Stress Analysis and Life Estimation of Gas Turbine Blisk for Different Materials of a Jet Engine

The gas turbine is the heart of all modern aircraft. The role of the turbine blisk in a gas turbine is to expand the hot gases which come out from the combustion chamber and to provide the necessary thrust required, for the propulsion of the aircraft. Therefore the turbine blisk is the most critical part in a gas turbine engine. It also develops the power required to drive the compressor and other accessories. Three materials namely NI 90, MAR M 247 and IN 718 are being currently used for the manufacture of gas turbine blisk. These are nickel based super alloys. It is necessary to determine which among the three materials exhibit better fatigue life characteristics. In the present work a sector of the blisk (Bladed Disc) has been modeled using ANSYS 11.0 Finite Element Analysis software. The three different materials mentioned above are being considered for analysis, in the present study. Stress analysis has been carried out by the application of the boundary conditions and loads. The results obtained from the analysis have been used to determine the fatigue life and factor of safety by using relevant formulae. It is observed from the analysis that IN 718 has been found to exhibit better fatigue life characteristics.