Influence of loading rate on deformation behaviour and sealing performance of spiral wound gasket in flange joint

Owing to increase in the demand for power, a number of power plants have been installed in the recent past. One of the vital components in these plants is gasketed flange joint. The behaviour of gasketed flange joint is highly dependent on the deformation characteristics of gasket material. In the present study, the deformation characteristic of spiral wound gasket along thickness direction is determined experimentally for different loading rates. Gasket has high nonlinearity under both loading and unloading, with hysteresis. Based on its characteristics, the flange joint is analysed to study its performance and leakage behaviour under static condition. 3D finite element model of flange joint is developed by considering the gasket as interface entity. Finite element analysis of flange joint is performed by including the nonlinear hysteretic behaviour of gasket, under different loading rate and frictional contact between joint members. The influence of different loading and unloading rates is emphasized on the sealing performance of flange joint using leakage pressure. The gasket deforms more when loaded at low rate. This phenomenon also affects the ability to withstand internal fluid without leakage. The maximum safe pressure without leakage increases, when gasket is loaded and unloaded at low rate.