ON THE SPECIFICATIONS OF FLEXIBLE COMPOSITE BALL SOCKET JOINT PIPE CHARACTERIZED BY BARREL SHELL MODEL

Pipelines for deep-water application should be designed to be extremely flexible to ease the installation procedures. Such flexibility will improve the bending instabilities of reeled pipelines during spooling of initially straight or laying of initially bent pipe. Also during construction, pipeline flexibility could be exploited to connect pipelines and risers to floaters,manifolds, wellheads, buoys, and platforms. Therefore, the proposed flexible pipe is designed to be positionable and bendable enough to fit the above requirements. The pipe is comprises a series of interconnected ball-and-socket sections forming a liner
and a fluid-tight cover, one or more helical wounding layers applied to the internal liner for absorbing tension loads, and one or more additional helical wounding layers applied for absorbing bending loads. In order to form a liner, the ball-and-socket segment will passes through a die, while a thread guide applies a plurality of reinforcing threads in a particular pattern to the
exterior surface thereof to keep the segments to be snappingly engageable and maintain the pipe flexibility without significantly increasing in the thickness of the pipe wall or weight. The ball and socket segments are assumed manufactured from a lightweight composite material consisting of epoxied matrix reinforced by long continuous fibers. The socket segment was assumed a stiffer ring. Therefore, this paper will emphases on the design parameters of the ball joint that form the pipe by
modeling it as laminated composite barrel shell and examining its elastic deformations capacity under pure bending conditions (e.g., typical reeling installation condition). To this aim, a straightforward treatment of the problem is presented via using Hamilton's principle and based on the first order shear deformation theories. The solution of the laminated composite barrel shell was formulated to follow exactly a simply supported boundary condition. Finally, the in-plane stresses and inter-laminar
stresses were evaluated for wide range of loading conditions.