A Simplified Modeling of Gasket Stress-Strain Curve for FEM Analysis in Bolted Flange Joint Design
Semi-metal and non-metal gaskets (spiral wound, joint sheet, etc.) are well known that their stress-strain curve shows strong nonlinearity and hysteresis. These characteristics should be considered, when we analyze the behavior of a bolted flange joint. Regarding the analysis of bolted flange joints, authors had proposed a simplified modeling method of gasket stress-strain curve for FEM analysis in the previous PVP conferences. The method approximates the nonlinearity of gasket stress-strain relation using two different linear elastic moduli in loading and unloading, respectively. This paper provides that the comparison of computed results due to the simplified analysis and the ones due to accurate nonlinear analysis that uses a nonlinear-hysteresis gasket model. This paper also proposes the guidance to determine the two linear elastic moduli for the simplified modeling. Since the simplified analysis gives a good approximation, we conclude that the method is very useful for the analysis of bolted flange joints, especially in design stage of pressure vessel flanges or piping flanges.