航空发动机反推力装置安装座断裂分析

Fracture Analysis of Mounting Seat of an Aeroengine Reverse Thrust Device

在某发动机反推力装置整机试验过程中,1处作动筒安装座发生断裂。为确定故障原因,对断裂安装座进行宏观检查、断口分析、材质分析及有限元分析等。结果表明:安装座前侧安装边棱边与座身转接处首先发生高周疲劳断裂,该处断裂后造成构件结构失稳,在试验载荷的进一步作用下导致另外2个安装边发生瞬时断裂;疲劳源区存在的缩孔缺陷导致该处产生应力集中,对安装座过早疲劳开裂有促进作用;合金成分中Cu元素含量超标导致组织中析出大量θ脆性相,从而降低了合金强度,这也是安装座过早疲劳开裂的原因。对铸造工艺和无损检测工序提出了改进建议以避免此类故障再次发生。

During the overall test of a reverse thrust device of an engine,a fracture occurred in the mounting seat of the actuating cylinder.In order to determine the cause of the fracture,macro-inspection,fracture analysis,material analysis and finite element analysis were carried out on the fracture mounting seat.The results show that the high-cycle fatigue fracture occurs first at the interface of the front side and the dado of the mounting seat,and the structural instability of the member is caused by the fracture.The further action of the test load resulted in the instantaneous fracture of the other two mounting edges.The shrinkage porosity defects in the fatigue source region lead to the stress concentration,"which can promote the premature fatigue cracking of the mounting seat.The excessive content of Cu in the alloy composition leads to the precipitation of a large number of θ brittle phases,thus reducing the strength of the alloy,which is also the reason for the premature fatigue cracking of the mounting seat.Suggestions for improvement of casting process and non-destructive testing process are put forward to avoid the recurrence of such failure.