焊接方钢管节点抗火性能分析word格式论文.docx

优秀毕业论文 精品参考文献资料 ABSTRACT For square tubular joint with hollow section, local buckling failure usually occurs around the chord/brace intersection on chord surface due to inadequate radial stiffness of chord which is generally lower than the axial stiffness of brace when axial load is applied on the brace end of tubular joint. Additionally, that yield strength and elastic modulus of steel degrade considerably at elevated temperature makes unprotected tubular joints with hollow section destroyed easily in the condition of fire. Hence, it is necessary to study the fire resistance of square tubular joint so that some recommendations could be provided for engineering design and norm. In this thesis, the fire resistant performances of two square tubular T-joints with hollow section are tested. During tests, a constant axial load is applied at brace end firstly, and then the T-joint is heated in accordance with standard heating curve until failure of the joint. The temperatures on tube surface and displacements of joint are monitored during test, and the heating process, failure mode and failure procedure of T-joint under fire are also recorded. Then, general finite element software ABAQUS is used to simulate the fire resistant experiments of the T-joints. By comparing the results of finite element simulation and tests, the accuracy and reliability of temperature model and force/displacement model is proved. The results of experiments and finite element analysis show that the whole failure procedure of square tubular T-joint with hollow section under fire could be divided into three stages comprised of expanding and deformation decreasing of joint at the beginning of heating, deformation increasing caused by deteriorated mechanical properties of steel with the temperature increasing and failure stage in the end. (2) The failure mode of square tubular joint with hollow section at elevated temperature, which is similar with the one at ambient temperature, is local buckling a