Honeycomb Core Crush Prevention via Localized Filler
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Solution Overview
Problem
The pressurization during the cure cycle of honeycomb composite structures often causes movement and crushing of the honeycomb core elements, leading to structural defects and scrapage due to the core cells closing, resulting in unintended composite structures.
Innovation Solution
A core assembly with a layer of filler material is used, which is applied at the face of the core component to partially fill selected cells, rigidizing upon curing and preventing movement and crushing under pressure, allowing for a lighter weight core and reduced laminate thickness while maintaining crush resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pressure is applied during the cure cycle to bond laminates to the honeycomb core, then the laminates are properly bonded to the core, but the honeycomb core elements move and crush, causing structural defects
Solution Approach 1:
The patent applies filler material to specific high-risk areas of the honeycomb core (edges and corners) rather than uniformly filling all cells. This localized application prevents core movement and crushing at critical locations while maintaining the overall honeycomb structure's lightweight properties and allowing proper laminate bonding under cure cycle pressure.
Solution Approach 2:
The patent uses a composite approach by combining the honeycomb core material with a filler material (such as epoxy, polyurethane, or polysulfone) that has different mechanical properties. The filler material provides the necessary rigidity and support to prevent core deformation under pressure, while the honeycomb structure maintains its weight-saving characteristics.
2Weight of moving object
If the honeycomb core is left empty to maintain lightweight structure, then weight is reduced, but the core crushes and cells close under cure cycle pressure
Solution Approach 1:
Instead of uniformly filling the entire honeycomb core which would add significant weight, the patent selectively fills only certain cells or portions of cells (particularly edges and corners) with filler material. This localized filling provides crush resistance where it is most needed while preserving the lightweight characteristics of the overall core structure.
Solution Approach 2:
The patent applies partial filling of the honeycomb cells rather than complete filling. The filler material is applied to a depth that provides sufficient support to prevent crushing under cure pressure, but does not over-fill the cells, thereby minimizing added weight while achieving the necessary structural support.
3Stability of the object's composition
If filler material is applied to rigidize the core and prevent crushing, then core stability is improved, but manufacturing complexity increases
Solution Approach 1:
The filler material is applied to the honeycomb core before the laminate bonding process. This preliminary application of filler material prepares the core in advance to withstand the pressures of the cure cycle, eliminating the need for additional support structures or complex process modifications during the bonding operation itself.
Solution Approach 2:
The patent utilizes filler materials that change their physical properties during curing - transitioning from a liquid or semi-liquid state during application to a solid rigid state during curing. This parameter change allows the filler to be easily applied in liquid form (simplifying the application process) and then provides rigid support when cured, preventing core deformation without requiring complex manufacturing equipment.
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 filler material effectively prevents core component movement and crushing during the cure cycle, enabling the production of composite structures with intended design specifications and improved structural integrity.
Implementation Method 1
the filler material rigidizes when cured to prevent movement and/or crushing of core component under a pressure applied during a cure cycle
Data Source
AI summary
A composite structure includes a first laminate and a second laminate. At least one core assembly is located between the first laminate and the second laminate. The at least one core assembly includes a core component and a layer of filler material disposed at a first face of the core component. The layer of filler material at least partially fills selected cells of the core component to a fill depth such that the filler material rigidizes when cured to prevent movement and/or crushing of core component under a pressure applied during a cure cycle of the composite structure.