Slit Tube Composite Edge Structure for Longer Coiling Life
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Solution Overview
Problem
Extendible members such as coiled composite masts and booms, particularly BRCs, are vulnerable to damage on the edges due to strains incurred by coiling and external impacts, leading to premature failure.
Innovation Solution
A laminated shell with reduced reinforcing fibre in edge regions and a flexible strip or cord to reinforce and stiffen these areas, using a polymer or elastomeric material that tolerates higher strains before breaking, combined with a staggered layer arrangement to distribute stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the shell is made with uniform fibre reinforcement throughout, then the structural strength is maximized, but the edge regions experience excessive strain and are vulnerable to damage during coiling
Solution Approach 1:
The patent applies local quality by varying the fibre reinforcement distribution across different regions of the shell. The edge regions have reduced fibre content compared to the central region, allowing these areas to accommodate higher strains during coiling while the central region maintains structural strength. This non-uniform distribution resolves the contradiction between overall strength and edge damage resistance.
Solution Approach 2:
The patent uses composite materials with spatially varying fibre reinforcement to create a shell that has different mechanical properties in different regions. The fibre-reinforced polymer composite allows the central region to provide structural strength while the edge regions with reduced fibre content provide strain tolerance during coiling operations.
2Duration of action of stationary object
If the amount of reinforcing fibre is reduced in edge regions, then the strain experience by fibres is reduced and cycle life increases, but the structural strength in those regions decreases
Solution Approach 1:
The patent implements local quality by creating a non-uniform fibre reinforcement distribution where edge regions have lower fibre content than the central region. This allows the edge regions to experience reduced strain during coiling cycles, extending the overall cycle life of the shell, while the central region maintains sufficient structural strength through higher fibre reinforcement.
3Reliability
If a strip of flexible material is added to edge regions, then the resistance to impact damage and strain is improved, but the device complexity increases
Solution Approach 1:
The patent applies composite materials by integrating a flexible strip material with the fibre-reinforced polymer shell. The flexible strip, made from elastomeric or viscoelastic material, is combined with the composite shell structure to provide enhanced strain tolerance and impact resistance at the edge regions, while the composite nature allows for integrated manufacturing that manages the added complexity.
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
Reduces strain and increases resistance to damage, prolonging the cycle life of the member by mitigating peak strains and impact damage.
Implementation Method 1
the flexible strip being a polymer or other ductile, elastomeric, elasto-plastic or visco-elastic material such that it tolerates higher strains before breaking in bending than the fibre reinforced body of the shell
Implementation Method 2
the flexible strip being a polymer or other ductile, elastomeric, elasto-plastic or visco-elastic material such that it tolerates higher strains before breaking in bending than the fibre reinforced body of the shell
Implementation Method 3
a laminated shell of plural fibre reinforced layers constructed and arranged to be configurable between a coiled form and an extended form
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
Extendible slit tube members and methods for manufacturing extendible slit tube members are provided.In one aspect, an extendible member (10) comprises a laminated shell (2) of plural fibre reinforced layers (P1-P5) constructed and arranged to be configurable between a coiled form and an extended form. In the extended form (12) the shell is resiliently biased in the form of an elongate tube having longitudinal edges (14) defining a slit (3) along its length and wherein the shell can be opened out at the slit to assume a flattened form in which it can be wound about an axis extending transversely to its longitudinal direction to assume its coiled form (11). In the region of one or both longitudinal edges (50), the amount of reinforcing fibre is less than in the region between the edge regions (51).In another aspect, a flexible cord(40)may be attached along the edge of a shell.