某机平尾大轴断裂损伤容限评定分析

Damage Tolerance Evaluation for Fracture of the Horizontal Tail Torque Tube for an Aircraft

根据某机平尾大轴在做疲劳试验时突然发生完全断裂,究其原因进行了损伤容限评定分析,并得出了分析结论:由于管壁腐蚀穿透裂纹已大于疲劳载荷谱工作应力所对应的临界裂纹长度,因此裂纹产生了不稳定扩展,换句话说,也就是疲劳载荷谱工作应力已大于腐蚀裂纹长度所对应的剩余强度要求值,因此导致了该大轴突然发生快速断裂。

Based on the case that full fracture of a horizontal tail torque tube for an aircraft occurred suddenly in a fatigue test, a damage tolerance evaluation was carried out for the fracture of the torque tube. The evaluation results indicate that because the full-thickness corrosion crack on the tube wall was longer than the critical crack corresponding to the working stress from fatigue load spectrum, the unstable crack propagation was caused. In other words, the working stress from fatigue load spectrum was greater than the residual strength corresponding to the length of corrosion crack. As a result, the shaft fractured suddenly.