低压三级转子叶片销钉孔断裂分析

某机在大加力起飞过程中振动大,发动机声音异常,分解后发现一片低压三级转子叶片从销钉孔处断裂。对叶片销钉孔断口宏、微观特征进行分析,对加工质量、工艺、尺寸进行复查,并在叶片振动计算和测频试验结果分析的基础上,确定叶片的失效原因。分析结果表明:其失效原因是在叶片销钉孔进气边侧靠近端面处存在台阶,致使在工作状态下最大受力点处的应力升高,在该处形成了应力集中的疲劳源,最终导致叶片销钉孔发生疲劳断裂。

Failure Analysis for Pin Hole of Low-pressure the 3rd Stage Rotor Blade

The plane vibrated largely at afterburning process with aero-engine＇ s abnormal sound. A Low-pressure the 3rd stage rotor blade was found to have fractured from the pin hole. In order to find out the mode and cause of the failure, macro and micro observation were analyzed, machining quality, producing technology and dimension of parts were reexamined. In addition, vibration calculation and frequency measure were carried out on the blade. The results show that the failure of the blade pin hole is fatigue fracture resulting from stress concentration fatigue source. There existed a bush near the exhaust edge of the blade root, where the largest stress became higher at working condition.