Hybrid Cable Tensile Element for Deep Deployment and End Fittings
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Solution Overview
Problem
Existing submarine cables face limitations in depth deployment due to high weight and elongation under tensile stress, requiring stronger gripping forces and risking crush failure, especially when made with steel elements, and polymeric composites lack plastic deformation for end fittings.
Innovation Solution
A cable design featuring a fibre reinforced polymeric composite core partially or entirely sheathed by a metal sleeve, providing a tensile element with suitable plastic deformation and crush resistance, using a metal sheath covering at least 30% of the cross-section area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel tensile members are used to provide tensile strength, then the cable can sustain high tensile loads, but the cable weight increases significantly
Solution Approach 1:
The patent applies composite materials by combining fibre reinforced polymer (FRP) with a metallic sheath to create a hybrid tensile element. The FRP core provides high tensile strength with low weight, while the metallic sheath adds structural integrity and enables plastic deformation. This composite structure resolves the contradiction by achieving the required tensile strength without the excessive weight of solid steel members.
Solution Approach 2:
The patent applies local quality by using different materials in different regions of the tensile element. The core region uses lightweight FRP for tensile strength, while the outer surface uses metal sheath for structural properties and deformability. This spatial differentiation of material properties allows the cable to meet multiple requirements simultaneously without uniform weight increase.
2Weight of moving object
If cable weight is reduced by using polymeric composite materials, then deployment depth can be increased, but the cable loses plastic deformation capability
Solution Approach 1:
The patent uses composite materials where the FRP core provides weight reduction and tensile strength, while the metallic sheath restores plastic deformation capability. The metal sheath acts as a deformable skin that can be crimped or shaped during manufacturing and installation, giving the otherwise brittle composite material the necessary formability for practical cable production and termination.
Solution Approach 2:
The metallic sheath serves as an intermediary layer between the FRP core and the external environment. It mediates the deformation requirements by absorbing the plastic deformation demands during manufacturing and installation, protecting the FRP core from direct mechanical processing while still enabling the necessary shaping operations.
3Strength
If steel tensile members are used, then the cable has sufficient crush resistance, but the gripping force required from the payoff system increases
Solution Approach 1:
The composite structure with metallic sheath provides adequate crush resistance through the rigid outer metal layer, while the overall lighter weight of the FRP-core construction reduces the total cable mass. This weight reduction directly decreases the gripping force requirement at the payoff system, resolving the contradiction between maintaining crush resistance and reducing payload weight.
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 design allows for deeper deployment with reduced weight and elongation, maintaining strength and enabling easier handling and connection to end fittings, while retaining the durability of metal elements.
Implementation Method 1
a fibre reinforced polymeric composite core having an elastic modulus of at least 70 GPa
Implementation Method 2
They can only be substantially elastically deformed. The plastic deformation is especially sought when the tensile members are plastically deformed in end fittings
Data Source
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AI summary
It is disclosed a cable comprising an elongated tensile element having a cross section area and comprising a fibre reinforced polymer composite core having an elastic modulus of at least 70 GPa and a sheath at least partially covering the composite core, the sheath being made of metal and being at least 30% of the cross section area of the tensile element.