Tape-Spring Deployable Device with Non-Constant Cross Section
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Solution Overview
Problem
Tape-springs used in space equipment face challenges in stability and mass optimization due to non-uniform stiffness along the stress axis, leading to instability in the deployed state and inefficiencies in compactness and rigidity.
Innovation Solution
A deployable device featuring a tape-spring with non-constant cross-sectional dimensions, where at least one dimension varies along the deployment axis, combined with local reinforcements and optimized cross-sectional shapes like cylindrical, U-shaped, or 'omega' forms, to enhance stability and reduce mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the tape-spring is oversized to ensure stability in the deployed state, then stability and rigidity are improved, but mass increases
Solution Approach 1:
The patent applies local quality by varying the cross-sectional dimensions of the tape-spring along its length. The width and/or thickness are non-constant, being larger in certain regions to provide enhanced stability and rigidity where needed, and smaller in other regions to reduce mass. This localized optimization allows the structure to achieve necessary stability without requiring uniform oversizing throughout the entire tape-spring.
2Volume of moving object
If the winding radius is minimized for compactness in the stowed configuration, then compactness is improved, but the available space for deployment is reduced
Solution Approach 1:
The patent employs dynamics by designing a tape-spring with non-constant cross-sectional dimensions that can transition between a compact wound configuration and an extended deployed configuration. The varying width and/or thickness along the tape-spring length allows it to pack efficiently when stowed while providing sufficient material length and structural capability to achieve the required deployment space when unfurled.
3Strength
If the cross section is maximized for optimum rigidity in the deployed configuration, then rigidity is improved, but mass increases
Solution Approach 1:
The patent applies local quality by varying the cross-sectional dimensions of the tape-spring along its length. The width and/or thickness are non-constant, being larger in certain regions to provide enhanced stability and rigidity where needed, and smaller in other regions to reduce mass. This localized optimization allows the structure to achieve necessary stability without requiring uniform oversizing throughout the entire tape-spring.
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 achieves a 30% mass reduction while maintaining satisfactory rigidity, optimizing the mass/stiffness ratio and enabling a more compact, lighter, and efficient deployment mechanism.
Implementation Method 1
Tape-springs are known in the space field as being flexible strips that have a circular-arc cross section, the radius of curvature of which is convex on a first face and concave on a second face, these strips being capable of passing from the wound state to the unwound state essentially by virtue of their intrinsic elastic energy.
Data Source
AI summary
A deployable device includes a tape-spring capable of passing from a wound configuration about a first axis Z to a deployed configuration along a second axis X substantially perpendicular to the first axis Z, the tape-spring having two characteristic dimensions, a first characteristic dimension being the width of the tape-spring along the first axis Z, a second characteristic dimension being the thickness of the tape-spring along a third axis Y substantially perpendicular to the first axis Z and to the second axis X. At least one of the two characteristic dimensions has a non-constant value along the second axis X.