Residual Plastic Strain Effects on the Ultimate Capacity for a HSLA Stiffened Panel Subjected to Two Different Cyclic Load Conditions

This paper delves into how plastic deformations accumulate in structures and their effect on the ultimate load strength. More precisely, the study examines how repeated cyclic loads cause plastic deformations, which could have some effects on the ultimate capacity of the structure, in contrast to a continuously rising load. The study suggests a numerical strategy, by means of finite element analyses, to investigate the structural responses of two different load cycle histories and emphasizes differences that arise due to the choice in the material hardening law (model describing material behaviour) like isotropic, kinematic, or the combined Chaboche model. The researchers focus on a stiffened panel made of high-strength, low-alloy steel subjected to both uniaxial compression and alternating tension-compression cyclic loading. In order to capture the arise of the residual plastic strains, the study employs shell element modelling, while also considering initial imperfections. The paper discusses how residual displacements magnitude change as the number of load cycles increases under different loading conditions and material hardening models. Ultimately, it analyses how these accumulated plastic deformations influence the ultimate strength, with a particular emphasis on whether different plastic strain inputs from the two load configurations lead to varying outcomes.