| The turbine disk is a core component of Aero-engine, and it's life determines the life span of the whole. Hence assessing the life of an aero-engine turbine disk has a significant science value. At present a myriads of experiments have shown that its main failure mode is low-cycle fatigue and the main method of low-cycle fatigue life is certainty analysis through the Manson-coffin formula which was amended by a variety of methods. However, the geometry and material parameters of the turbine disk unavoidly contains uncertainty because of the error in manufacturing, installation and other processes. Therefore the life of turbine disk also exists uncertainty and then the low-cycle fatigue life assessment in certainty will not be able to meet the needs of practical engineering.In this paper, after summing up the fatigue life assessment of turbine disk material,the Manson-coffin formula which was amended by the average stress was randomized. Considering the structural size tolerance of the turbine disk, some critical size was randomized in a certain way, and then the relative fatigue life model set up. In term of the reliability sensitivity analysis, the impact of size on the life was gained in quota. Then some suggestions on improvement of the structure of turbine disk were stated. The paper mainly including of following three aspects:(1) Based on parametric modeling software established the parametric modeling of the turbine disk. Through the parametric modeling, it is easier to change the structure and regeneration. Moreover it also lay the foundation for improving the structure.(2) Established the finite element simulation model for the Turbine disk both two-dimension and three-dimension. The stress distribution and possible failure areas were gained through the linear elastic analysis. And the further study showed the maximum stress in the region has entered the plastic deformation. Then the plastic strain distribution was got by the elastic-plastic analysis which lay the foundation for reliability of the fatigue life.(3) Based on aero-engine turbine disk material fatigue properties, established the reliability of fatigue life model. response surface method was applied to the fatigue reliability sensitivity analysis of the turbine disk and the advanced first order and second moment method (checking point method)was used to calculate the fatigue life reliability and reliability sensitivity.(4) According to the results of sensitivity analysis, identified the greatest impact factor for the reliability of fatigue, and then analyzed the reasons of these factors, and offered the structure improvements of the turbine disk. |
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