寿命限制件概率失效风险评估材料缺陷数据模型

In order to meet the airworthiness requirements, a method for obtaining material defect (hard α inclusions) distribution data of typical titanium alloy was explored. According to the theoretical model of titanium alloy disk manufacturing process, the defect distribution baseline was acquired, using the detected defect distribution and the probability of detection(POD) of nondestructive test in the manufacturing process. The programs of POD test and microsection test, which meet the airworthiness requirements, were proposed. The key test technologies were determined to obtain POD curve and detected defects data, including specimen specifications, nitrogen mass fraction and distribution of hard alpha inclusions, ultrasonic test standard, steps of microsection, etc. Then, the exceedance curve of defect distribution was acquired by the use of theoretical deduction and logarithm linear fitting. The characteristics of material defects and airworthiness requirment were determines, then a method of obtaining POD curve and defect distribution curve was put forword.The method provides inputs for probabilistic risk assessment on aero-engine disk, supporting the airworthiness forensics of aero-engine disk.