| Bolted flanged connection system is commonly used in industrial pressure vessel and pipeline. Gasket is the most important element of all. Its performance directly affects the joint sealing performance.lt is important for the research on sealing performance of gasket that the study of stress distribution under various load and size of gasket.Firstly, the general structure and type of gasket is introduced, and the important performance of gasket is expounded. An expression is calculated which is used for fitting the experiment date of homemade non-asbestos metal spiral gasket. The results show that the equation is precise enough for fitting compressive recovery curve and is of high precision.Secondly, the bolted flange joints were analyzed by using the deformation theory. An analytical formula for the flange angle was obtained based on DIN2505method. An parsing algorithm was established, which is used for calculating radial stress of homemade non-asbestos metal spiral gasket.Finally, the NPS4Class150in ASME B16.5standard flange was selected as model in this paper. Based on material nonlinear and contact nonlinear, a3D FEA model was build. The influence of pre-load, pressure and dimensions of gasket on radial stress distribution is analysed by using the method of numerical simulation. The parsing algorithm established in this paper is verified by the results of numerical simulation. The results show that the gasket stress tendency is consistent under different pre-tightening force or internal pressure. And the stress in the same site was increasing with increasing internal pressure and pre-load. The residual stress distribution of gasket is not only associated with the bolt pre-tightening force, but also with the size of the gasket. The results of analytic algorithm were basically consistent with numerical simulation, the algorithm can be used as approximate calculation method of engineering for analysising the stress distribution of non-asbestos metal spiral gasket. |
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