In-situ Multi-stage Debulk and Compaction of Thick Composite Repair Laminates
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Solution Overview
Problem
Conventional methods for repairing polymeric-matrix composite parts are costly and impractical due to the need for specialized tooling and processes like double vacuum tooling and autoclave processing, which are expensive and inefficient for in-situ repairs.
Innovation Solution
A method for in-situ, multi-stage debulking, compaction, and single-stage curing of thick composite repair laminates using a sealing bag with vacuum and heat to achieve laminate quality comparable to autoclave processing, involving debulking and compaction at lower temperatures followed by curing at higher temperatures under vacuum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional double vacuum tooling and autoclave processing are used, then laminate quality is improved, but device complexity and cost increase
Solution Approach 1:
The curing process is divided into multiple stages with different vacuum levels. The method uses multi-stage debulking followed by compaction and final curing, where each stage operates at optimized vacuum conditions rather than requiring constant high vacuum throughout the entire process. This segmentation allows achieving high laminate quality without needing complex autoclave equipment.
Solution Approach 2:
The method performs preliminary debulking and compaction actions before final curing. By removing excess resin and consolidating plies in advance through controlled vacuum stages, the process prepares the laminate structure to achieve high quality during the subsequent curing stage without requiring autoclave-level pressure and temperature control throughout the entire process.
2Manufacturing precision
If multi-stage debulking and compaction is performed before curing, then laminate quality is improved, but process time increases
Solution Approach 1:
The debulking, compaction, and curing operations are performed continuously in sequence without removing the laminate from the mold or resetting the tooling. The vacuum bag remains in place throughout all stages, and the laminate progresses continuously from debulking through compaction to final curing, minimizing non-productive time and setup operations.
3Productivity
If thick laminates are cured in a single stage, then productivity is improved, but manufacturing precision may deteriorate
Solution Approach 1:
The single-stage curing process is actually segmented into multiple vacuum stages (debulking, compaction, and curing stages) with different vacuum levels and hold times. This internal segmentation within the single curing operation allows thick laminates to be properly processed while maintaining productivity, as each stage is optimized for its specific function rather than using multiple separate curing cycles.
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 cost-effective and practical repair of polymeric-matrix composite parts by achieving high-quality laminate repairs without the need for expensive autoclave processing, reducing the complexity and cost of the repair process while maintaining laminate quality.
Implementation Method 1
a) applying a vacuum to the uncured plies to debulk and partially compact the uncured plies
Implementation Method 2
b) heating the uncured plies to a temperature sufficient to debulk and partially compact the uncured plies
Implementation Method 3
c) irradiating the uncured plies with a high energy source to cure the resin
Data Source
AI summary
A method for fabricating a repair laminate for a composite part having an exposed surface includes applying a bonding material to the exposed surface and forming an uncured ply stack assembly on the bonding material. The uncured ply stack assembly is formed by forming and compacting a series of uncured ply stacks. The ply stack assembly and bonding material are then cured.