Elastic-Plastic Finite Element Simulation and Fatigue Life Prediction for Beam and Elbow Under Cyclic Loading

Abstract

Work hardening and Bauschinger effects on plastic deformation and fatigue life for a beam and an elbow under cyclic loading are examined using finite element analysis (FEA). Three typical material plastic hardening models, i.e. isotropic, kinematic and combined isotropic/kinematic hardening models are adopted in the FEA calculations. Based on the FEA results of cyclic stress and strain at a critical location and using an energy-based fatigue damage parameter, the fatigue lives are predicted for the beam and elbow. The results show that (1) the three material hardening models determine similar stress at the critical location with small differences during the cyclic loading, (2) the isotropic model underestimates the cyclic plastic strain and overestimates the fatigue life, (3) the kinematic model overestimates the cyclic plastic strain and underestimates the fatigue life, and (4) the combined model predicts the intermediate cyclic plastic strain and reasonable fatigue life.