Underwater Cable Protection Assembly with Modular Bend Stiffener
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Solution Overview
Problem
Existing solutions for protecting elongate members, such as power cables, from damage during installation and operation in offshore wind farms are inadequate, particularly due to issues with bend stiffeners and J/I-tubes, which can be damaged during installation and are costly, and current cable protection assemblies have asymmetrical properties and stress concentrations.
Innovation Solution
A protection assembly comprising a bend protection device and a retaining device with a mechanical clamp for secure attachment to the support structure, allowing for automatic engagement and secure mounting, and moulded polymer bend stiffeners that can be easily assembled in a chain, reducing manufacturing and transportation costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If J-tubes or I-tubes are used to protect cables, then cable protection is improved, but installation cost and complexity increase significantly
Solution Approach 1:
The protection assembly is divided into separate modular components: a retaining device with engagement features, a bend stiffener, and a bend restrictor. These can be assembled in sequence around the cable without requiring complex pre-installed tubes, simplifying installation while maintaining protection.
Solution Approach 2:
The retaining device is designed with pre-formed engagement features (such as lugs or hooks) that can be attached to the support structure before cable installation, creating a ready-made mounting point that simplifies the overall installation process.
2Reliability
If bend stiffeners are used to prevent over-bending, then cable protection is improved, but manufacturing and transportation costs increase
Solution Approach 1:
The bend stiffener uses a flexible material with optimized mechanical properties that provides sufficient stiffness to prevent over-bending while remaining lightweight and easy to manufacture. The material parameters are tuned to achieve the required protection at lower cost.
Solution Approach 2:
The bend stiffener is constructed as a flexible sleeve or wrap that can be easily manufactured and transported, rather than a rigid heavy structure. This flexible design maintains protection functionality while reducing manufacturing and logistics costs.
3Reliability
If mechanical clamps are used for secure attachment, then retention reliability is improved, but device complexity increases
Solution Approach 1:
The retaining device incorporates self-engaging features such as spring-loaded fingers or cam-actuated latches that automatically secure to the support structure without requiring complex external fastening mechanisms, achieving reliable retention with minimal complexity.
Solution Approach 2:
The retention system uses simple intermediary elements like friction surfaces or elastic deformation zones that provide secure attachment through passive mechanical interaction, avoiding the need for complex active fastening mechanisms.
Data Source
AI summary
A protection assembly for mounting in an underwater support structure includes at least one bend protection device coupled to a retaining device so that together they provide a through-going passage for receiving an elongate member which is to be protected. The elongate member passes through a support structure opening, and the retaining device is configured to be received in the support structure opening and to engage with the support structure to resist subsequent withdrawal from it. Installation of the protection assembly includes grasping the protection assembly with a releasable clamp, arranging a pulling line to pass through the support structure opening to the mechanical clamp and securing the pulling line to the mechanical clamp, drawing the retaining device of the protection assembly into the support structure opening using the pulling line and engaging the retaining device with the support structure, and releasing the clamp from the protection assembly.