Micromechanical modelling and gasket stress evaluation in flange joints under bolt load and internal pressure

Stresses in Teflon-filled spiral wound gaskets in flange joints are analysed by an axisymmetric finite-element method using micromechanical models constructed based on layer geometry. The constituents of the gasket are represented by hyperelastic and elasto-plastic material models. The inplane and bending stiffness and the non-linearity of the gasket are considered through micromechanical modelling. The micromechanical model is validated with experimental data available in the literature. An improved gasket stress distribution across the width of the gasket is obtained under different bolt preloads and internal pressures. At lower bolt preloads, only half of the gasket is effective for sealing. The results are compared with the average gasket stress model results with bolt axial force.