Comparison Between Strain-Based and Energy-Based Creep Failure Simulation

The power plant is required to operate under high temperature and pressure for high efficiency. In order to predict reliable life time of power plant under high temperature, creep-low cycle fatigue life prediction method should be proposed. In this paper, strain based and energy based failure model are proposed to simulate notch bar creep tensile test. Modification factors considering multiaxial fracture and strain rate effect were proposed in order to simulate notch bar creep tensile test using FE analysis. Using proposed models, FE result of strain based and energy based damage model are compared with notch bar creep tensile test. As a result, both strain and energy based damage model simulates crack growth well during creep, However, when tertiary creep behavior is considered, energy based failure model simulate rupture time longer than strain based model. It can be inferred that plastic damage accumulation of energy based model is slower than that of strain based model.