Life estimation of turbine blisk for a gas turbine engine

The present paper deals with fatigue analysis of a turbine blisk (integrated blade and disc) for a small gas turbine engine for a short life application. Due to high rotational speeds, the blisk is subjected to high centrifugal loads. This blisk experiences varying stress amplitudes due to mission profile of the vehicle, which includes cruise and maximum thrust. Studies show that the low cycle fatigue is the critical failure mechanism of turbine blisk, hence strain-life approach is followed. A nonlinear elastic-plastic finite element analysis is carried out in ANSYS Mechanical and the strain amplitudes are obtained. The results from static structural analysis are fed to ANSYS nCode Design Life tool for further fatigue life estimation. The damage accumulation is obtained using Palmgren-Miner’s rule and Smith-Watson-Topper’s mean stress correction method is used to obtain the strain-life curve