Composite Subsea Wire with High-Strength Alloy End
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Solution Overview
Problem
Long subsea power cables face mechanical failure due to poor mechanical properties of copper conductor wires, particularly at the end that supports the weight, leading to stress-related issues and the need for scaffolding, which complicates construction and is prone to tensile, dynamic, and torsional forces.
Innovation Solution
The use of electrically conductive wires with a first wire portion made of a copper-nickel-beryllium alloy for high ultimate tensile strength and a second wire portion made of nearly pure copper for high electrical conductivity, where the first wire portion is located at the end supporting the weight, reducing the need for scaffolding and enhancing mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper conductor wires are used for long subsea power cables, then electrical conductivity is maintained, but mechanical strength is insufficient leading to stress-related failure
Solution Approach 1:
The conductor wire is divided into multiple segments or strands that are twisted together. This segmentation allows individual strands to flex and distribute stress, preventing catastrophic failure of the entire conductor while maintaining electrical conductivity through the parallel path of multiple copper strands.
Solution Approach 2:
The patent employs composite construction by combining copper strands with steel core wires or aramid reinforcement. The copper provides electrical conductivity while the steel or aramid components provide enhanced tensile strength and resistance to stress-related failure, creating a composite conductor that addresses both electrical and mechanical requirements.
2Device complexity
If the end of the conductor wire supports the weight of the remaining wire, then no scaffolding is needed, but the end becomes prone to tensile forces and dynamic motion
Solution Approach 1:
The cable end is constructed with a composite structure featuring a steel wire core or aramid reinforcement surrounded by copper strands. This composite design concentrates tensile strength at the critical end support point where weight-bearing occurs, while the copper maintains electrical conductivity. The steel or aramid components specifically address the tensile forces and dynamic motion stresses.
Solution Approach 2:
The conductor is segmented into multiple strands that are individually insulated and twisted around a central core. This segmentation allows the cable end to flex and absorb dynamic motions from waves and currents, distributing tensile forces across multiple strands rather than concentrating stress at a single point, thereby preventing failure while supporting the cable weight.
3Strength
If copper-nickel-beryllium alloy is used for the first wire portion, then ultimate tensile strength is improved, but electrical conductivity is reduced
Solution Approach 1:
The patent applies local quality by using copper-nickel-beryllium alloy specifically for the first wire portion at the cable end where maximum tensile strength is required to support the cable weight, while using pure copper for the second wire portion in the middle section where electrical conductivity is the primary requirement. This spatial differentiation of material properties optimizes both strength and conductivity where needed.
Solution Approach 2:
The conductor is divided into distinct segments with different material compositions. The first segment (copper-nickel-beryllium alloy) provides enhanced tensile strength at the critical support point, while the second segment (pure copper) ensures optimal electrical conductivity for the majority of the cable length. The segmented design allows each material to perform its specialized function without compromising the other.
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 solution provides improved mechanical strength and reduced need for scaffolding, enhancing the durability and reliability of subsea power cables by distributing weight more effectively and maintaining high electrical conductivity.
Implementation Method 1
an electrically conductive wire made of a first wire portion and a second wire portion welded together
Data Source
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AI summary
An electrically conductive wire for deep water transmission includes a first wire portion and a second wire portion. The first wire portion makes up one end of the wire, and is formed from a first metal. The second wire portion is formed from a second metal. The first metal has a higher ultimate tensile strength than the second metal. The first wire portion is used to support the weight of the second wire portion, thereby allowing the electrically conductive wire to be used in underwater or subsea power cables which may be freely suspended from their origin for providing electricity to electrical devices located in deep water or ultra-deep water.