Research On Dynamic Behavior Of Axially Pre-loaded Cold-formed Square Steel Tubular T-joints Under Impact Load

With the rapid development of social economy, more and more steel tubular structure buildings are used in our daily life. Due to the impact, explosion, earthquake and other disasters, structure severely damaged even collapse accident to happen from time to time, the shock resistance of steel tubular structures cause the attention of many scholars. Steel structure building in the use of the process, due to the existence of the structure and design of the bearing weight load, the chord tube of tubular structure will bear a certain amount of axial force. Tubular joint is a key part of the steel tubular structure. Its shock resistance has very important influence on the overall impact resistant ability of tubular structure. If tubular joint under lateral impact load, the destruction of the joint location can cause the decline of structural stiffness, bearing capacity and stable performance, which results in the serious consequences of the overall structural failure and even the collapse. Therefore, the research on resistant performance of tubular joint under impact loading has great engineering significance. The mechanical property of axially pre-loaded tubular T-joint under lateral impact loading is studied in this text. The research work can be summarized as follows:(1) The drop hammer impact test of steel tubular T-joint under axially pre-loaded was carried out. The axial compression ratio of the joints and width ratio of branch to chord tube were the main control variables. The failure modes, time history of deformation curves, time history of impact force curves and other data were recorded in the tests. And the resistant performances of joints under two variables have been studied.(2) The finite element model of axially pre-loaded tubular T-joint subjected to lateral impact was developed using ABAQUS, and the failure modes, time history of impact force curves, time history of deformation curves and other data which were acquired from the model and test were compared. Therefore, the rationality and accuracy of the finite element model was verified. It can provide the basis for the analysis of the mechanism of the later.(3) The resistant performance of tubular T-joint subjected to lateral impact was analyzed by investigating the local and global deformation, the dissipated energy and other data. The axially pre-loaded tubular T-joint under local reinforcement was discussed, and made an attempt.