Experimental and numerical study on residual stress distributions in welded H-sections of High-strength steel

High-strength steel (HSS) has been increasingly applied in structural engineering, while the work on residual stress of HSS sections is still insufficient. Limited research is available for welded H-sections above 690 MPa while with a plate thickness of more than 10 mm. This paper deals with the residual stress distributions of welded H-sections with flame-cut edges, which are fabricated from HSS plates with yield strength of 690 MPa and 960 MPa and thickness of 10 mm-20 mm, using both experimental and numerical method. The experiments showed that the welded tensile residual stresses in the weld region are not significantly affected by sectional dimensions and steel grade. Verified by comparing with the experimental results, three-dimensional (3D) finite element (FE) models using sequentially coupled thermal-stress analysis was adopted for parametric study of compressive residual stress of welded H-sections made of 690 MPa HSS. The results showed that the compressive tensile stress is negatively correlated with plate thickness as well as width-thickness ratio. Through regression analysis, formulae were proposed for estimation of compressive residual stress in the flange and web, respectively. Finally, residual stress distribution model was developed, which was proved effective by comparing with the experimental and FE results.