Vacuum-Assisted Composite Manufacturing Using Semi-Permeable Membrane
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Solution Overview
Problem
Current manufacturing methods for composite stiffened panels, such as autoclave consolidation, face challenges with complex geometry, porosity, differential thickness, and resin uniformity, especially when using materials with low permeability, leading to quality issues like porosity defects and resin accumulation.
Innovation Solution
A vacuum-assisted process (VAP) with curing tools positioned outside the vacuum bag, utilizing a semi-permeable membrane to manage resin infusion and reduce porosity, where the membrane is gas-permeable but matrix-material-impermeable, allowing better thickness tolerances and resin distribution by adjusting to the preform's geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If curing tools are positioned inside the vacuum bag and inside the semi-permeable membrane, then the process can be simplified, but porosity defects increase and resin distribution becomes non-uniform
Solution Approach 1:
The patent inverts the conventional arrangement by positioning curing tools outside the vacuum bag rather than inside. This inversion allows the semi-permeable membrane to be the only barrier between the tools and preform, improving resin distribution and reducing porosity while maintaining process simplicity through the membrane's selective permeability properties
Solution Approach 2:
The semi-permeable membrane acts as an intermediary element between the curing tools and the preform. It allows gas permeability for vacuum application while blocking matrix material, enabling uniform resin distribution and preventing porosity defects without requiring direct contact between tools and preform
2Ease of manufacture
If curing tools are positioned inside the vacuum bag, then tooling problems are reduced, but resin accumulation occurs at interface lines
Solution Approach 1:
The patent extracts the curing tools from inside the vacuum bag and positions them outside, eliminating the problem of resin accumulation at interface lines. The semi-permeable membrane remains in place to maintain the vacuum seal while allowing uniform resin distribution across the preform surface
Solution Approach 2:
The semi-permeable membrane serves as an intermediary that enables the curing tools to be positioned outside the vacuum bag while still maintaining effective contact with the preform. This resolves the contradiction between tooling ease and thickness uniformity by mediating the interaction between tools and preform
3Strength
If materials with low permeability are used, then structural integrity is improved, but porosity defects increase due to insufficient aeration
Solution Approach 1:
The patent changes the spatial dimension of the aeration surface by positioning curing tools outside the vacuum bag, which increases the effective aeration surface area. This allows sufficient vacuum application and resin infusion even when using low permeability materials, maintaining both structural integrity and low porosity
Solution Approach 2:
The semi-permeable membrane acts as an intermediary that transmits vacuum pressure uniformly across the preform surface, enabling effective resin infusion and air evacuation even through low permeability materials, thus preventing porosity defects while maintaining structural integrity
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 reduces porosity and resin accumulation defects, improves thickness uniformity, and prevents wrinkles in the preform, resulting in higher-quality composite components with complex geometries, such as stiffened panels, using materials like carbon, glass, or hybrid fibers.
Implementation Method 1
providing a semi-permeable membrane which is gas-permeable and matrix-material-impermeable arranged at least around one side of the fibre composite preform
Implementation Method 2
creating vacuum inside the semi-permeable membrane... generating vacuum inside the semi-permeable membrane and the vacuum bag communicating the inside of the semi-permeable membrane with a matrix material reservoir, the material being infused into the preform
Data Source
Figure 1
AI summary
Method for manufacturing fibre composite components, by an infusion method for infusing matrix material, comprising the following steps: - providing a dry fibre composite preform (1, 2) of the component, - providing a semi-permeable membrane (3) which is gas-permeable and matrix-material-impermeable arranged at least around one side of the fibre composite preform (1, 2), - providing curing tools (4) onto the semi-permeable membrane (3), - creating vacuum inside the semi-permeable membrane (3), - removing the curing tools (4), - providing a vacuum bag (5) which is impermeable to gaseous material and matrix material around the semi-permeable membrane (3), - providing the curing tools (4) onto the vacuum bag (5), - generating vacuum inside the semi-permeable membrane (3) and the vacuum bag (5), - communicating the semi-permeable membrane (3) with a matrix material reservoir which is infused, - curing the preform (1, 2), - demoulding the cured preform (1, 2) from the curing tools (4).