METHOD FOR PREDICTING FATIGUE LIFE OF GEOMETRICALLY DISCONTINUOUS STRUCTURE

摘要

A method for predicting the fatigue life of a geometrically discontinuous structure, comprising the steps of: establishing a geometrically continuous first finite element model, defining a crystal plasticity constitutive equation, thereby obtaining a stress-strain relationship of a material under a given cyclic loading condition (S1); carrying out a uniaxial tensile test and a uniaxial fatigue test to obtain a tensile curve and a hysteresis loop (S2); obtaining the tensile curve and hysteresis loop by means of test parameter fitting, and acquiring material parameters and a critical value of fatigue plastic slip required by the crystal plasticity constitutive equation (S3); establishing a second finite element model of the geometrically discontinuous structure, and acquiring a stress-strain relationship of each cycle and a single-cycle fatigue plastic slip value (S4); and calculating the crack initiation life of a notched specimen (S5). The method for predicting the fatigue life of the geometrically discontinuous structure may better achieve the fatigue analysis of the geometrically discontinuous structure at different temperatures, and may also accurately predict the location of crack initiation. The method has the advantages of intuitiveness, strong applicability and high accuracy.