Experimental Study to Calibrate Cyclic Micromechanics-Based Fracture Models of Q345 Steel

Earthquake-induced cyclic loading usually involves less than ten cycles and strains that are in well excess of yield. Such conditions are defined as ultra low cycle fatigue (ULCF). Micromechanics- based facture models have been verified to accurately predict ductile fracture in steel structures under ULCF commonly seen in earthquakes. The degraded significant plastic strain (DSPS) model and the cyclic void growth model (CVGM) are fit for fracture prediction under ULCF loading. In order to extend the use of these cyclic micromechanical models to predict ductile fracture in welded steel connections in China, this paper conducted material tests and finite element analyses to calibrate the parameters in these models for popularly used Q345 steel. The results of this paper can be applied to predict ductile fracture in welded steel connections under ULCF loading.