Thermal-Mechanical Life Prediction System for Coated Anisotropic Turbine Components Available to Purchase

Modern gas turbine engines provide large amounts of thrust and experience severe cyclic thermal gradients with sustained mechanical loads. Fatigue damage induced by cyclic thermal transients, along with creep and oxidation damage caused by quasi steady state, long hold-time periods, have emerged as critical life-limiting factors for coated turbine airfoils. It is, therefore, necessary to develop key thermal parameters for life prediction system for hot section components that accounts for operating thermal transients of anisotropic material properties for coated airfoils. Thermal cyclic deformations are determined as a function of the cyclic temperatures and sustained mechanical loads. This leads to the evaluation of local cyclic fatigue damage function, which can be compared against the strain energy density dissipated during monotonic deformation testing for damage assessment. Long hold-time periods at elevated temperatures also lead to cumulative effects of creep and oxidation. Key thermal-mechanical parameters, obtained from the formulation presented, arise as governing parameters, leading to analytical maps necessary to track the damage observed in cyclic thermomechanical test specimens. The contributing damage modes of thermal fatigue, creep and oxidation are summed by the traditional Miner’s rule of accumulated damage. This provides a way to determine the number of cycles remaining in the part.