Gasket Stress Field Distribution Of Impact Factors And Numerical Simulation,

The bolted flanged connections are main types in petrol-chemical equipments and pipes, and gasket is important in bolted flanged connections. Under the actual working, the size and distributing of gasket stress influence the gasket's performance and the performance of seal rely on the performance of gasket. So it is useful to study the influencing factor about size and distributing of gasket stress for material use value and flange joint's prevent leaking.In this paper, the actual working condition of gasket is considered and the joint is taken as a whole to consider the effect of interaction between all parts of the joint, Normal flange of NPS4 Classl50 in ASME B16.5 is taken as an example. Numerical analysis is completed by building 3D FEA model, simulating the nonlinearity of gasket and simulating bolt pretension through the element of pretsl79. Effects of only bolt pre-tightening load and internal pressure on gasket stress are firstly studied. It can be shown from results that gasket stress distribution tends to be nonuniformity in radial and circumferential direction with the increases in internal pressure and bolt pre-tightening load; The bolt bending stress and axial extension stress cannot be ignored. Then, the bending moment is taken account for, and substituted by the equivalent co sine-distributed stress along the pipe end circumference. Effects of the external bending moment on gasket stress is studied. The results show that the gasket stress in tension side is evidently lower than that in compression side and stress drastically reduces with the increases in bending moment, so it is more reasonable for assessing the joints sealing performance with gasket stress in tension side; Numerical calculation method in this paper is compared with PVRC experiment and two results are in good agreement.