Research on fracture of steel structure welded joint based on micro-mechanism. (September 2022) - Qu, Xiushu
Abstract: Fracture failure of welding joints is one of the primary forms in steel structure, and fracture prediction can provide suggestions and guidance for engineering applications. To predict the ductile fracture of welded joints, the Void Growth Model (VGM) and the Stress Modified Critical Strain Model (SMCS) based on the microscopic mechanism were studied. The tensile tests of Q355 steel, Q235 steel, ER50-3 and ER49-1 consumables commonly used in engineering were carried out. The constitutive models of four materials were established through the tensile tests of standard round bar specimens. The fracture parameters η mon and γ of base metal, weld metal, and heat affected zone were calculated through the tensile tests of notched round bar specimens and the UVARM (User subroutine to generate element output). Finally, the fracture prediction model was used to predict the fracture of the thin-walled steel tube beam-column joints, and the applicability of the VGM and SMCS models was discussed. The function f θ ¯ on the Lode Angle parameter is introduced to modify the VGM model. The modified fracture prediction model was used to predict the initial fracture of beam-column joints.