Honeycomb Panel Fastening with Pyramidal Core Reinforcement
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Solution Overview
Problem
Attaching structures or hardware to honeycomb sandwich core materials using load-bearing fasteners is challenging and expensive due to the inherent limitations of the honeycomb geometry and strength, requiring complex configurations and modifications to the panel.
Innovation Solution
A tetrahedral-octahedral honeycomb lattice core with pre-formed pyramidal shapes and a hardening filler material is used to create a geometrically supportive framework for fasteners, enhancing connective strength and stability by bonding the fastener and filler into a sturdy core space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional honeycomb sandwich core materials are used with load-bearing fasteners, then the fastening system can attach structures to panels, but the strength is inherently limited to skin strength and requires complex configurations including cutting sections and drilling at angles
Solution Approach 1:
The patent applies preliminary action by pre-forming pyramidal shapes within the honeycomb core cells before fastener installation. These pyramidal fillers are inserted into the core cells and bonded with filler material to create pre-strengthened attachment points. When fasteners are subsequently installed, they engage with these pre-formed pyramidal structures rather than relying solely on the thin skin strength, thereby achieving higher fastener strength without complex drilling or cutting operations.
2Strength
If honeycomb core cells are filled with epoxy or other filler materials to strengthen fastener attachment, then attachment strength can be improved, but the strength is limited because of the thinness of the honeycomb walls
Solution Approach 1:
The patent applies local quality by placing pyramidal fillers only in specific core cells where fastener attachment is required, rather than filling the entire honeycomb structure. The pyramidal shapes are strategically positioned to provide localized strengthening at attachment points. This approach concentrates the filler material where it is most needed, achieving high attachment strength while minimizing the amount of filler material and reducing overall structural complexity.
3Ease of operation
If sections of the honeycomb panel are cut out and holes are drilled at an angle to provide support for fillers, then fastener attachment can be achieved, but the process becomes expensive and complex
Solution Approach 1:
The patent applies preliminary action by pre-assembling the pyramidal fillers with fasteners before installation into the honeycomb core. The pyramidal shapes are inserted into the core cells and bonded with filler material in advance, creating pre-strengthened attachment points. This eliminates the need for complex on-site operations such as cutting honeycomb sections or drilling angled holes, thereby simplifying both manufacturing and installation processes.
4Reliability
If insert assemblies with high specific strength are used to reduce stress concentrations, then stress distribution can be improved, but the configuration becomes complex with four functional components including insert, potting material, upper face plate and lower face plate
Solution Approach 1:
The patent applies merging by combining the filler material and pyramidal support structure into a single integrated component. The pyramidal fillers are inserted into the core cells and bonded with filler material that becomes part of the pyramidal structure itself, creating a unified load-bearing element. This eliminates the need for separate inserts, potting material, face plates, and other components, thereby reducing the number of parts from four functional components to a single integrated pyramidal filler assembly while maintaining stress concentration reduction and improving reliability.
Data Source
AI summary
A system, comprising a panel comprising a tetrahedral-octahedral honeycomb lattice, a skin layer formed on a first side of the lattice, having an aperture formed therein configured to receive a fastener, and a fastening assembly comprising a fastener configured to be mounted to the panel when the panel is fixed to an adjacent component, and a hardening material. Corresponding systems and methods also are disclosed.