Fracture Treatment of Connecting Bolts on the Top Cover of Star-flex Hub of a Helicopter
The failure phenomenon of the fracture of blade hub bolt and corresponding bushing of a star-flex hub was illustrated.By means of microscopic means,energy spectrum analysis,metallo-graphic structure inspection,the reasons from multiple aspects such as appearance fracture surface and strength were analyzed,and it was concluded that the fatigue failure of the bolt was caused by the loss of tightening torque,and the suitable treatment scheme was put forward in combination the reasons.This fault was resolved by increasing the design margin of tightening torque and strengthe-ning the monitoring of usage.