Flexible Pipe Bridging Tape Element for Polymer Layer Protection
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Solution Overview
Problem
Flexible pipes used in deep and ultra-deep water environments face challenges due to extreme conditions such as high pressures and temperatures, leading to potential pipe blockage and increased risk of failure, particularly from microcrazing and microcracking in polymer layers under radial expansion, which can result in loss of pressure containment and reduced lifetime.
Innovation Solution
An elongate tape element is used to form a collapse-resistant layer in the flexible pipe body, alternately wound with a collapse-resistant tape in a helical manner, featuring a wing span three times the maximum gap width between windings and a body portion extending at least 2% along the radial length of the gap, acting as a bridging element to distribute contact stresses uniformly and prevent polymer layer deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the polymer layer undergoes radial expansion under high internal pressure, then the pipe can contain pressure effectively, but the polymer material deforms and creeps into the gaps of the overlying armour layer causing microcrazing and microcracking
Solution Approach 1:
A bridging element is introduced as an intermediary component between the polymer barrier layer and the pressure armour layer. This bridging element spans the gaps between adjacent windings of the pressure armour layer, preventing direct contact and interaction between the polymer layer and the gap edges, thereby eliminating the cause of microcrazing and microcracking while maintaining pressure containment
2Strength
If thicker and stronger materials are used for pressure armour layers, then load response and performance improve, but the weight of the flexible pipe increases
Solution Approach 1:
Instead of uniformly increasing the thickness and strength of the entire pressure armour layer, the invention applies local reinforcement through bridging elements positioned specifically at the gaps between windings where stress concentration occurs. This localized approach improves structural integrity at critical points without adding excessive weight throughout the entire pipe structure
3Reliability
If internal pressure is increased to test pipe strength, then factory acceptance test reliability improves, but polymer layer deformation and creep into armour gaps worsens
Solution Approach 1:
The bridging element is installed before the pipe undergoes pressure testing or service pressure loading. This preliminary structural modification prevents the harmful effect of polymer creep into gaps from occurring in the first place, allowing the pipe to withstand high pressure tests and operational pressures without developing microcrazing or microcracking defects
Data Source
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AI summary
An elongate tape element, a flexible pipe body and method of producing a flexible pipe body are disclosed. The tape element (508) has a cross-sectional profile comprising a body portion (510) for being positioned between collapse resistant tape windings (501) such that each body portion (510) lies at least partially in a gap (512) between adjacent collapse resistant tape windings (501); and at least one wing portion (516) extending from an end region of the body portion, the at least one wing portion configured to span the gap and respectively abut with a radially inner surface of an adjacent collapse resistant tape winding.