Study on low-cycle hysteresis properties of seawater corroded steel considering loading history effects

To investigate the combined effects of wave loading history and time-dependent corrosion damage on the hysteresis mechanical properties of long-term serviced marine engineering materials, this study conducted hysteresis mechanical experiments and a generalized mechanical model research on corroded steel, considering the influence of high-cycle loading history. Steel corrosion was pre-generated by accelerated electrochemical corrosion method. Developing the early-stage high-cycle fatigue loading system and later-stage low-cycle hysteresis loading system based on the dynamic characteristics of wave loads, seismic actions, and typhoon-level pulsating wind loads. Analyze the influence of the independent and combined effects of early-stage load stress levels, cycle times, and corrosion damage on the steel capacity to withstand low-cycle high-stress hysteresis loading. Based on test results and mechanical properties, an improved generalized hysteresis mechanical model was established that encompassed monotonic tension curves, skeleton curves, and well-defined loading and unloading rules. The validity and universality of the model were verified through various loading systems and hysteretic tests of corroded steel. The results indicated that the early-stage high-cycle fatigue history led to a reduction in the material's elastic range, causing the material to transition into plasticity earlier. The combined effects of early-stage loading history and corrosion damage resulted in a significant degradation of the material's hysteresis mechanical properties.