Constant Force Expansion Lattice via Additive Manufacturing
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Solution Overview
Problem
Existing constant force expansion materials, such as rolled stainless steel ribbon, are limited in their form and application, necessitating the development of new forms of constant force expansion devices that deviate from Hooke's law.
Innovation Solution
A constant force expansion construct comprising expandable layers with longitudinal restricting beams and interconnected flexible biasing struts, produced through additive manufacturing using dual cure polymerizable liquids, allowing for increased distance between beams and adaptable shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If rolled stainless steel ribbon is used for constant force expansion, then the device can provide constant force expansion, but the form and application versatility are limited
Solution Approach 1:
The expansion device is divided into multiple expandable layers, each containing longitudinal restricting beams and interconnected flexible biasing struts. This segmentation allows the structure to expand in a controlled manner while maintaining constant force, and enables greater design flexibility for different applications.
Solution Approach 2:
The invention transitions from a two-dimensional rolled ribbon structure to a three-dimensional lattice structure with multiple expandable layers. This dimensional change enables the device to achieve constant force expansion while providing versatile forms and configurations for various applications.
2Length of moving object
If traditional constant force expansion materials are used, then the structure is simple, but the expandable ratio is low
Solution Approach 1:
The flexible biasing struts are nested between longitudinal restricting beams in multiple layers, with each layer containing compressed struts that can extend. This nested configuration allows for a high expandable ratio as the struts unfold from a compact state, while maintaining a relatively simple overall structure.
Solution Approach 2:
The flexible biasing struts are designed to be dynamically movable between compressed and expanded positions. This dynamic capability allows the structure to achieve a high expandable ratio by transitioning from a compact configuration to an expanded state, while the restricting beams provide structural guidance.
3Adaptability or versatility
If additive manufacturing is used to produce the expansion construct, then shape versatility is increased, but manufacturing process complexity increases
Solution Approach 1:
The invention combines multiple components (longitudinal restricting beams, flexible biasing struts, and expandable layers) into a single integrated construct that can be produced by additive manufacturing. This merging of components into one manufacturable unit enables shape versatility through digital modeling while simplifying the manufacturing process by eliminating assembly steps.
Solution Approach 2:
The additive manufacturing process allows for easy modification of geometric parameters in the digital model, enabling shape versatility. By changing parameters in the computational design, different configurations can be produced without altering the fundamental manufacturing process, thus maintaining ease of manufacture while achieving design flexibility.
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 enables the creation of devices with a higher expandable ratio and versatility in shape, addressing the limitations of traditional materials by providing a non-Hookean behavior suitable for diverse mechanical and biomedical applications.
Implementation Method 1
a plurality of interconnected flexible biasing struts connecting the longitudinal restricting beam of one expandable layer to another longitudinal restricting beam in a next adjacent expandable layer, the biasing struts being biased toward a compressed position and being movable between the compressed position and an expanded position
Implementation Method 2
forming an intermediate object by additive manufacturing (preferably by stereolithography, and most preferably by continuous liquid interface production) with a dual cure polymerizable liquid
Implementation Method 3
further curing the intermediate object, optionally but preferably by heating, to produce the construct
Data Source
AI summary
A constant force expansion construct includes a plurality of expandable layers, each expandable layer including: (a) a longitudinal restricting beam; and (b) a plurality of interconnected flexible biasing struts connecting the longitudinal restricting beam of one expandable layer to another longitudinal restricting beam in a next adjacent expandable layer, the biasing struts being biased toward a compressed position and being movable between the compressed position and an expanded position in which a distance between successive longitudinal restricting beams is increased.