Open Cellular Sandwich Structures With Sealed Edges

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Solution Overview

Problem

Conventional sandwich structures with closed-cell cores are not suitable for applications requiring fluid flow, as they cannot seal directionally open cores effectively, leading to potential damage or corrosion, and existing sealing methods are costly and labor-intensive.

Innovation Solution

The development of sandwich structures with an open cellular core and a fluid-tight seal, achieved by using a contoured first facesheet with an ordered three-dimensional microstructure core defined by interconnected polymer optical waveguides, and a second facesheet that cooperates to form a sealed periphery, along with methods involving photo-monomer irradiation to create a cured polymer border and microstructure core.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a closed-cell core is used in sandwich structures, then structural strength and stiffness are improved, but fluid flow through the core is prevented

Engineering Contradiction:

Improvespecific strength and stiffnessVSAvoidfluid flow capability

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The patent employs an open-cell foam core material with interconnected pores that allow fluid to flow through the core while maintaining structural integrity. This porous structure enables the sandwich panel to function as both a structural component and a fluid conduit, resolving the contradiction between strength and fluid flow capability

Inventive Principle:

Principle #31Porous materials

2Adaptability or versatility

If a directionally open core is used to permit fluid flow, then fluid flow capability is improved, but sealing becomes complex and costly

Engineering Contradiction:

Improvefluid flow capabilityVSAvoidsealing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent integrates the sealing function directly into the facesheet structure by forming sealed cavities that enclose portions of the open-cell core. This merging of structural and sealing functions eliminates the need for separate sealing components, reducing complexity while maintaining fluid flow capability through unsealed portions of the core

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If conventional potting compound sealing is applied to an open cellular core, then sealing effectiveness is improved, but manufacturing cost and labor intensity increase

Engineering Contradiction:

Improvesealing effectivenessVSAvoidmanufacturing cost and labor

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces manual potting compound application with a molded facesheet structure that provides sealing through its geometric design. The contoured facesheets form sealed cavities during manufacturing, eliminating the need for labor-intensive sealing operations while maintaining effective sealing of the open-cell core

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If a fully open cellular core is used for omnidirectional fluid flow, then fluid flow versatility is improved, but sealing the periphery becomes impractical

Engineering Contradiction:

Improveomnidirectional fluid flowVSAvoidsealing feasibility

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent segments the open-cell core into multiple sealed cavities enclosed by contoured facesheets, with unsealed portions remaining open for fluid flow. This segmentation allows the structure to maintain omnidirectional fluid flow capability through unsealed areas while providing localized sealed compartments for specific functional requirements

Inventive Principle:

Principle #1Segmentation

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 solution provides a cost-effective and time-efficient method to seal open cellular sandwich structures, preventing fluid ingress and egress, thus protecting the core and maintaining structural integrity while allowing fluid flow, suitable for applications like heat exchangers or fuel tanks.

Implementation Method 1

irradiating a volume of photo-monomer in the reservoir with a series of vertical collimated light beams to form a cured, solid polymer border

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentUS11305509B1Open cellular sandwich structures having sealed edges and methods of manufacturing the same

Publication Date: 2022.04.19 HRL LAB

AI summary

A method of manufacturing a sandwich structure having an open cellular core and a fluid-tight seal surrounding the core includes coupling a mold to a first facesheet to define a reservoir. The method also includes irradiating a volume of photo-monomer in the reservoir with a series of vertical collimated light beams to form a cured, solid polymer border extending around a periphery of the first facesheet. The method also includes irradiating a remaining volume of photo-monomer in the reservoir with a series of collimated light beams to form an ordered three-dimensional polymer microstructure core defined by a plurality of interconnected polymer optical waveguides coupled to the first facesheet and surrounded by the cured, solid polymer border. The method further includes coupling a second facesheet to the ordered three-dimensional microstructure core and the cured, solid polymer border to form the sandwich structure.