Resilient Cable With Compliant Layer for Defect Prevention
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Solution Overview
Problem
Existing electrical power cables are prone to defects during manufacture and operation, particularly in harsh environments, leading to water and oxygen penetration, which can cause degradation and eventual failure, especially in inaccessible locations like underground or underwater installations.
Innovation Solution
The development of an electrical power cable with a resilient external layer comprising a compliant layer and a tough layer, where the compliant layer has a shear loss modulus of at least 0.3 MPa at 296 K and the tough layer has a fracture toughness of at least 1 MPa m½ at 296 K, along with a self-healing layer to prevent defect propagation and allow for mechanical deformation without failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective outer sheath is used to protect the cable, then the cable is protected from external damage, but defects may still form in the sheath during manufacture and installation which are difficult to detect and can develop into major defects
Solution Approach 1:
The patent applies beforehand cushioning by incorporating a compliant layer with high shear loss modulus (at least 0.3 MPa at 296 K) beneath the protective outer sheath. This compliant layer acts as a cushion that absorbs mechanical energy and mitigates stress concentrations before defects can propagate through the sheath, preventing minor defects from developing into major failures during manufacture, installation, and operation.
Solution Approach 2:
The patent employs composite materials by creating a multi-layer structure consisting of the protective outer sheath combined with a compliant layer having specific mechanical properties (shear loss modulus ≥ 0.3 MPa). This composite structure combines the protective function of the sheath with the energy-absorbing characteristics of the compliant layer, achieving both protection and defect mitigation simultaneously.
2Reliability
If the cable structure is made more resilient with additional layers, then the cable can absorb deformation energy and prevent defect propagation, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies parameter changes by specifying precise mechanical property thresholds for the compliant layer (shear loss modulus of at least 0.3 MPa at 296 K). By defining clear parameter ranges, the patent enables manufacturers to select from various materials that meet the criteria, simplifying the manufacturing process while ensuring the required defect prevention performance is achieved.
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 cable undergoes mechanical deformation without defect formation, absorbs energy, and prevents water penetration, extending its operational lifetime and reducing replacement costs by allowing self-repair of minor defects, thereby enhancing durability and reliability in challenging environments.
Implementation Method 1
the compliant layer disposed directly next to the tough layer which absorbs the energy of deformation due to its mechanical loss characteristics
Implementation Method 2
a compliant layer having a shear loss modulus of at least 0.3 MPa at 296 K
Implementation Method 3
a self-healing layer extruded around and surrounding the core
Data Source
Figure 1
Figure 2~3
Figure 4a~4b
AI summary
The invention relates to resilient cables, their uses and to methods of manufacturing such cables.