Bridging Fibers in Foam Core Composite Panels
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Solution Overview
Problem
Composite panels with lightweight foam cores and fiber-reinforced skins face limitations in mechanical properties due to delamination and core fracture, particularly under bending forces, necessitating improved compatibility and bridging mechanisms between skins and core.
Innovation Solution
The method involves depositing bridging fibers on the core's surface, which penetrate partially or completely through the core to form composite bridges between the skins, enhancing mechanical resistance and delamination resistance by optimizing fiber type, length, and orientation, and using a device for precise needling and resin migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fibers from the skins are used to bridge between skins, then delamination resistance is improved, but the mechanical properties and resin migration capability are insufficient
Solution Approach 1:
The patent divides the fiber system into two distinct components: skin fibers for structural purposes and dedicated bridging fibers for resin migration and delamination resistance. This segmentation allows each fiber type to be optimized for its specific function, resolving the contradiction between mechanical strength and delamination resistance.
Solution Approach 2:
The patent introduces dedicated bridging fibers as intermediary elements between the skins that are specifically designed to facilitate resin migration. These bridging fibers act as mediators that enhance delamination resistance without compromising the mechanical properties of the skin fibers.
2Reliability
If needling is used to insert fibers through the core, then skin-core connection is improved, but the process becomes unsuitable when skin thickness or density varies
Solution Approach 1:
The patent applies preliminary needling to the core before skin deposition to create channels for bridging fibers. This preliminary action prepares the core structure in advance, making it adaptable to subsequent variations in skin thickness and density without requiring adjustment of the needling process itself.
Solution Approach 2:
The patent changes the parameters of the bridging fibers (length, diameter, orientation) independently of the skin parameters. This allows the bridging system to adapt to varying skin thickness and density while maintaining effective skin-core connection.
3Productivity
If high-speed production is implemented, then productivity is improved, but resin migration capability must be enhanced to maintain quality
Solution Approach 1:
The patent designs bridging fibers with self-service characteristics where the fiber structure itself facilitates resin migration through capillary action and surface properties. This self-service mechanism ensures adequate resin migration even at high production speeds without requiring additional process control.
Solution Approach 2:
The patent uses composite material principles by combining different fiber types (skin fibers and bridging fibers) with distinct properties. The bridging fibers are specifically engineered with material properties that enhance resin migration capability, allowing high-speed production while maintaining quality.
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 approach significantly enhances the mechanical performance of composite panels by improving delamination resistance and allowing for high-speed production with flexible combinations of fibers, reducing material waste and costs, while ensuring precise control over fiber placement and density.
Implementation Method 1
the resin can migrate along the partially or totally traversing fibers and thus form bridges between the two skins
Implementation Method 2
These fibers are deposited on the surface without any connecting element... These fibers are deposited on the face in a quantity at least equal to the bridging requirements... bridging fibers 12 to penetrate, through or partially through the core
Data Source
Figure 1A~1D
Figure 2A~2B
Figure 3
AI summary
The invention relates to a method for making a core (10), having built-in cross-linking fibers (12), for manufacturing composite panels, said method being characterized in that it consists of carrying out the following steps: gaining access to a bar made of a light rigid foam material that forms the core (10); depositing an excess of cross-linking fibers (12) onto at least one surface (18, 20) of the core; feeding a portion of said cross-linking fibers (12) into the core; and removing the unused excess of cross-linking fibers. The invention also relates to the resulting panel, as well as to the related device.