Airborne Wind Power Tether with Segmented Load-Bearing Layer
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Solution Overview
Problem
Airborne wind power station tethers face challenges with high tensile forces and radial compression, leading to plastic deformation and failure, while existing solutions are either heavy and inefficient or have short lifetimes due to inadequate protection against mechanical stress.
Innovation Solution
An electric energy transmission tether with a load-bearing layer radially outside the conductors, comprising tensile and compression-resistant sublayers, and semi-conductive layers for efficient energy transmission, along with a lightweight design to minimize weight and diameter, and a slip/antifriction layer to reduce mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electric conductors are used in the tether, then electric energy transmission is enabled, but the conductors plastically deform and break under high tensile forces
Solution Approach 1:
The tether is segmented into functionally distinct layers: an inner core with electric conductors for energy transmission, and an outer load-bearing layer for mechanical strength. This segmentation allows each layer to optimize for its specific function without compromising the other.
Solution Approach 2:
The tether uses composite material construction with different materials serving different purposes: electric conductors (copper or aluminum) for electrical function, elastic material for flexibility, and load-bearing material for mechanical strength. This composite approach resolves the contradiction between electrical conductivity and tensile strength.
2Strength
If the tether is made thicker to resist tensile forces, then mechanical strength is improved, but weight and wind resistance increase reducing power production efficiency
Solution Approach 1:
The tether employs composite materials where the load-bearing layer uses high-strength, low-density materials to provide mechanical strength without excessive weight. The separation of electrical and mechanical functions allows optimization of each aspect independently.
Solution Approach 2:
By segmenting the tether into functional layers, the design achieves strength through the outer load-bearing layer while keeping the inner conductor layer minimal, thus reducing overall weight compared to a solid thick construction.
3Ease of operation
If the tether is wound up on a drum, then retrieval and storage is enabled, but radial compression forces cause plastic deformation of conductors
Solution Approach 1:
The elastic material surrounding the conductors acts as a cushioning layer that absorbs and distributes radial compression forces during drum winding, protecting the conductors from plastic deformation before damage can occur.
Solution Approach 2:
The composite structure with elastic material providing radial support and compression resistance protects the conductor layer during operational phases including drum winding, ensuring conductor integrity while enabling easy retrieval operations.
4Strength
If a high strength core is used to absorb tensile forces, then mechanical strength is improved, but the tether becomes thick and heavy increasing ground station weight and inertia
Solution Approach 1:
The tether segments mechanical strength functions to the outer load-bearing layer while keeping the conductor core minimal, reducing the overall mass that contributes to ground station inertia compared to a traditional heavy core construction.
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 tether effectively resists tensile forces, limits axial elongation, and protects against radial compression, enhancing the lifespan and efficiency of energy transmission while reducing weight and wind resistance.
Implementation Method 1
an elastic core (4) made of an elastic, non-metallic material... The load bearing layer (10) limits the axial elongation of the elastic core (4)
Implementation Method 2
The load bearing layer (10) comprises a compression resistant layer (25) for absorbing radial compression forces
Implementation Method 3
a first semi-conductive layer (6) being arranged between the first layer of electric conductors (5) and the electric insulation layer (7)... and a second semi-conductive layer (8) being arranged between the electric insulation layer (7) and the second layer of electric conductors (9)
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
An electric energy transmission tether (3) for an airborne wind power station (1) is provided, the tether comprising an elastic core (4), a first layer of one or more electric conductors (5) helically wound around the elastic core (4), an electric insulation layer (7) surrounding the first layer of electric conductors (5), a second layer of one or more electric conductors (9) helically wound around the electric insulation layer (7), and a load bearing layer (10) surrounding the second layer of electric conductors (9), for absorbing tensile forces and radial pressure forces acting on the tether.