关键词: 法兰, 内开孔金属O形环, 高压, 侧壁间隙, 压缩率, 变形失效

Abstract:

Aiming at the problem of seal failure of the metal O-ring with internal holes of a pressure vessel flange under high pressure conditions, which was caused by excessive deformation of the O-ring due to unreasonable design of the flange structure, a three-dimensional cyclic nonlinear elastoplastic model was established to analyze the effects of flange side wall gap and compression ratio on the circumferential distribution of contact stress and O-ring deformation. The leakage rate of O-ring under different flange side wall gap and compression ratio was tested, the deformation characteristics of O-ring were analyzed, and the deformation failure mechanism of O-ring under high pressure and big side wall gap was discussed. The research results showed that the established finite element model can accurately simulate the mechanical behavior and deformation of O-ring, and the calculated curve had a good agreement with the experimental curve. The contact stress of O-ring was more sensitive to the flange side wall gap, reducing the flange side wall gap and increasing the compression ratio can improve the reliability of O-ring seal. O-ring was prone to necking deformation under high pressure conditions, resulting in circumferential discontinuity of contact stress and leakage. Controlling the preload clearance of O-ring and playing the restraint effect of flange side wall can improve this kind of deformation. The research results can provide a reference for the flange structure design of high pressure metal O-ring sealing with internal holes.

Key words: flange, metal O-ring with internal holes, high pressure, side wall gap, compression ratio, deformation failure