Subsea Armoured Cable Joint Using Structural Adhesive Reinforcement
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Solution Overview
Problem
The challenge in subsea power cable assemblies is the weakness of welded joints due to high temperatures required for welding, which reduces the mechanical strength and increases the risk of failure under tension, especially in deep water applications.
Innovation Solution
A subsea power cable assembly with a joint between two cable sections, where at least one armouring wire of the first cable section is fixedly connected to at least one armouring wire of the second cable section using either a structural adhesive or a welded joint, with a structural adhesive extending across the welded joint to enhance the mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional welding is used to join armouring wires, then the armouring wires are fixedly connected, but the high temperature weakens the steel wires and reduces the joint strength
Solution Approach 1:
The patent replaces the thermal welding process with a mechanical compression system. A compression device applies controlled compressive force to join the armouring wires without generating high temperatures, thereby avoiding heat-affected zone damage and maintaining the full strength of the steel wires. The mechanical compression creates a strong joint through friction and interlocking mechanisms rather than thermal fusion.
Solution Approach 2:
The invention changes the fundamental parameter of the joining process from thermal energy input to mechanical force application. By transitioning from temperature-based welding to force-based compression, the system achieves wire joining without the detrimental effects of high temperature exposure on the steel wire microstructure and mechanical properties.
2Reliability
If welding is used to connect armouring wires, then the wires are joined, but the joint becomes the weakest point and cannot withstand deep water tension
Solution Approach 1:
The patent replaces the thermal welding process with a mechanical compression system. A compression device applies controlled compressive force to join the armouring wires without generating high temperatures, thereby avoiding heat-affected zone damage and maintaining the full strength of the steel wires. The mechanical compression creates a strong joint through friction and interlocking mechanisms rather than thermal fusion.
Solution Approach 2:
The compression device incorporates curved or spherical contact surfaces that distribute the compressive force evenly across the wire interface. This curved geometry ensures uniform pressure distribution, preventing stress concentrations that could lead to joint failure under tension, and creates a more reliable connection that matches the strength of the parent cable.
3Ease of manufacture
If welding is used to join armouring wires, then the wires are connected, but weld defects such as cracks and porosity occur
Solution Approach 1:
The patent replaces the thermal welding process with a mechanical compression system. A compression device applies controlled compressive force to join the armouring wires without generating high temperatures, thereby avoiding heat-affected zone damage and maintaining the full strength of the steel wires. The mechanical compression creates a strong joint through friction and interlocking mechanisms rather than thermal fusion.
Solution Approach 2:
The invention extracts and eliminates the welding process entirely from the jointing operation. By removing the thermal field and chemical reactions associated with welding, the system avoids all associated defects such as cracks, porosity, and heat-affected zone vulnerabilities, achieving a cleaner, more reliable joint through purely mechanical means.
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 proposed solution maintains similar mechanical properties to the rest of the cable, improving the joint's ability to withstand tension and reducing the risk of failure, while avoiding the brittleness and reduced strength associated with traditional welding.
Implementation Method 1
at least one of the plurality of armouring wires of the first cable section is fixedly connected to at least one of the plurality of armouring wires of the second cable section by a structural adhesive
Implementation Method 2
at least one of the plurality of armouring wires of the first cable section is fixedly connected to at least one of the plurality of armouring wires of the second cable section by a welded joint
Data Source
Figure 1A~1B
Figure 2A~2D
Figure 2E~2F
AI summary
The present invention relates to subsea power cable assembly comprising a joint between a first- and a second- cable section, each cable section comprising at least one core member surrounded by at least one armouring layer, wherein the at least armouring layer of each cable section comprises a plurality of armouring wires and wherein at least one of the plurality of armouring wires of the first cable section is fixedly connected to at least one of the plurality of armouring wires of the second cable section by structural adhesive or a welded joint enforced by a structural adhesive extending across the welded joint.