Behavior of butt-welds and treatments using low-carbon steel under cyclic inelastic strains

The materials and details used to construct sacrificial structural steel components must be evaluated for the full range of inelastic demands imposed by extreme loading events. This study characterizes the cyclic response and low-cycle fatigue life of a plate steel material designed to have a relatively low yield stress and various complete joint penetration butt-weld details considered for use in applications where inelastic behavior is expected. Large amplitude cyclic strain tests were performed on the base material and butt-welded specimens. The welded specimens utilized several different weld treatment details designed to mitigate stress concentrations, reduce tensile residual stresses, and improve weld-toe geometry. Uniaxial material models and a low-cycle fatigue model were used to characterize the cyclic stress–strain response and low-cycle fatigue life of the specimens. A linear damage accumulation model was also applied and found to adequately predict the failure of specimens subjected to more arbitrary strain histories. The presence of butt-welds were found to only slightly decrease the low-cycle fatigue life and the various weld treatments were found to have minimal impact.

► Perform large amplitude cyclic tests on base-material and butt-welded specimens.
► Uniaxial material models fit to cyclic stress–strain data to characterize behavior.
► Low-cycle fatigue life parameters computed for each specimen type.
► Damage accumulation model applied to predict behavior under arbitrary loading.