Simulation of ductile fracture initiation in steels using a stress triaxiality–shear stress coupled model
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Micromechanics-based models provide powerful tools to predict initiation of ductile fracture in steels. A new criterion is presented herein to study the process of ductile fracture when the effects of both stress triaxiality and shear stress on void growth and coalescence are considered. Finite-element analyses of two different kinds of steel, viz. ASTM A992 and AISI 1045, were carried out to monitor the history of stress and strain states and study the methodology for determining fracture initiation. Both the new model and void growth model (VGM) were calibrated for both kinds of steel and their accuracy for predicting fracture initiation evaluated. The results indicated that both models offer good accuracy for predicting fracture of A992 steel. However, use of the VGM leads to a significant deviation for 1045 steel, while the new model presents good performance for predicting fracture over a wide range of stress triaxiality while capturing the effect of shear stress on fracture initiation.
KeywordsDuctile fracture Void growth Stress triaxiality Shear stress ratio ASTM A992 steel AISI 1045 steel
Y.Z. Zhu and M.D. Engelhardt thank the funding support of the National Science Foundation (Grant 1344592). Z.F. Pan gratefully acknowledges the support of the National Natural Science Foundation of China (Grant 51778462) and the National Key Research and Development Plan (Grants 2017YFC1500700 and 2016YFC0701400).
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