Mechanical behaviors and constitutive model of structural steel influenced by strain aging: Fid-Bau Portal

Mechanical behaviors and constitutive model of structural steel influenced by strain aging

Yang, Yiting / Zhang, Baojun / Wang, Yan / Jiang, Zhipeng / Li, Kehao

Abstract The effects of static strain aging on Q355B and Q460C low-alloy structural steel specimens were investigated to determine the differences and similarities of the strain aging effects, and to obtain more test data on strain aging effects on structural steel materials. The specimens made of the two low-alloy structural steel materials were pre-strained up to different strain limits and then kept at room temperature for different aging times, up to one year. At selected aging times, the specimens were reloaded until failure. The stress–strain response and mechanical parameters of both steels changed significantly. The pre-strain had a greater effect than the aging time. A possible correlation was inferred between the macro-mechanical properties and changes in the microstructure of the low-alloy structural steel. The parameters of the multi-linear and nonlinear constitutive models of low-alloy structural steel influenced by static strain aging were updated according to the test data. Additionally, a revised multi-linear constitutive model was established, which presents the nonlinear material property of the steel influenced by strain aging and makes the numerical simulation more efficient. Based on the test data, the constitutive models can describe the stress–strain relationship of low-alloy structural steel under monotonic loading with different levels of strain aging.

Highlights • The effect of static strain aging on the mechanical behaviors of low-alloy structural steel specimens is investigated. • An increase in yield stress and a decrease in elongation after fracture are the universal indications of strain aging. • The pre-strain has a larger effect on the mechanical behaviors of low-alloy structural steel than the aging time. • The stress-strain curves show that the yield phenomena of low-alloy structural steel change with strain aging effects. • The constitutive model of the two low-alloy structural steels influenced by static strain aging were established.