Lifetime Assessment of Steam Turbine Casing

Nowadays, in order to accommodate electrical grids that include fluctuating supplies of green energy, more and more fossil power plants are increasingly required to start up and shut down frequently. The increased number of stress cycles leads to a significant reduction of lifetime. In this paper, numerous load cycles of steam turbine casing including various start up and shut down conditions were numerically investigated by using the finite element analysis(FEA). The total strain throughout the cycles was directly calculated by the elastic-plastic material model. The delta equivalent total strain was determined by rainflow count method, and the assessment of lifetime was evaluated.