粉末冶金涡轮盘裂纹扩展可靠性分析方法

以粉末冶金夹杂裂纹扩展寿命预测理论为基础，建立了裂纹扩展可靠性分析的剩余强度干涉模型与寿命干涉模型。采用改进一次二阶矩法分析单个夹杂裂纹扩展的可靠性。为了分析多个夹杂裂纹扩展的可靠性，提出了随机裂纹位置的均值等可能分布的多裂纹分布模型，与随机裂纹位置的均值处在夹杂所占体积中心的多裂纹分布模型相比，本文模型更偏于安全，且适合于工程应用。所提方法被应用于计算某粉末冶金涡轮盘裂纹扩展的失效概率，分析结果表明夹杂位置距离表面较近的裂纹引起的失效概率大。

Reliability Analysis for the Crack Growth of Powder Metallurgy Turbine Disk

Based on life prediction of fatigue crack growth in a powder metallurgy, the residual strength interference model and life interference model are proposed to analyze the reliability of the fatigue crack growth. The reliability of the fatigue crack growth life of single inclusion is analyzed by the advanced first order and second moment method. In order to obtain the crack growth reliability of multiple inclusions existed in the structure, a new model, where the mean value of the random inclusion position is distributed uniformly, is presented. Comparing with the available model, where the mean value of the random inclusion position is at the center of the volume occupied by the corresponding inclusion, the new position distribution model is more safe and more suitable for engineering application. In the illustration, the above reliability method is applied to analyze the reliability of a powder metallurgy turbine disk. The results show that the position of the inclusion in the turbine disk has significant effect on the failure probability of the crack growth.