Failure and damage of steel thin-plate elements and angle members due to very-low-cycle loading

In this paper, an experimental investigation is carried out to determine the important factors in causing cracks and the rupture of steel members and their elements under large imposed and repeated deformations, and the quantitative relationships between the important physical factors leading to failure. Nine thin-plates and 28 angles served as specimens, and were subjected to repeated axial loading after undergoing inelastic buckling. Particular attention was paid to the effects of loading patterns, failure modes, and the cross-sectional shape of the very-low-cycle fatigue behavior under repetitious loading in the order of a few to 20 cycles. The experimental results show that energy dissipation capacity depends on the entire history of loading, the failure mode, the slenderness ratio, and the width-to-thickness ratio. No simple quantitative relations were observed between the initiation of the visible cracks or rupture and the energy dissipation capacity. The maximum values of residual “net” strains are found to range from 25% to 40%, independent of the test parameters.