Experimental and numerical investigation on ultimate strength of laser-welded stiffened plates considering welding deformation and residual stresses

Abstract The ultimate strength of laser-welded Al–Li alloy stiffened plates is experimentally and numerically analyzed in this study. The ultimate strength, failure mode, and strain evolution process of stiffened plates were measured through tension experiments combined with digital image correlation (DIC) and electrical measurements. Then, based on the established finite element model (FEM) considering material nonlinearity, geometry nonlinearity and ductile damage, the ultimate strength and failure mode of stiffened plates were simulated; and the influence of welding deformation and residual stress was investigated. The weld morphology, measured by metallographic experiment, validated the thermal–elastic–plastic model for predicting welding deformation and residual stresses. The results showed that the FEM considering welding deformation and residual stresses can accurately predict the failure modes and ultimate strength of stiffened plates.