Surface micro-crack initiated brittle fracture in fiber reinforced plastic rod of composite insulator

Previous studies on brittle fracture of composite insulator were concluded, and unanswered questions were analyzed. Almost all the previous studies focus on the source of corrosion medium (the acid) and the mechanical load in brittle fracture, but the stress concentration of stress corrosion fracture was neglected. Sand paper polishing in the manufacturing process of composite insulator may lead to surface micro-cracks with the depth deeper than 30 ¿m-40 ¿m on the fiber reinforced plastic (FRP) rod surface. Stress concentration caused by surface micro-crack in FRP rod and its influence on brittle fracture was noticed in experimental study. The importance of the surface micro-crack in FRP rod was verified by a series of experimental studies. An explanation of the randomness of brittle fracture in composite insulator was put forward. Finally, the actions that should be taken to prevent brittle fracture of composite insulator were emphasized.