安装架接头失效分析与焊接残余应力研究

Failure Analysis of Mounting Frame Joint and Study on Welding Residual Stress

某型飞机发动机安装架T型管焊接接头在服役期间出现断裂,随后在例行检查中发现多架次飞机发动机安装架在相同位置出现裂纹,飞行训练受到严重影响,飞行安全受到严重威胁。为了探明失效原因,根据失效分析自主开发该型飞机发动机安装架的焊接修理工艺。针对该型飞机发动机安装架,首先通过扫描电镜与金相显微镜等设备确定失效原因为热影响区域附近存在大量焊接残余应力,导致焊接裂纹,该构件在服役中受到交变载荷最终导致了裂纹扩展后的疲劳断裂;然后参照现有焊接工艺在有限元软件中进行焊接仿真,通过温度场探究应力场的分布规律;最后通过X射线测试残余应力,证明仿真模型的正确,为该型飞机发动机安装架焊接修理工艺的自主开发奠定了基础。

The welded joint of T-tube of an aircraft engine mounting frame was broken during service,subsequently,cracks were found in the same position of the engine mounting frame of many aircraft during routine inspection,which seriously affected flight training and flight safety.In order to find out the cause of failure,the welding process for repairing the engine mounting frame of this type of aircraft was mainly developed by self-development according to the cause of failure.For this type of aircraft engine mounting frame,firstly,through scanning electron microscope and metallographic microscope,it was determined that the failure reason was that there were a large number of welding residual stresses near the heat affected area,which resulted in welding cracks.The component was subjected to alternating load in service that resulted in fatigue fracture after crack propagation.Then,according to the existing welding process,the welding simulation was carried out in the finite element software,and the distribution law of the stress field was explored through the temperature field.Finally,the residual stress was tested by X-ray to prove the correctness of the simulation model.It laid a foundation for the independent development of welding repair technology for this type of aircraft engine mounting frame.