Calibrating an adaptive cohesive zone model to simulate ductile crack propagation in structural steel under cyclic loading

A procedure is outlined for calibrating a finite element model to simulate ductile cracking that employs a continuum damage criterion for ductile fracture initiation, termed the Stress Weighted Ductile Fracture Model, with an Adaptive Cohesive Zone method to simulate crack propagation. The proposed procedure is implemented and validated with data from 44 coupon-scale tests of an A913 structural steel. The fracture model calibration is performed in two stages to determine parameters to evaluate: (1) the continuum damage mechanics criterion and (2) ductile crack initiation and propagation. Sensitivity of the calibration to parameter uncertainty is evaluated using synthetic data, followed by calibration and validation against experimental test data. The results indicate that the computational model can accurately simulate the overall response of experimental specimens, as well as other key aspects of observed behavior, including crack tunneling and crack face closure. Guidelines are provided for practical calibration of the model components.