THERMO-MECHANICAL FATIGUE ANALYSIS OF A STEAM TURBINE SHAFT

Abstract

Increasing demands on the flexibility of steam turbines due to the use of renewable energy sources substantially alters the fatigue strength requirements of components of these devices. Rapid start-ups as well as the increased number of the load cycles applied to the turbines must be handled by design methodologies. The goal of the work presented in this paper was to provide a computational framework applicable to the thermo-mechanical fatigue (TMF) prediction of steam turbine shafts. The so-called Damage Operator Approach by Nagode et al. has been implemented to the software codes and applied to fatigue analysis of the thermo-mechanical material response computed numerically by the finite element analysis. Experimental program conducted in order to identify the material thermo-mechanical behavior and to verify numerical simulations is introduced in the paper. Some results of TMF prediction of a sample steam turbine shaft are shown.

Keywords

• fatigue prediction, thermo-mechanical fatigue, finite element analysis, Chaboche elasticplastic model