| In the paper, The LCF experiments were done for axial loading constant-amplitude of the GH4133 metallic materials at 250 °C , turbine disks test temperature, with two strain-ratios R=-l & R=0.44. Two probabilistic formulae of cyclic Δσ - Δε and Δε - Nf were established based on the experiments data.The fatigue critical site aside turbine disk pin-hole was located based on the FEA of ANSYS. Model of the turbine disk was built using the Parameter Design Language (APDL) and the strain amplitude of fatigue critical site aside pin-hole was computed by the FEA, which should be effected by the dispersion of the material parameters, loading and interference between the pin and pin-hole. The strain amplitude aside the pin-hole was fit by the second order Response Surface. The cumulative distribution function of strain amplitude was achieved with Monte Carlo method. The probabilistic formulae of cyclic Δε - Nf were established based on symmetrical andunsymmetrical cyclic fatigue experiments data and the reliable LCF life of the turbine disk were obtained.The fatigue incidental bar specimen and imitation specimen of the critical site aside turbine disk pin-hole were designed. The influence of stress gradient was simulated by the test of imitation specimen and the life reliability of the specimen was analyzed. The fatigue life of the turbine disk was evaluated based on experiment results of the bar specimens and the imitation specimens.It was demonstrated that the numerical results of life fit well with the experimental ones. It is rare that in china the fatigue life of turbine disk was evaluated by the experiments of imitation specimen as far as I know. |
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