Effect of loading protocols on the hysteresis behaviour of hot-rolled structural steel with yield strength up to 420 MPa

This paper presents a series of material tests on hot-rolled structural steel with nominal yield strength ranging from 235 MPa to 420 MPa to study the effect of loading protocols, material thickness and yield strength on the hysteresis behaviour. A total of seven tensile coupon tests were conducted and a total of twenty one experiments were conducted in cyclic axial configuration on hot-rolled structural steel. Three different cyclic loading protocols were adopted namely, Cyclic Ascend, Cyclic Alternate and Cyclic Tensile with strain amplitudes varying between +/-0.5% to +/-2%. The results of the hysteretic responses at different loading protocols were presented and compared. The results revealed the non-masing and accumulated strain-hardening behaviour of the tested materials and the effect of material thickness and yield strength on the characteristics of hysteretic response was minimal. The loading protocols affect the hysteresis behaviour but are insignificant for seismic applications within the range of the strain in the tests