航空发动机限寿件表面特征概率损伤容限评估

In order to meet the safety requirements of airworthiness regulations (FAR/CCAR33. 70) on life limited parts (LLPs), a probabilistic surface damage tolerance method was summarized based on the special material data, linear elastic fracture mechanics analysis and damage risk analysis. The damage tolerance assessment for hole features was analyzed and a new modified method for evaluating the probability of failure (POF) was proposed with higher efficiency. This method was verified referring to the test case provided by AC33. 70-2. The assessment result showed that the POF of the disk with hole features was 2.677×10^-4 times (20000 cycles) without any in-service inspection and 1.514×10^-4 times (20000 cycles) with two inspections at 4000 and 8000 cycles based on the assumption that 90% of the parts are inspected at 4000 cycles and an independent 90% of the parts are inspected at 8000 cycles. Based on the modified method, the conservative POF was 3.406×10^-4, demonstrating the preliminary compliance of airworthiness regulations. The surface analysis of damage tolerance assessment provides a support for evaluating the safety of hole features, which is instructive to other surface features.