Finite-element analysis of thermal fatigue of gas turbine blades. Part 2. Results of computations

Abstract

The results of the thermocyclic durability analysis  of samples for thermal fatigue tests and blades of gas  turbines are obtained based on the use of the deformation  criterion. In order to assess the accuracy of the thermal  fatigue characteristics of the material an estimation  of the inhomogeneity of the temperature fields,  plastic deformations and stresses in the working  part of samples of various types was made by means of direct finite element modeling. The influence of the hardening and the fixing temperature of the sample on the width of the plastic hysteresis loop was studied. It is shown that holding at the maximal temperature of the cycle substantially reduces the number of cycles before the macrocrack initiation. The computation method for evaluation of the thermal fatigue strength of gas turbine blades from poly- and single-crystal superalloys is proposed.