Stress analysis of ASME B16.5 class 900 bolted flange joints subjected to bolt-up and pressure

Abstract

Bolted flange joint assemblies are used in many industries, mainly in oil, gas, and power generation facilities. The main role of a bolted flange manifests in connecting pipes, valves, and pressure equipment to ensure the pressurized substance flowing in the pipes. Although their usage may seem simple, bolted flanges are subjected to harsh conditions that may lead to leakage and environment damage. The high pressure and high temperature of the confined fluid inside the pipes can notably compromise human health, safety, and the environment. On the other hand, structural integrity and leakage tightness are two main criteria that must be taken into consideration to prevent catastrophic failure when designing bolted flange joints. At the design level, it is crucial to compare the analytical results to the ones obtained from the numerical finite element method. Finally, from the structural integrity standpoint, it is important to examine the stresses at the junctions since they are the weakest regions of the flange. This study focuses on the evaluation of the integrity and leakage tightness of some ASME B16.5 class 900 flanges when subjected to pressure. This study investigated many parameters: the gasket contact stress, the bolt stress, the flange rotation, the radial displacement, and the distribution of the longitudinal and tangential stresses along the axial flange distance. It is to be noted that the welding neck type of flange and the spiral wound type of gasket are used to analyze all flange sizes. The flange is composed of the ring, hub, and shell that are connected at the two junctions. The welding neck flange (WNF) and the spiral wound gasket (SWG) are tightened to the recommended bolt stress of 50 ksi to prevent any possible leaks. Seven flanges of the size NPS 4, 8, 10, 14, 16, 20, and 24 of ASME B16.5 standard are modeled and simulated on ANSYS (finite element software) to obtain the results which are then compared to the analytical results to check the validity of the already developed analytical model.

Date	24 Aug 2023
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Hakim A. Bouzid (Supervisor)