Stress intensity factor calculation of surface crack on porcelain post insulator using finite element method

Fracture accidents of porcelain post insulator at lower stress level indicates that critical stress is not good enough to estimate the mechanical strength of porcelain post insulator. Because the critical stress creation is based on practical experiences rather than a rigorous inference of mathematics and physics. Therefore, further research on fracture properties and mechanism of porcelain post insulator based on linear elastic fracture mechanics was carried out in this paper, and stress intensity factor was proposed as fracture creation of porcelain post insulator. Stress intensity factor of porcelain post insulator is related to its defect size and applied load. When stress intensity factor at crack tip exceeds fracture toughness, the crack will propagate until the porcelain post insulator fracture. And fracture toughness of porcelain post insulator is all about its material and has nothing to do with its structure, stress, and internal defects. In this study, the influences of location, depth, depth-length ratio of defect and applied load on stress intensity factor of porcelain post insulator were discussed using finite element analysis, and fracture properties and mechanism of porcelain post insulator were revealed. The achievements of this paper are instructive for design, diagnostics and monitoring of porcelain post insulator.