Finite element simulation of creep crack growth using combined plastic-creep damage model

Abstract

This paper compares a combined plastic and creep damage model with only creep damage model by simulating creep crack growth of P91. The previous model considered only creep damage is extended to consider effect of plastic damage to creep crack growth. The damage model is based on the stress-modified fracture strain model using the ductility exhaustion concept. Also, creep fracture strain depending on the strain rate is considered. Total damage is defined simply through linear addition of plastic and creep damage. When the accumulated damage becomes unity, all stress components at the finite element gauss point are reduced to a small value to simulate failure. Finite element damage analysis results using previous and proposed model are compared with experimental data for P91. The proposed model gives a better agreement with the experimental data compared with the previous model.