| With the continuous development of China’s urban modernization,people have more and more demands for various types of buildings.Steel structures have been increasingly applied to the construction of urban modernization because of their good ductility,strong plastic deformation ability and light self-weight,which fully meets the requirements of China’s housing industrialization and sustainable development.In people’s daily life,steel structures are not only affected by various conventional loads,but also by accidental explosion loads.In China,explosions are mainly caused by accidental explosions,which often cause huge property losses and endanger people’s lives.Steel structure and its members will be damaged or destroyed to some extent when impacted by explosion load.The damaged or damaged connection nodes and other local members will lose their bearing capacity,resulting in instantaneous redistribution,causing local members to fall off,and resulting in great deformation of the whole steel structure.Finally the steel structure will collapse continuously due to a series of nonlinear dynamic responses.As a sequence,it is of great theoretical significance and practical engineering reference value to analyze the anti-explosion performance of steel frame beam-column connection.In the present study,the commercial finite element analysis software ANSYS/LS-DYNA is firstly used to introduce the relevant theoretical concepts of explosion.Secondly,combined with relevant experimental simulation,the dynamic response of steel frame beam-column connections under explosion load is simulated and verified to ensure the feasibility of numerical simulation.On this basis,the numerical simulation of steel frame beam-column connections with different connection modes,different explosion distances and different explosive masses is carried out,and the orthogonal test is established and analyzed by the range method.Thirdly,the grid sensitivity of steel frame beam-column dog-bone connection nodes under different explosion proportional distances is studied and analyzed.Fourthly,it is explored to study the influence of different sizes of dog-bone connection between steel frame beam and column at the weakened part of steel beam flange on its anti-explosion performance.The main research results are as follows:(1)By designing orthogonal test with explosion distance,explosive mass and connection mode as three factors,the steel frame beam-column connection joint is simulated nine times.The influence of different connection modes on anti-explosion performance is analyzed by using range method.The analysis shows that the explosion distance has a greater influence on the anti-explosion performance of the joint.With the increase of the explosion distance,the influence of the explosion load on the joint decreases gradually.The influence of explosive mass on the anti-explosion performance of joint is less than the explosion distance.The impact of explosion load on joint increases gradually with the increase of explosive mass.The anti-explosion performance of steel frame beam-column connections with different connection modes is different.Dog-bone connections have better energy dissipation capacity and ductility.The end-plate bolted connections have better toughness and deformation resistance.(2)Influence of grid size on numerical simulation results of dog-bone connection between steel frame beams and columns.When the explosion scale distance is different,the influence of grid size on numerical simulation results is different.With the increase of explosion scale distance,the numerical simulation results are affected by grid size.In the finite element analysis of structures,the selection of grid size is an essential part of the numerical simulation process.It is necessary to consider the size of the structural model and the explosion proportional distance,and select the appropriate grid size to get more accurate numerical simulation results and save time and improve the operation efficiency.(3)The dimensions of the weakened position of steel frame beam-column dog-bone connection within the standard design range recommended by SAC include the distance from weakened point to column flange,weakened depth and weakened width.By taking these three dimensions as influencing factors and taking three horizontal values,the orthogonal test of numerical simulation of dog-bone connection node is carried out.The results of range analysis show that the distance from weakened point to column flange,weakened depth and weakened width have decreasing influence on the anti-explosion performance of steel frame beam-column dog-bone connection.In addition,the three factors are within the standard design range,and have little influence on the anti-explosion performance of steel frame beam-column dog-bone connection. |
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