Abstract
This study of the behaviour of high-density polyethylene umbilical hoses subjected to constant and cyclic variation of pressure and temperatures attempts to simulate the temperatures and stresses experienced in offshore operations. The hoses are used to carry fluids to the top of the wellhead and provide protection for the electrical and optical controls systems. Measurements are reported for exposures at 40℃, 70℃ and 100℃ in water, methanol and xylene, using an applied pressure of 200 bar. The changes in the physical properties of the hose were monitored by measurement of the tensile properties, dynamic mechanical thermal analysis, differential scanning calorimetry and gravimetric uptake of the fluids. Significant changes occur immediately on application of pressure and reflect changes in crystallinity. The rates and extent of the modifications depend primarily on the ageing temperature but are also influenced by the fluid. Water has little effect on the rate at which ageing occurs, whereas xylene, which is a potential solvent for high-density polyethylene, exhibits characteristics of plasticization. Methanol behaves as a weak solvent and shows characteristics intermediate between xylene and water. Burst tests carried out on the aged material show that significant loss in strength is only observed with the highest temperatures and most aggressive solvent systems. The study indicates that engineers should use pressure-aged rather than initial materials data when designing umbilical hose systems.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.