可靠性设计中材料屈服极限的最佳选择

OPTIMIZATION OF MATERIALS YIELD LIMIT FOR RELIABILITY DESIGN

根据航空发动机结构完整性大纲，对于断裂关键件必须进行损伤容限设计分析。由于材料缺陷，加工缺陷或疲劳引起裂纹的扩展，都会导致构件断裂，为此要求在有缺陷（裂纹）的情况下，构件应能保持足够的损伤容限，这主要靠正确选用材料，控制应力水平，采用抗断裂结构，控制加工精度及采用可靠的检查方法来实现。

According to aeroengine structure integrity program,fracture critical components must be analysed with damage tolerance concept.Due to crack propagation produced by material defects,working defects or fatigue defects can make structure fracture.Therefore,the sufficient damage tolerance should be maintained.It is realized by selecting material correctly,controlling stress level,using the anti fracture structures and reliable inspection.In this paper,the structural reliability concept is applied to studying optimization of materials for maximum reliability under certain stress levels and crack sizes,to investigating variation influences of material strength and stress level on structure reliability.