Composite Holding Strip for Flexible Pipe Buckling Resistance
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Solution Overview
Problem
Flexible tubular pipes used for hydrocarbon transport in deep-sea environments face issues with axial compression and lateral deformation due to reverse pressure effects, leading to irreversible disorganization of traction armor threads and potential corrosion, which existing solutions fail to adequately address.
Innovation Solution
A flexible tubular pipe design incorporating an internal tubular structure with a waterproof sheath and pressure vault, an external traction structure with armor threads, and a support strip made of a polymer material with mineral fibers, such as basalt or carbon fibers, which are embedded within the polymer layer to enhance resistance and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If organic fibers (aramid) are used in the reinforcement strip, then the pipe resists radial buckling and swelling, but the fibers are susceptible to hydrolysis and degradation under harsh marine conditions
Solution Approach 1:
The patent applies composite materials by combining polymer matrix with mineral fibers (glass, basalt, or carbon) to create a reinforcement strip that simultaneously provides mechanical strength against radial buckling and chemical resistance against hydrolysis. The mineral fibers replace organic aramid fibers while maintaining the structural function, and the polymer coating protects the fiber-matrix interface from environmental degradation.
2Strength
If steel wires are used to create the support bands, then the pipe gains strength, but the weight of the pipe significantly increases
Solution Approach 1:
The patent changes the material parameters by transitioning from metallic (steel) to non-metallic (mineral fiber-reinforced polymer) materials. This substitution maintains the required mechanical strength through optimized fiber orientation and polymer matrix selection while dramatically reducing the density and overall weight of the support bands.
3Duration of action of stationary object
If the reinforcement strip is coated with polymer material, then the lifespan of the strip increases, but the coated strip is not protected from degradation under all operating conditions, particularly in ultra-deep waters
Solution Approach 1:
The patent enhances the polymer-coated reinforcement strip by incorporating mineral fibers within the polymer matrix to create a composite structure. This composite material provides both the polymer's protective properties and the mineral fibers' superior resistance to hydrolysis and chemical degradation, ensuring reliability in ultra-deep water environments where conventional polymer coatings alone are insufficient.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The use of mineral fibers in the support strip significantly increases the pipe's resistance to hydrolysis, corrosion, and mechanical stress, while maintaining elasticity, thereby preventing 'bird cage' structures and extending the pipe's lifespan in harsh marine conditions.
Implementation Method 1
These mineral fibers have the advantage of being much more resistant to hydrolysis than organic fibers
Implementation Method 2
they allow the retaining bands to have high moduli of elasticity, for example, greater than 100 GPa
Implementation Method 3
When transverse stresses are added to the pipeline in a dynamic and turbulent environment, the reinforcement wires of the tensile reinforcement layers tend to buckle laterally, causing irreversible local damage to the pipeline
Data Source
Figure 1~4B
AI summary
The invention concerns a flexible tubular conduit (10) comprising a tubular inner pressure structure comprising a tubular sheath (16) and a pressure vault (18) for taking up the radial forces, and a tubular outer tensile structure comprising at least one web of tensile armour wires (22, 24), and a holding strip (28) wound in a short-pitch helix over said web of tensile armour wires (24), said holding strip (28) comprising a layer of polymer material and a plurality of strands of fibres stretched substantially in the longitudinal direction of said holding strip (28). The fibres of the strands of said plurality of strands of fibres are mineral fibres, and said plurality of strands of fibres is embedded in said layer of polymer material.