Prediction of the durability of a gasket operating in a bolted-flange-joint subjected to cyclic bending

The article presents the results of experimental tests regarding the assessment of the tightness of a gasketed-flange-bolted joint with an elastomer-fiber gasket, which is a sealing node of the industrial pipeline system. In the course of the tests, the joint was subjected to three-point (zero based cycle) bending within an amplitude from 0.2 to 0.6 mm, with a frequency of 10 Hz, and in a range of 100 k cycles. In selected points of the joint's deformation, measurements of the bolts' tension, tightness level, as well as the force causing the bending of the pipeline were made with the aim of determining the absorbed and dissipated energy in the gasket material. On the basis of the analysis of the obtained results it was concluded that along with the growth of vibration cycles and bending amplitude, leakage gradually increases, and at higher amplitudes it stabilizes and remains at a constant level. Moreover, it was found that there is a connection of some sort between leakage stabilization and dissipated energy in the gasket material. Numerical calculations by means of the Finite Element Method, simulating the working conditions of the gasket in the bent flange-bolted joint, were also used in the research. The outcomes of the calculations allowed the stress and strain of the gasket at the maximum bending of the joint to be determined. In the final part of the work, a half empirical model for predicting the number of joint deformation cycles at which leakage remains at a constant level was proposed.

Automated summary

The article presents experimental tests on the tightness assessment of a gasketed-flange-bolted joint with an elastomer-fiber gasket. It was found that increasing vibration cycles and bending amplitude leads to gradual leakage increase, which then stabilizes at higher amplitudes. Numerical calculations were used to determine the stress and strain of the gasket at maximum bending, and a semi-empirical model was proposed to predict the number of joint deformation cycles at which leakage remains constant.