Analysis of the mechanical properties of a reinforced thermoplastic pipe (RTP)

Abstract

This paper describes the analysis of a long length reinforced thermoplastic pipe. For this new class of pipe, which is constructed of a polyethylene liner pipe over wrapped with two layers of non-impregnated twisted aramid cords, peculiar deformation behaviour was observed when a pipe was pressurised. This behaviour was found to be a result of a difference in cord-slack between the two reinforcement layers in conjunction with an unbalanced torsion moment generated by the two reinforcing layers. Cord slack is a certain surplus length of the reinforcing cords relative to the pipe geometry. The cord-slack is estimated for the two different layers and first incorporated into an earlier published model, based on a plane stress characterisation. As no substantial improvement has been achieved by this approach, a new model based on a plane strain characterisation is introduced. This model shows good agreement with the experimentally determined strains for the hydrostatic pressure load-case. q

Galvanically Stimulated Degradation of Carbon-Fiber Reinforced Polymer Composites: A Critical Review

“…CFRP is also used as an electromagnetic interference shield [36,37,38], electric discharge, and lightening strike protection on modifications to enhance electrical conductivity [39], sports products [40], in the maritime industry in boats, ships, and submarines [41,42,43,44], and as a corrosion resistant and reinforcing liner in pipes. In the offshore oil and gas industry it is used in the repair of corroded and mechanically-damaged onshore pipelines in which the predominant load is internal pressure [45,46,47,48,49,50,51]. In addition to good strength-to-weight ratios of CFRP’s, a potential for self-healing (i.e., recovery of mechanical and other properties post damage) has been demonstrated [52,53].…”

The Structure and Performance of Short Glass Fiber/High-Density Polyethylene/Polypropylene Composite Pipes Extruded Using a Shearing–Drawing Compound Stress Field

“…As a result, the circumferential strength of the pipe made using traditional manufacturing methods is far lower than its axial strength, and it is difficult to satisfy the practical demand for higher circumferential strength of the thin-walled tube under hydrostatic pressure. Although there have been many reports in the research of polymer pipe [28,29,30,31,32,33,34,35,36,37,38,39,40,41,42], these studies have not been able to effectively realize the self-enhancement of the pipe’s circumferential strength without reducing its axial strength, especially the coincident self-enhancement of the pipe’s axial and circumferential strength.…”

Behavior of Reinforced Thermoplastic Pipe (RTP) under Tension

“…The inner layer provides a leak-proof capacity and corrosion resistance for the transported fluid. The outer layer is used to protect the fiber layers from external damage (Kruijer et al, 2005). Nowadays, RTP has been increasingly applied as a significant alternative to conventional steel pipes in the oil and gas industry.…”