Analysis of fiber reinforced plastic bolted flange joints

Abstract

Fiber Reinforced Plastic (FRP) composites are extensively used in the areas of pressure vessels and piping and FRP bolted flange joints have experienced a spectacular development to provide continuity for the flow of fluid through piping systems. In spite of the increased use of FRP composites in bolted flange joints and the good knowledge of these structures and their material behavior the procedure used for their design is still that of metallic flanges. There is a major concern to appropriately address the anisotropic behavior of composite materials in a flange design. Therefore, it is necessary to make a precise evaluation of the bolt and gasket loads in order to be able to predict the integrity of FRP bolted flange joints. This thesis presents two analytical model cases; one with the flange hub and the other one without the flange hub. These models are supported by numerical finite element modeling and experimental test data. The study treats FRP bolted flange joints integrity and leak tightness based on the anisotropy and flexibility analysis of all joint elements including the gasket, bolts, and flanges. In the analytical models for the flange with and without the hub, the composite flanges are subdivided into three major categories, namely: ring flange, hub, and shell. The experimental study was carried out on a well-equipped test bench, used for Hot Blow out test of PTFE gaskets. The rig was modified to accommodate an NPS 3 FRP bolted flange joint designed according to ASME BPV Code Section X. Furthermore, three different numerical models based on 3D anisotropic layered shell and solid element models were conducted to compare and verify the results obtained from analytical and experimental approaches. In spite of the rigorous mathematical analysis and complexity of the laminate composite flange, comparing the results proved that the proposed analytical models for FRP flanges with and without the hub, are efficient, accurate and reliable in predicting the longitudinal and tangential stress distributions on the flange surface and radial displacement of the flange. Moreover, the results demonstrated that the FE model which is developed for FRP flanges with and without the hub can depict the true behavior of FRP bolted flange joints.

Date	22 Jul 2019
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Hakim A. Bouzid (Supervisor) & Anh Dung Ngô (Co-supervisor)