Effects of pre-tension and fatigue loadings on the evolution of welding residual stresses in welded plates

Abstract

Welding-induced residual stresses evolve under external loading and fatigue actions. This paper examines the effects of a variety of influencing factors on the residual stress evolution, such as the pre-tension, load ratio, variable amplitude loading, overloading, plate thickness, and crack depth, for which a comprehensive understanding is yet to be nurtured. The experimental and numerical findings demonstrate that the variable amplitude loading and overloading impose significant effects on the evolution of residual stresses during the cyclic loading test. Based on the experimental observations and numerical analysis, this paper presents four evolution forms of residual stresses and reveals their mechanical principles by the effective stress-strain curves in both the undamaged specimens and the fatigue-cracked specimens. The interaction between the positions with different incremental plastic strains changes the magnitude of residual stress and thus dominates the residual stress evolutions.