A Continuum Damage Mechanics Approach for Fatigue Life Prediction of Open-Hole Metallic Plate

Abstract

A damage evolution model is presented for fatigue life prediction of metallic structures. This model is formulated based on damage mechanics and the irreversible thermodynamics framework developed by LEMAITRE and CHABOCHE. Using this model, the fatigue lifetime can be predicted both in the high cycle fatigue (HCF) regime and the low cycle fatigue (LCF) regime. Based on the energy theory and material fatigue test data, the plastic strain threshold for damage initiation was modified for HCF and LCF respectively. The damage evolution parameters were determined according to the fatigue test results of standard specimens. A damage mechanics-finite element full-couple method was adopted to simulate the process of fatigue damage evolution. The numerical simulation of fatigue lives were compared with the fatigue tests of 2A12-T4 open-hole plates and good agreement was obtained.