【摘要】 针对航空发动机外部管路支架在整机试车中发生的断裂故障,经过断口分析,确定支架的断裂性质为疲劳断裂。从设计、加工、装配的角度进行故障树分析,确定裂纹萌生的主要原因是支架结构尺寸设计不合理,加上振动应力、装配应力及加工质量不符合要求综合所致。据此,提出两种支架改进方案,并通过建立有限元模型,分别进行了相同振动幅值和相同激振力下的强度对比分析。结果显示,通过增加支架厚度和宽度提高支架高周疲劳强度储备可以有效避免该故障的发生,且改进后的支架抗振能力大幅提高。经后续试验验证,支架断裂故障得以排除。更多还原

【Abstract】 Through fracture analysis against fracture failure of aero-engine external pipeline bracket which was found in test run, it was determined that the fracture property of the bracket was fatigue fracture. From the point of design, processing and assembly, the main reasons of the crack initiation were defined as unreasonable design of bracket structure, engine vibration stress, assembly stress and unqualified process through fault tree analysis. Two optimization schemes of bracket were presented. By establishing the finite element model, the strength analysis and comparison of the same vibration amplitude and exciting force were carried out respectively. The results show that the failure can be effectively avoided by increasing the high-cycle fatigue reserve through adding the thickness and width of the bracket. The anti-vibration ability of the optimized bracket is greatly improved. Follow-up test verifies that the optimized bracket fracture occurs no longer.更多还原