A STATISTICAL CUMULATIVE DAMAGE MODEL TO PREDICT THE FATIGUE LIFE OF HETEROGENEOUS MATERIALS UNDER CYCLIC LOADING

摘要

A statistical cumulative fatigue damage model is proposed in the present study to predict the fatigue life of the heterogeneous materials under cyclic loading. The microstructure of the heterogeneous materials is modeled as an ensemble of material microelements. The fatigue and fracture behavior of the microelement is described using a kinetic model for exhaustion of ductility. Fatigue failure occurs when the residual ductility of the microelements becomes equal to the applied cyclic strain amplitude. The statistical equation of residual ductility evolution is established and the density distribution function of the residual ductility is derived from the static ductility distribution. The fatigue life formula of the heterogeneous materials has been established.