Failure Analysis of Airplane Control Actuator and Decision of the Initial Fragment

The switch support stand and sensor support stand of the airplane control actuator fractured after random vibration test. The failure reason of the control actuator and the initial fragment were analyzed by means of frature analysis, chemical compositions analysis, hardness test and metallographic examination. The results show that the switch support stand was the initial fragment. Switch support stand fractured firstly by quasi-cleavage, and then the sensor support stand was impacted by the fracture of switch support stand and caused the fatigue fracture of the sensor support stand. The crack existed in the switch support stand before random vibration test was the main reason for the fracture of the switch support stand.