近爆作用下钢筋混凝土板动态破坏的数值模拟研究

Numerical simulation for dynamic failure of a reinforced concrete slab under close-in explosion

当爆炸在结构构件表面发生时,产生的冲击波将会对结构构件造成损伤和破坏,而准确预测潜在的爆炸对结构构件造成的损伤是进行重要建筑物和防护结构抗爆设计的基础。为研究近爆作用下钢筋混凝土板的抗爆性能,采用AUTODYN软件建立了混凝土和钢筋的三维分离式实体模型,数值模型考虑了应变率对钢筋和混凝土材料动力本构特性的影响以及炸药-空气-结构之间的流固耦合相互作用,分析了不同炸药量作用下钢筋混凝土板的损伤机理和破坏特征,合理展现了钢筋混凝土板从混凝土开裂、碎片形成、部分钢筋屈服断裂到板局部震塌的动态演变过程。随着炸药量的增大,钢筋混凝土板的破坏模式逐渐由整体弯曲破坏转变为局部的冲切破坏。

When an explosion occurrs at surfaces of structural components,the tremendous shock wave leads to structural damage and destruction,thus correctly predicting damages caused by any potential explosion is essential to design of important buildings and protective structures.In order to identify the anti-explosion performance of a RC slab under close-in explosion,using commercial hydrocode AUTODYN,a three-dimensional solid model including explosive,air and a RC slab with concrete and reinforcing bars separated was created,sophisticated concrete and reinforcing bar material models considering strain rate effects and appropriate coupling at air-solid interface were used to simulate the dynamic response of the RC slab,the corresponding damage mechanisms and failure modes were analyzed under different explosive charge.The dynamic evolution process of the RC slab from cracking and break-up of concrete,yield and rupture of reinforcing bar to local perforation was observed realistically,and with increase in explosive charge,the failure mode of the RC slab gradually changed from overall flexure failure to local punching failure.