PREDICTION OF CRACK INITIATION LIVES OF NOTCHED SPECIMENS UNDER BIAXIAL LOADING

摘要

A dominant fraction of total fatigue life may be spent in crack initiation and small crack growth. The aim of this research is to predict crack initiation lives of engineering components under multiaxial loading conditions. Both numerical analysis and experimental methods are applied for a notched specimen. FE analyses were carried out for the notched shaft under combined bending and torsion loadings using ABAQUS finite element code. Kinematic hardening model with von Mises yield criterion and associative flow rule was used for elastic-plastic FEA. The approximate methods, the Neuber's rule and Glinka's rule, are also used to estimate the equivalent stress-strain behavior as a comparison. Recent multiaxial fatigue models are reviewed, and the critical plane damage models are applied for life predictions in this paper. The predicted and experimental results of the crack initiation lives of notched specimens are compared. Their prediction accuracy and the computational aspects are discussed in this paper.