Investigation of creep behavior of a gas turbine blade with a Visco plasticFEM model to estimate the blade life

Creep is one of the most important factors in failure of turbine blades.Usually the life of a turbine blade is estimated based on approximateapproaches such as Larson Miller Parameter method. These methods are notaccurate enough and have several restrictions. Therefore, in this paper, finiteelement (FE) models based on time-dependent plastic behaviors areinvestigated for simulation of creep phenomenon in turbine blades. Threedifferent time-dependent plastic models are employed to estimate thelifetime for a turbine blade. The material of the blade is considered to becast Ni-base super alloy known as Inconel ۷۳۸LC. The results are comparedwith the available experimental data and also the results obtained by theLarson Miller Parameter method. It is shown that, the proposed modelsgives more realistic results and the predicted lifetime is almost ۵۰% longerthan that obtained using elastic stress analysis and Larson Miller Parametersmethod.

Keywords:

Visco plastic , FEM , Creep , Turbine Blade , Blade life time