Influence of transverse residual stress and welding defect on fracture performance of thick weld based on GTN damage model
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Welding residual stress (WRS) seriously affects the fracture performance of welded structures made of highstrength steel (HSS). Nevertheless, the influence mechanism of WRS on fracture performance remains unclear. In this study, a thick weld of Q690 HSS is fabricated, and experiments are conducted to test the tensile performance of the base metal (BM), welded metal (WM), and the welded joint. The Gurson-Tvergaard-Needleman (GTN) parameters for the thick weld are identified through experimental data and numerical simulation. Using transverse residual stress (TRS) and welding defects as initial inputs, the ductile fracture behavior of the thick weld is predicted through the identified GTN damage model. When TRS and welding defects are taken into account, the crack distribution shifts from the BM to the main WM and the back HAZ. The higher tensile stress in the WM, combined with welding defects, significantly reduce the fracture strength by accelerating the void growth and coalescence process.
Abstract
Welding residual stress (WRS) seriously affects the fracture performance of welded structures made of highstrength steel (HSS). Nevertheless, the influence mechanism of WRS on fracture performance remains unclear. In this study, a thick weld of Q690 HSS is fabricated, and experiments are conducted to test the tensile performance of the base metal (BM), welded metal (WM), and the welded joint. The Gurson-Tvergaard-Needleman (GTN) parameters for the thick weld are identified through experimental data and numerical simulation. Using transverse residual stress (TRS) and welding defects as initial inputs, the ductile fracture behavior of the thick weld is predicted through the identified GTN damage model. When TRS and welding defects are taken into account, the crack distribution shifts from the BM to the main WM and the back HAZ. The higher tensile stress in the WM, combined with welding defects, significantly reduce the fracture strength by accelerating the void growth and coalescence process.