Composite Panel Resin Drainage for Honeycomb Integrity
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Solution Overview
Problem
The manufacturing of composite panels with a honeycomb-type cellular core sandwiched between two skins for acoustic attenuation in turbojet engines faces challenges, particularly with resin infusion methods that result in resin accumulation within the cells, compromising the panel's integrity and acoustic performance.
Innovation Solution
A method involving the integration of drains with specific geometry to facilitate resin impregnation and drainage during the manufacturing process, allowing for a single-step formation of a composite panel with a cellular core interposed between two structural plies, thereby avoiding the need for gluing and ensuring cell integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If resin infusion technique is used to manufacture composite panels, then the panel can be formed with two aerodynamic faces, but resin accumulates inside the cells compromising integrity and acoustic performance
Solution Approach 1:
The patent divides the resin infusion process into controlled zones by introducing drains that segment the resin flow path. The drains create separate channels that allow resin to be introduced and distributed without accumulating in the cellular core, enabling precise control over resin placement while maintaining cell integrity.
Solution Approach 2:
The patent introduces drains as intermediary elements between the resin injection system and the cellular core. These drains act as mediators that control resin flow, allowing resin to impregnate the structural plies while preventing it from penetrating into and sealing the honeycomb cells, thus preserving acoustic performance.
2Strength
If multiple separate parts are manufactured and glued to form sandwich composite structure, then the panel can achieve required structural configuration, but the manufacturing process becomes complex and time-consuming
Solution Approach 1:
The patent merges the manufacturing of multiple separate parts into a single integrated process. By using a mold that accommodates the cellular core and structural plies simultaneously, and by using drains that enable complete resin infusion in one operation, the process combines what would traditionally require multiple separate manufacturing and assembly steps into one unified operation.
Solution Approach 2:
The patent performs preliminary positioning of the cellular core and structural plies within the mold before resin infusion. The drains are pre-configured in their final positions, and all components are arranged in their final configuration before the resin is introduced, eliminating the need for subsequent assembly operations.
3Manufacturing precision
If RTM method is used to obtain parts with two perfectly calibrated smooth faces, then surface quality is improved, but resin presence inside cells is undesirable for acoustic attenuation
Solution Approach 1:
The patent applies local quality control by using drains with specific geometry configured to provide draining only in specific locations and directions. The drains are positioned to allow resin to flow freely in certain areas while preventing resin penetration into the cellular core structures, enabling different resin distribution characteristics in different regions of the composite panel.
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 simplifies the manufacturing process, reduces energy consumption, minimizes environmental impact, and maintains the structural and acoustic performance of the composite panel by preventing resin from sealing the cells, while reducing the number of manufacturing steps and ensuring consistent surface quality.
Implementation Method 1
carrying out a draining of the resin through the drains in the element with a cellular structure during the infusion step
Implementation Method 2
infusion of the element with a cellular structure so as to impregnate it with a resin
Implementation Method 3
polymerization of the impregnated element with a cellular structure to form the composite panel
Data Source
AI summary
The present disclosure concerns a method for manufacturing a composite panel including a cellular central core interposed between two skins. The manufacturing method includes the steps of manufacture of an element with a cellular structure comprising a cellular core structure interposed between two layers of structural plies intended to form the skins, positioning of the element with a cellular structure within a mold, formation of drains on either side of the cellular core structure, infusion of the element with a cellular structure so as to impregnate it with a resin, carrying out a draining of the resin through the drains in the element with a cellular structure during the infusion step, the drains having a geometry configured to provide draining, and polymerization of the impregnated element with a cellular structure to form the composite panel.