Failure Analysis of the FX-4 Rubber O-Ring in the Graphite Sealing Assembly

During the major overhaul of the aircraft accessory housing, oil leakage was detected at the cover plate of the DC motor bracket. Inspection revealed that the graphite sealing assembly used for sealing had failed, with one of the rubber O-ring components showing surface indentations and adhesion to the inner wall of the graphite ring. The failure of this type of sealing assembly primarily manifests in two categories: damage to the graphite sealing ring and damage to the rubber O-ring. While the former has been extensively studied, the latter has received very little attention. In this study, three experiments were conducted on the FX-4 rubber O-ring: model theory analysis, dimensional control assembly testing, and temperature influence testing. These experiments revealed the effects of design dimensions and temperature changes on the damage to the O-ring in the graphite seal assembly.