基于离散元法的爆炸荷载作用下钢框架倒塌模拟

COLLAPSE SIMULATION OF STEEL FRAME UNDER BLAST LOADS BASED ON DISCRETE ELEMENT METHOD

在杆系结构弹性离散元(DEM)方法基础上,进一步发展了可考虑截面塑性开展的DEM纤维本构模型,构建了构件断裂模拟算法,并将该方法应用于钢框架结构在爆炸荷载作用下的动态响应和倒塌破坏全过程模拟。结果表明:纤维模型可以考虑截面塑性开展以及损伤演化过程,断裂算法能有效地模拟构件的失效过程及破坏模式;在爆炸荷载作用下,边柱先于中柱失效,且钢柱产生了不可恢复的塑性变形直至断裂,最终丧失承载力导致钢框架发生整体倒塌。该方法为今后研究大型或超大型杆系结构的大变形、材料非线性以及构件断裂等复杂力学行为提供了一种新的数值分析手段。

Based on the discrete element method（DEM） for elastic analysis of member structures,the DEM fiber constitutive model which considered the plasticity developing of cross-section was further proposed,and then the fracture simulation algorithm of members wass established. The presented method was used to apply the whole collapse simulation and structural dynamic response of steel frame structure caused by the blast load. The results showed that the DEM fiber model was able to consider the process of the plasticity developing and damage evolution of cross-section. Besides,the fracture algorithm could effectively simulate the failure process and fracture modes of structural members. Under the blast load,the side column of steel frame occurred failure before the middle column. After that,the integral collapse of the frame,which was subjected to the blast load,was mainly caused by the loss of bearing capacity of the steel column with irrecoverable plastic deformation and until the fracture. The study could provide a new numerical analysis method for further investigation of the complicated mechanical behavior, which including large deformation, material nonlinearity and fractures-of large or super-large member structures.