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

Investigation of creep behavior of a gas turbine blade with a Visco plastic FEM 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 approximate approaches such as Larson Miller Parameter method. These methods are not accurate enough and have several restrictions. Therefore, in this paper, finite element (FE) models based on time-dependent plastic behaviors are investigated for simulation of creep phenomenon in turbine blades. Three different time-dependent plastic models are employed to estimate the lifetime for a turbine blade. The material of the blade is considered to be cast Ni-base super alloy known as Inconel 738LC. The results are compared with the available experimental data and also the results obtained by the Larson Miller Parameter method. It is shown that, the proposed models gives more realistic results and the predicted lifetime is almost longer than that obtained using elastic stress analysis and Larson Miller Parameters method.