The Choice of Static Recovery Term Description to Address the Effect of Hold Time Periods of Load Cycles on the Ratcheting of Steel Samples at Room Temperature

The present study evaluates three static recovery term (SRT) formulations incorporated into the Ahmadzadeh–Varvani (A-V) kinematic hardening framework for predicting ratcheting under tensile peak hold loading at room temperature. Linear, power-law, and nonlinear SRTs were assessed using experimental data for austenitic stainless steels SUS304 and SS304. The constitutive parameters were first calibrated using monotonic, strain-controlled, hysteresis loop, and no-hold ratcheting data. The SRT coefficients were then calibrated using peak hold experiments involving hold durations of 60 s for SUS304 and 10 s for SS304. All three formulations reproduced the increased hysteresis loop translation and ratcheting strain caused by the tensile holds more accurately than the baseline model without static recovery, which underpredicted ratcheting strain by an absolute strain difference up to 1.5%. The three SRTs produced comparable overall ratcheting predictions after calibration; however, they generated different coefficient evolutions, recovery histories, and intermediate cycle responses. The nonlinear formulation provided improved agreement for portions of the SUS304 loop evolution, while the linear model offered the simplest implementation. The results demonstrate that static recovery is essential for modelling dwell-assisted ratcheting and that model selection should consider internal variable evolution in addition to final accumulated strain.