CFRP Sandwich Structure Weight Reduction via Direct Resin Bonding
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Solution Overview
Problem
Existing sandwich structures used in small aircraft, such as air mobility vehicles, have a high weight due to the thickness of the fiber-reinforced plastic (FRP) layers, which hinders further weight reduction.
Innovation Solution
A sandwich structure comprising at least one first ply and one second ply of carbon fiber reinforced plastic (CFRP) with a honeycomb or foam core, where the CFRP plies have a thickness of 0.05 mm to 0.15 mm and the thermoset resin acts as an adhesive directly bonded to the core without interposing any other layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of FRP layers is increased to maintain mechanical strength, then the strength is improved, but the weight increases
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness of FRP layers to a specific range (0.05-0.15mm) and controlling the resin content (30-70 mass%) to achieve the optimal balance between mechanical strength and weight reduction. This quantitative parameter optimization allows the structure to maintain sufficient strength while minimizing weight.
Solution Approach 2:
The patent uses composite materials by combining carbon fiber reinforced plastic (CFRP) with a honeycomb core structure. The CFRP layers are bonded directly to the honeycomb core using thermoset resin, creating a composite sandwich structure that achieves high strength-to-weight ratio by leveraging the strength of both the fiber-reinforced plastic and the lightweight core.
2Reliability
If adhesive layers are added to bond FRP to core, then the bonding reliability is improved, but the weight increases
Solution Approach 1:
The patent extracts and eliminates the separate adhesive layer from the bonding system. Instead of using a dedicated adhesive layer between the FRP and honeycomb core, the thermoset resin within the FRP itself is used for bonding, thereby removing the unnecessary intermediate layer and reducing weight while maintaining bonding reliability.
Solution Approach 2:
The thermoset resin in the FRP serves dual functions: as the matrix material providing structural integrity and as the adhesive bonding the FRP to the honeycomb core. This multi-functionality eliminates the need for separate adhesive layers, reducing weight while maintaining reliable bonding.
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 configuration achieves a significant weight reduction of the sandwich structure while maintaining sufficient mechanical properties, making it suitable for use in small aircraft as a structural material.
Implementation Method 1
The first thermoset resin is directly bonded to the core without interposing any other layer between the first thermoset resin and the core. The second thermoset resin is directly bonded to the core without interposing any other layer between the second thermoset resin and the core.
Implementation Method 2
heating and curing first uncured thermoset resin with the first uncured thermoset resin in direct contact with one side of the core so that the first cured thermoset resin is directly bonded to the one side of the core
Data Source
AI summary
A sandwich structure includes a first ply of CFRP, a second ply of CFRP and a honeycomb or foam core. The first ply of the CFRP includes first carbon fibers and thermoset resin which is matrix reinforced with the first carbon fibers. The second ply of the CFRP includes second carbon fibers and thermoset resin which is matrix reinforced with the second carbon fibers. The core is sandwiched between the first and second plies of the CFRP. Ply thicknesses of the first and second plies of the CFRP are each not less than 0.05 mm and not more than 0.15 mm. The first thermoset resin is directly bonded to the core without interposing any other layer between the first thermoset resin and the core. The second thermoset resin is directly bonded to the core without interposing any other layer between the second thermoset resin and the core.