Numerical analysis on damage and collapse process of steel frame structures under blast loads

The traditional numerical methods for simulating the dynamic response and progressive collapse of entire structures require complicated modeling work and extremely time-consuming calculation,resulting in their rare application.In this paper,a new method for the numerical analysis of entire structural model is proposed,which is directly employed to analyze the dynamic response and damage patterns of steel frame structures subjected to blast loads.According to the new method,the simulation process is divided into two steps.Firstly,the propagation of blast wave in air is simulated by the Remap tool of AUTODYN.The numerical gauges are used to record the pressure time history on the surfaces of structural members,e.g.columns and beams.Secondly,a refined finite element model of steel frame structure is created,and the blast load is applied on the surfaces of members according to the measured data in the first step for further analysis of structural response and damage procedure using the explicit solver of LS-DYNA.The whole simulation of structural response of a typical steel frame structure caused by blast load is carried out.The numerical results show that the steel frame structure is capable of resisting blast load,which is adequate to survive a medium-scaled(up to 1 000 kg equivalent of TNT charge) out-door explosion.Severe progressive collapse or local damage as downfall of secondary beam is likely to be induced by a huge-scaled blast load case(more than 1 500 kg equivalent of TNT charge).