A cyclic plastic zone size-based defect tolerant design approach to predict the fatigue life of additively manufactured alloys

Abstract

The primary obstacles to utilizing additively manufactured metallic alloys in industry are their inadequate ductility and manufacturing imperfections. Defects in the alloys can result in stress concentration, which can further deteriorate their tensile ductility and fatigue performance. In this study, defect tolerant design methods based on physics are explored to forecast the fatigue performance of 17-4 PH stainless steel that has been additively manufactured. A cyclic plastic zone size-based finite element approach is proposed in this work to predict the fatigue performance of additively manufactured alloys. Initially, defects will be identified from the microstructure of the material, and a finite element model will be created from the microstructure; then, a kinematic hardening model will be used to determine the size of cyclic plastic zone around all defects. The largest size of cyclic plastic zone will cause failure and be identified as a killer defect, and the fatigue life will be calculated on the basis of that killer defect. The proposed method predicts the fatigue life of additively manufactured alloys well.