Study On The Influence Of Section Shape On Dynamic Response Of Steel Members Under Blast Load

At this stage,domestic and international terrorist attacks and accidental safety production explosions occur frequently.Industrial and civil building structures,especially the increasingly widely used steel structures,are increasingly valued by engineering designers for their antiknock performance during the design process.The equivalent single degree of freedom system analysis method has the advantages of simple calculation and dynamic characteristics of reactive members,and is widely used in most foreign antiknock design specifications.However,the existing equivalent single degree of freedom system analysis method does not consider the influence of the section shape on the dynamic response of steel members.According to the numerical simulation results,the dynamic response of steel members with similar moments of inertia but different section shapes under blast loading is quite different.It is urgent to propose a method for quickly evaluating the maximum displacement response under the blast load for steel members with different section shapes,and further guides the engineering anti-explosion design.In this paper,steel members with different section shapes are taken as research objects,and theoretical analysis and numerical simulation analysis are carried out respectively.The main research contents and conclusions are as follows:(1)Using the theoretical analysis method,the displacement time history curves of steel members with different section shapes under blast load are obtained.For steel beams or steel columns with different section shapes but similar moments of inertia,the displacement time-history curves under blast loading are similar,and the maximum difference of maximum displacement is less than 8%.(2)Considering the interaction between the explosion shock wave and the components with different section shapes,the finite element model is established,and the dynamic response of steel members with different section shapes is simulated systematically.The reasons for the difference of response are analyzed.In the numerical simulation,the maximum displacement of the members of different section shapes differs by about 2 times.(3)Based on the numerical simulation results,the theoretical analysis results are corrected,and the calculation formula of the correction coefficient is obtained by fitting.For H-section steel members with the same section width and similar moment of inertia,the section parameters are proposed for the section characteristics.Further,the correction coefficient obtained by the standard H-section correction formula is corrected by the section parameter.Taking the scale distance and the self-vibrating circle frequency as independent variables,the formula for calculating the maximum displacement correction coefficient is obtained.The correction coefficient calculation formula is used to predict the maximum displacement of the steel members,and the differences between the predicted values and the numerical simulation results are less than 10%.(4)The effects of explosion shock waves with different incident angles on the dynamic response of square-section and H-section members were further studied.For the parameter changes and response differences caused by different incident angles,a cause analysis is performed.