Double-Rope Core-Cover Structure for Strength and Bendability
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Solution Overview
Problem
Existing double rope structures with a core material that is not adequately twisted are vulnerable to bending or torsion, compromising their durability and strength per cross-sectional area.
Innovation Solution
A double rope structure comprising an inner core made of high strength and high modulus fibers with a suitable gap between the inner core and outer cover, controlled by a specific inner-and-outer-layer suitability formula, enhances both bending durability and strength per cross-sectional area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the inner core is made of high strength and high modulus fibers to improve strength, then the strength per cross-sectional area is improved, but the bendability deteriorates due to insufficient twisting
Solution Approach 1:
The patent applies parameter changes by precisely controlling the twisting parameters of the inner core (number of strands, twisting angle, twisting force) to achieve optimal balance between strength and bendability. The inner core is twisted 1-3 times to create sufficient friction engagement with the outer cover while maintaining the structural integrity and strength properties of the high strength and high modulus fibers.
Solution Approach 2:
The patent uses composite materials by combining high strength and high modulus fibers in the inner core with general-purpose fibers in the outer cover. This composite structure allows the inner core to provide strength while the outer cover provides flexibility and bendability, resolving the contradiction between these two properties.
2Ease of operation
If the inner core is twisted adequately to improve bendability, then the bendability is improved, but the strength per cross-sectional area deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the twisting parameters within a specific range (1-3 times) to achieve the optimal balance point where sufficient twisting provides bendability while excessive twisting that would compromise strength is avoided. This precise parameter control resolves the contradiction between the two opposing requirements.
3Ease of operation
If the inner core is made soft to improve ease of manipulation, then the ease of manipulation is improved, but the vulnerability to bending or torsion increases
Solution Approach 1:
The patent uses composite materials with the inner core made of high strength and high modulus fibers that are twisted 1-3 times. This composite construction provides sufficient friction engagement with the outer cover for ease of manipulation while the twisted structure creates mechanical interlocking that prevents vulnerability to bending or torsion.
Solution Approach 2:
The patent applies parameter changes by controlling the twisting parameters (1-3 times) to achieve optimal friction engagement for ease of manipulation while preventing the inner core from becoming too soft or vulnerable. This parameter optimization resolves the contradiction between manipulability and resistance to deformation.
Data Source
AI summary
Provided is a double rope structure which comprises an inner core and an outer cover. In the double rope structure, the inner core includes high strength and high modulus fibers with a yarn tenacity of 20 cN/dtex or more and yarn elastic modulus of 400 cN/dtex or more, and an inner-and-outer-layer suitability represented by the following formula (1) is 0.70 to 1.20. Formula (1): (a2/b2)/Vf×100. In the formula (1), a represents the diameter of the outer periphery of the inner core, b represents the diameter of the outer periphery of the outer cover, and Vf represents the volume ratio (%) of the volume of the inner core to the total volume of the inner core and the outer cover.