Curved Micro-Truss Structure via Photopolymerization
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Solution Overview
Problem
Existing lightweight sandwich structures face challenges in forming complex curvatures without resorting to costly manufacturing techniques that may damage the structural integrity, as current materials like foams, honeycomb structures, and metal lattice structures have limitations in conforming to specific shapes.
Innovation Solution
A three-dimensional, ordered micro-truss structure is formed by patterning polymer waveguides to create a curved net-shape structure, which involves using a photo-monomer, a mask with apertures, and collimated light to create polymer struts that can be elastically deformed and thermally post-cured to achieve the desired curvature, with optional metal coatings for enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If foam is used as core material, then lightweight property is achieved, but strength and stiffness are limited
Solution Approach 1:
The patent combines polymer foam core with metal lattice structures and/or carbon fiber reinforcement to create a composite sandwich structure. This composite approach maintains the lightweight advantage of foam while adding the strength and stiffness of metal and carbon fiber components, resolving the contradiction between light weight and structural strength.
2Strength
If closed-cellular foam is used as core material, then strength and rigidity are improved, but fluid flow capability deteriorates
Solution Approach 1:
The patent employs open-cellular foam structures or foam with controlled porosity that allow fluid to flow through the core material while maintaining adequate strength and rigidity. The porous structure provides fluid passage channels without completely sacrificing mechanical properties, resolving the contradiction between strength and fluid flow capability.
3Shape
If honeycomb structure is formed to achieve particular curvature, then shape conformity is improved, but manufacturing complexity increases for complex curvatures
Solution Approach 1:
The patent divides the core structure into modular segments or layers that can be independently formed and then assembled to create complex curvatures. This segmentation allows each module to be manufactured with standard processes while the overall complex shape is achieved through modular assembly, reducing manufacturing complexity compared to forming the entire structure as one piece.
Solution Approach 2:
The patent employs flexible or adjustable honeycomb structures that can be deformed or reconfigured during assembly to achieve complex curvatures. This dynamic approach allows the structure to adapt to different geometric requirements without requiring completely different manufacturing processes for each curvature configuration.
4Shape
If metal lattice structure is plastically deformed or machined to form curvature, then shape conformity is improved, but structural integrity deteriorates
Solution Approach 1:
The patent pre-forms the metal lattice structures or sandwich panels with the desired curvature during the manufacturing process, eliminating the need for subsequent plastic deformation or machining. By incorporating the curvature into the initial forming step, the structure achieves the required shape without compromising its structural integrity through later deformation operations.
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
This method allows for the creation of lightweight structures that can conform to complex curvatures without expensive manufacturing processes, maintaining structural integrity and offering improved strength, stiffness, and thermal conductivity.
Implementation Method 1
A method of manufacturing a curved (or 'net-shape'), three-dimensional, ordered micro-truss structure includes: providing a volume of a photo-monomer; providing a mask between at least one collimated light source and the volume of the photo-monomer, the mask having a plurality of apertures; directing a collimated light beam from the at least one collimated light source to the mask for a period of exposure time, a portion of the collimated light beam passing through the apertures of the mask and into the photo-monomer to form a plurality of polymer waveguides through a portion of the volume of the photo-monomer
Implementation Method 2
heating the partially cured, three-dimensional, ordered micro-truss structure above its glass transition temperature; elastically deforming the partially cured, three-dimensional, ordered, micro-truss structure into a curved (or 'net-shape') surface
Data Source
AI summary
A curved, three-dimensional, ordered micro-truss structure including a series of first struts extending along a first direction, a series of second struts extending along a second direction, and a series of third struts extending along a third direction. The first, second, and third struts interpenetrate one another at a series of nodes. The series of first struts, second struts, third struts, and nodes form a series of ordered unit cells within the micro-truss structure. The series of ordered unit cells define a curved surface.