基于缺陷分布形式的粉末冶金涡轮盘可靠度计算模型

Model for Calculating the Reliability of Powder Metallurgy Turbine Disk Based on Distribution of Defects

为研究微缺陷对粉末冶金涡轮盘可靠性的影响,在有限元分析结果的基础上,基于国内粉末盘中缺陷分布的概率特点,建立针对低循环疲劳裂纹萌生和裂纹扩展失效模式的可靠度计算模型。该模型可计算不同缺陷分布形式、不同循环载荷条件下的轮盘可靠度。对某型粉末盘失效概率的分析表明:表面质量是导致粉末盘失效的重要因素,这同大量试验研究结果相一致,对粉末盘的设计和使用具有工程指导意义。

In order to research the effect of micro defects on the performance of powder metallurgy （PM） turbine disk, a reliability calculation model based on the probabilistic character of distribution of defects is established by using the results of finite element analysis, which is aimed at the failure mode of crack initiation and propagation under low cycle fatigue. The model can be used to calculate the reliability of PM turbine disk under different distribution of defects and different cyclic loading conditions. Then failure analysis ofa PM turbine disk indicates that the surface quality is an important factor leading to failure of PM turbine disk, and that is in good agreement with a great deal of experimental results. So the model can be used to guide the engineering design and application of PM turbine disk.