Slotted Composite Repair Stack for Curved Geometry Restoration
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Solution Overview
Problem
The repair of damaged composite structures, particularly those with curved geometries, is time-consuming and expensive due to the difficulty in replicating the original geometry and stiffness, especially in aerospace applications like aircraft components, where carbon fiber-reinforced plastic materials are used.
Innovation Solution
A method involving a composite stack assembly with slotted books and an adhesive, cured under vacuum pressure to create a repair piece that matches the damaged area's geometry, restoring structural integrity without the need for complex tooling or autoclaving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing repair processes are used to repair damaged composite members with curved geometries, then the original geometry and stiffness can be restored, but the repair process becomes time-consuming and expensive
Solution Approach 1:
The repair method segments the composite structure into the damaged portion and the undamaged portions. The damaged portion is removed and replaced with a new composite portion that is manufactured separately and then attached to the undamaged portions, avoiding the need to repair the entire structure in place.
Solution Approach 2:
The new composite portion is manufactured in advance using pre-impregnated materials before the repair process. This preliminary manufacturing allows the repair to proceed more quickly by simply attaching the pre-fabricated portion to the undamaged sections.
2Manufacturing precision
If tooling surfaces are created to match complex geometries, then accurate geometry restoration is achieved, but the device complexity and cost increase
Solution Approach 1:
The new composite portion is designed to replicate or copy the geometry of the original damaged portion. By using pre-impregnated materials and standard manufacturing techniques, a accurate copy can be produced without requiring complex custom tooling surfaces.
Solution Approach 2:
The invention changes the manufacturing parameters from requiring complex tooling surfaces to using pre-impregnated materials that can be cured in simpler fixtures. This parameter change maintains geometry accuracy while reducing tooling complexity.
3Manufacturing precision
If autoclaving is used to cure pre-impregnated materials, then high quality composite parts are produced, but the process time and energy consumption increase
Solution Approach 1:
The invention uses disposable pre-impregnated composite materials that are designed for single-use. These materials contain pre-applied resin that cures quickly without requiring expensive and time-consuming autoclaving processes, maintaining adequate quality for repair applications.
Solution Approach 2:
The curing parameters are changed from high-temperature autoclaving to lower-temperature or room-temperature curing of pre-impregnated materials. This parameter change reduces both time and energy requirements while producing sufficient material quality for structural repair.
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 allows for efficient and cost-effective repair of composite members with complex geometries by producing a repair piece with comparable material and mechanical properties to the original, reducing downtime and maintenance costs in aerospace and other industries.
Implementation Method 1
An adhesive is disposed between the first book and the second book
Data Source
AI summary
A method for repairing a composite member includes assembling a composite stack on a surface. The composite stack includes a first book nested with a second book. An adhesive is disposed between the first book and the second book. At least one of the first book and the second book includes a first pattern of slots. The method further includes setting the composite stack to yield a composite repair piece. The method further includes attaching the composite repair piece to the composite member. Also disclosed is a composite repair piece. The composite repair piece includes a first book and a second book. The second book is stacked on top of the first book. An adhesive is disposed between the first book and the second book. At least one of the first book and the second book includes a first pattern of slots.