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Analysis of Turbine Disc for Creep Life

Abhishek S Makunte and Ramesh B N
Department of Mechanical Engg., AIT, Chikmagalur

Abstract—The deformation and fracture of gas turbine parts like turbine blades which are subjected to high temperature and other mechanical loads, depends mainly on temperature and time and hence due to creep. For reliable operation of a gas turbine, life prediction of the components of the turbine is of prime importance so that the damages can be detected and repaired before it gets problematic. In the present study, a low-pressure turbine disc is analyzed for the stress field under mechanical and thermal loading. The mechanical thermal loads and boundary conditions are imposed in the finite element analysis software ANSYS. A time hardening model is used to predict the stress relaxation and creep strain accumulations in the component with respect to time. The Larson-Miller Parameter (LMP) data is used to evaluate the constants used in this creep analysis. By defining the model through these constants, stress relaxation feature was captured and the total time in hours for an accumulated creep strain of 0.1% was calculated. The time required for the accumulation of the creep strain, without considering the stress relaxation phenomena was observed to be conservative by an order. Thus the considerations given to creep play a vital role in the design of machine components especially the aero gas turbine engine components, which are primarily subjected to severe mechanical and thermal loads.

Index Terms—Gas turbine, Creep life, Larson miller parameter, Stress relaxation

Cite: Abhishek S Makunte and Ramesh B N, "Analysis of Turbine Disc for Creep Life," International Journal of Mechanical Engineering and Robotics Research, Vol. 3, No. 3, pp. 792-801, July 2014.