| In recent years,terrorist attacks and explosion accidents have occurred frequently.The collapse of the structure caused by the explosion has seriously threatened the lives of people.Explosion impact is powerful,instantaneous and local.Local failure of structural members or beam-column connections can result in collapse of the structure.Therefore,it is important to study the anti-explosion performance of structure the beam-column joints.The explicit finite element software LS-DYNA is used to study the dynamic response of steel frame under internal explosion.Based on the deformation characteristics and internal force distribution of the steel frame,a simplified model of beam-column connection is proposed.Parametric analysis of the dynamic response of the internal explosion impact was studied.The research contents are as follows:(1)Proper element type,material parameters,and fluid-solid coupling algorithm is used to simulate the dynamic response of steel frame subjected to internal explosion.History of displacement,velocity and acceleration of representative nodes at different positions are analyzed.The result shows that the deformation of the beam-column connections under the impact load is local and weak transformation.(2)By changing the magnitude of the explosion impact load,the sensitivity of the frame structure deformation and internal force distribution to the explosive equivalent increment is analyzed.Transfer coefficient was put forward to describe the transfer efficiency of internal force in members.(3)The beam-column joint is the simplified into combination of beam-column component and constrained spring at the end.The blast impact load is simplified The anti-explosion performance of beam-column joints with different parameters is studied: ratio of column-to-wall flange thickness,column lateral stiffeners,column web thickness at panel zone,and axial compression ratio.The results show that increasing the thickness of the beam,column flange,transverse stiffener and thickness of panel zone can alleviate the local buckling in the web and flange of column,and reduce the deformation of the joint;the column axial pressure ratio has little effect on the stress distribution and deformation of connection.According to the results,the existing beam-column connections designed according to the seismic requirements will be damaged lightly in the ordinary human bomb attack,but the larger TNT equivalent explosive explosion will occur a large deformation and stress.The explosion resistance performance of connection should be further studied. |
