Design and analysis of the flange-bolted joint with respect to required tightness and strength

Abstract

The paper presents the method of design and strength analysis of the flange-gasketed-bolted joint. In the first part, analytical calculations were carried out. Their purpose was to determine the assembly torque of nuts to achieve the desired tightness. The flanged joint designated as DN100 PN40 with two different gaskets was taken into consideration. The analytical calculations were performed in accordance with the algorithm included in PN EN 1591-1. In the further step, the numerical calculations were carried out to support the analytical results. The outcome of these calculations were maps of the contact stress distribution on the gasket surface, estimation of safety factors of individual joint elements as well as determination of the flange rotation. Data from the numerical calculations were compared with the analytical results, which confirmed their satisfactory compliance. In the last stage, the experimental tests of the joint were carried out. The main results of the test were the measured values of the leakage level, tightening force of the bolt and estimated safety factors. An indirect result of the experimental measurements were maps of the stress distribution on the contact surface of the gasket, which were determined by means of the measuring film. Ultimately, based on the experimental results, it was found that the proposed analytical method of calculation and simulation of the joint by means of the finite element method was a very good tool for the design of the joint at the required tightness level.