Composite Panel Core Structures with Filleted Bonding Transitions
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Solution Overview
Problem
Composite sandwich panels with honeycomb structures have a small surface area for adhesion between the honeycomb core and laminate sheets, leading to a weak bond and reduced shear strength.
Innovation Solution
The introduction of filleted transition regions at the ends of core cells in the honeycomb structure, which increase the surface area for bonding with laminate sheets, and textured or roughened interface surfaces for mechanical locking, enhancing the bond strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a traditional honeycomb core structure is used, then the panel weight is reduced and stiffness is maintained, but the bonding surface area between the core and laminate sheets is small, resulting in weak bond strength
Solution Approach 1:
The patent applies filleted transition regions with curved surfaces at the ends of core cells instead of sharp edges. This curvature increases the bonding surface area and provides a gradual transition that enhances adhesive bonding between the honeycomb core and laminate sheets, directly resolving the contradiction between maintaining lightweight structure and improving bond strength
2Strength
If the honeycomb core has thin end surfaces, then the manufacturing is simpler and material usage is reduced, but the bonding surface area is insufficient leading to weak shear strength
Solution Approach 1:
Filleted transition regions with curved surfaces are introduced at the core cell ends, transforming the simple thin-end structure into a more complex curved geometry that provides increased bonding surface area and improved shear strength while maintaining manufacturing feasibility
3Strength
If adhesive fillets are prepositioned on the honeycomb core, then the bond strength between skin and core is maximized, but the manufacturing process becomes more complex with multiple steps
Solution Approach 1:
The patent prepositions adhesive fillets on the honeycomb core surfaces before final assembly. This preliminary application of adhesive ensures optimal bond strength between the skin and core structures, addressing the contradiction by prioritizing bond strength while accepting increased manufacturing process complexity
Data Source
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AI summary
Core structures for composite panels, aircraft including the same, and related methods. A core structure includes a core body defining a first body side, a second body side, and a plurality of core cells. Each core cell includes at least one cell wall and defines a tubular cell void. Each core cell includes a bulk region and a transition region. Each cell wall is flared within the transition region to increase a surface area of the first body side relative to an average transverse cross-sectional area of the core body. A composite panel includes a core structure with at least one laminate ply coupled to the first body side of a core body. A method of manufacturing a composite panel includes forming a core body via an additive manufacturing process and operatively attaching at least one laminate ply to the core body.