Evaluation of Creep Damage in Some Major Components of Steam Turbine

Summary

The paper presents a finite element analysis of some physically non-linear problems of material creep in application for machine parts operating under creep conditions. The numerical solution is based on a statistically stable analytical relationship for plastic deformation which expresses all three stages of creep process. Por the variable load and/or temperature modelling at multiaxial state of stress the equivalence of local damage according to the hypothesis of linear cumulation of damage is used. The suggested method is suitable for creep calculations of geometrically complicated bodies with respect of local damage at the points of deformation and stress concentration. Physically real boundary conditions were included in the FEM numerical technique. Dispersion of the creep tests is accounted for and the numerical results are compared with measurements.