应;爆炸冲击持续时间太长或太短,结构发生动力屈曲以后将不会出现反直观动力响应,即结构一旦发生屈曲就会出现毫无征兆的突然破坏,动力屈曲临界荷载就是动力失效荷载。

Elastic-plastic Analysis on Dynamic Response of Arch Subjected to Explosive Impact

The elastic-plastic dynamic response of arch structure subjected to explosive impact is analyzed with numerical simulation method. The dynamic buckling critical load is determined by B-R criterion. The results show that the process of the dynamic response is divided into the four typical stages: elastic vibration, elastic-plastic stable vibration, counter-intuitive dynamic response and crush failure. The counter-intuitive dynamic response is a mode of the unstable equilibrium after dynamic buckling. The results show that the longer the impact duration is, the smaller the dynamic buckling critical load is. When the impact duration changes in a range, the counter-intuitive response appears after buckling. When the impact duration is too long or too short, the counter-intuitive response will not appear. The sudden destruction occurs as soon as the buckling. The dynamic buckling critical load is equal to the dynamic failure load.