Continuum Damage Mechanics Application in Low Cycle Fatigue Damage Assessment for Steam Turbine

In this article, a nonlinear continuum damage mechanics(CDM) model is developed to assess the low cycle fatigue damage of a steam turbine rotor. Two simulation experiments are carried out to introduce theory of CDM. First one makes an effective validation of its serviceability in thermal engineering, and the second one calculates the low cycle fatigue damage on the rotor of a domestic 300 MW steam turbine unit. Based on the relation of the cyclic stress-strain, a conservative character of present continuum damage mechanics model is exhibited. The calculation results are compared with those of the linear accumulation model, thermal entropy model and practical test data. Comparison results indicates that present nonlinear CDM model is able to describe the damage accumulation of turbine rotor more precisely and reasonably in practical thermal engineering.