Applying weld toe process design in finite element analysis of super large structure

Abstract

Structural analysis does not consider weld seam. Research on welding seldom pays attention to structural strength analysis. The working conditions of super large structure are complex, and the design requirements are very high. The coupled relationship between the structure of weld toe and frame stiffness in actual working conditions is analyzed to improve the accuracy of finite element model. Using the finite element method as basis, this study establishes the finite element model for the frame. The fillet joint models for the different forms of weld toe are established on the basis of thermo-elastic/plastic theory. Weld toe optimization scheme is applied to analyze frame strength. The accuracy of the model is verified by experiments. Results show that high stress appears at the connection position of the left-right longitudinal beam and rear torsion tube and the middle of rear torsion tube due to the interaction of torsion and braking. Stress between the frontal longitudinal beam and portal-type girder assembly does not significantly vary. The weld height and toe of the fillet joint are 20 mm, and the stress peak value is small. The stress distribution of the frame is analyzed by optimizing the weld toe. The stress peak value is reduced from 453.8 MPa to 340.6 MPa. Through the repair welding of the weld toe position for the optimization scheme, the welding seam surface forms a concave arc and reduces the stress concentration effectively. Failure time of the frame increases by no more than 5000 hours and does not exhibit fatigue failure. Research results are crucial for establishing coupled relationship with weld toe and frame strength and optimizing welding.