Design and Analysis of Composite Pipe Joints under Tensile Loading

Abstract

Composite pipe has been used in transporting corrosive fluid in many chemical processes in the petrochemical and pulp and paper industries. More recently, composite pipe has further gained its importance in the offshore oil and gas industry due to its light-weight, corrosion resistance, and the new invention of Tension Leg Platforms (TLPs) for deep-water oil and gas exploration and production. Despite the fact that it has been estimated that there is one joint for every four feet of composite pipe installed for marine applications, the joints are the weakest link in a composite piping system. In order to understand the mechanical behavior and to provide analytical design tools for composite pipe joints, an analytical model was developed based on the first-order laminated anisotropic plate theory. In this developed model, a three-component joint system consisted of coupling, adhesive, and pipe was used to model different types of composite pipe joints such as adhesive-bonded socket joints, butt-and-strap joints, and heat-activated coupling joints. Results obtained from the developed model including adhesive peel stress and shear stress distributions were compared with finite element models. Good correlations were found. With this developed model, the influence of joint length and coupling design on the joint performance was determined.