Carbon-Reinforced Submarine Working Cable for Deepwater Load Capacity

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Solution Overview

Problem

Underwater working cables face challenges in achieving high payload and low elongation while maintaining a simple structure, as traditional metallic materials used for support and reinforcement increase dead weight, reducing payload capacity and limiting depth operations.

Innovation Solution

The use of high-tensile non-metallic strands, primarily carbon fibers, embedded in a matrix and surrounded by a protective layer, combined with metallic strands for reinforcement, creates a lightweight cable with comparable tensile strength to metallic cables, enhancing payload capacity and depth operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metallic strands are used for support and reinforcement, then tensile strength is improved, but weight increases

Engineering Contradiction:
Improvetensile strengthVSAvoidcable weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies composite materials by combining carbon fiber strands with metallic strands in a single cable structure. The carbon fiber strands provide high tensile strength with low weight, while the metallic strands contribute additional strength and structural support. This composite approach resolves the contradiction by achieving high tensile strength without the full weight penalty of entirely metallic construction.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameter from purely metallic to include carbon fiber composites. By substituting some metallic strands with carbon fiber strands, the cable achieves a favorable strength-to-weight ratio. The carbon fiber strands have comparable tensile strength to steel but significantly lower density, thereby reducing overall cable weight while maintaining required strength levels.

Inventive Principle:
Principle #35Parameter changes

2Weight of moving object

If carbon fiber strands are used, then weight is reduced, but protection from external influences is worsened

Engineering Contradiction:
Improvecable weightVSAvoidmechanical damage protection
Core Design Contradiction:
Weight of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediate protective layer that surrounds the carbon fiber strands. This protective layer acts as a mediator between the carbon fiber strands and external harmful factors such as mechanical damage, water, and chemical exposure. The protective layer transfers and distributes external forces, protecting the carbon fiber strands from direct damage while allowing the cable to maintain its lightweight advantages.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a nested structure where carbon fiber strands are embedded within protective layers, which in turn are surrounded by metallic strands. This nested arrangement provides multiple levels of protection: the inner protective layer shields carbon fiber from direct contact with harsh environments, while outer metallic strands provide additional mechanical protection. This layered nesting resolves the protection issue while preserving the weight benefits of carbon fiber.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Quantity of substance

If non-metallic strands are used, then payload capacity is improved, but structural simplicity is worsened

Engineering Contradiction:
Improvepayload capacityVSAvoidcable structure
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent segments the cable structure into distinct functional zones: carbon fiber strands for primary load-bearing, protective layers for environmental shielding, and metallic strands for additional strength and structural integrity. This segmentation allows each component to be optimized for its specific function while maintaining an overall simple and systematic structure. The clear functional division simplifies manufacturing and assembly processes despite the multi-material composition.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3485498B1Submarine working cable
Publication Date: 2024.03.20 NORDDEUTSCHE SEEKABELWERKE AG
  • EP3485498B1 patent drawingFigure 1
  • EP3485498B1 patent drawingFigure 2

AI summary

Submarine working cables (10) for supplying power to submersibles, for information exchange between the submersibles and a mother station and for load handling in the manner of a crane cable for carrying the submersible, are intended to exhibit as high a load-bearing capacity as possible. At great water depths, the dead weight of the submarine working cable (10) reduces the load-bearing capacity thereof. Therefore, for great working depths, submarine working cables (10) have to be provided with an above-average large cross section of strands that can be loaded under tension. The invention provides for a part of the strands (44) of the submarine working cable (10) that absorb tensile loads to be made of a high-tensile, non-metal material, i.e. carbon. This reduces the dead weight of the submarine working cable (10), with the result that it can bear higher loads than submarine working cables (10), load-bearing, tension-absorbing strands of which are made entirely of steel.