Failure analysis of right-front wheel hub rim of nose gear of a cargo aircraft

Abstract

Following a post-flight inspection of a cargo aircraft upon landing, it was discovered that the right front wheel hub rim of the nose gear had experienced a fracture. In order to determine the cause behind this fracture, a comprehensive analysis was conducted on the hub, encompassing macro-micro-morphological observation, energy spectrum analysis, microstructure examination, and mechanical testing. The findings revealed the presence of a lengthy oxide defect at a stress concentration point located on the inner corner of the hub rim. Fatigue cracks emerged at this defect site, exhibiting signs of fatigue growth, ultimately leading to high-cycle fatigue fracturing at the hub rim position. It is suggested that quality control should be strengthened during the production process of wheel hubs to avoid defects forming. Further inspection of the transition position of the wheel flange during maintenance and repair is needed to find the crack as soon as possible.