Slit Unidirectional Composite Tapes for Low-Bulk Molding
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Solution Overview
Problem
Current methods for producing composite fabrics using low-pressure molding processes result in inconsistencies, such as undesired bulk and fiber dislocations, when interlayer materials are introduced between plies, leading to gaps and excess weight in composite components.
Innovation Solution
A method and apparatus involving the formation of unidirectional composite tapes with porous bonding layers, which are slit and laid down at predetermined angles to form a composite fabric, allowing for controlled fiber configuration and reduced bulk, and the use of a conveyor bed and tape lay-down units to create layers with improved flexibility and infusion performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If interlayer materials are introduced between plies during low-pressure molding, then flexibility and resin infusion are improved, but bulk and fiber dislocations occur causing gaps and excess weight
Solution Approach 1:
The interlayer material is segmented into discrete positioning members distributed between plies rather than continuous layers, allowing localized flexibility without causing widespread fiber dislocation or bulk
Solution Approach 2:
The positioning members provide localized flexibility and resin infusion pathways only where needed, while maintaining fiber alignment and low bulk in the surrounding areas of the composite fabric
2Ease of manufacture
If traditional knitting machines are used to create composite fabrics, then fabric structure is formed, but bulk and fiber spreading inconsistencies occur
Solution Approach 1:
Fibers are pre-aligned and pre-spaced on the conveyor bed before consolidation, ensuring uniform fiber spacing and configuration is established before the knitting or bonding process begins
Solution Approach 2:
The traditional mechanical knitting machine system is replaced with a conveyor bed system that uses controlled placement and preliminary alignment mechanisms to achieve more consistent fiber spacing and configuration
3Reliability
If autoclave processing is used for large composite parts, then curing is achieved, but equipment size and cost increase
Solution Approach 1:
The curing process parameters are changed from high-pressure autoclave conditions to low-pressure or atmospheric pressure conditions, allowing large parts to be cured without requiring large autoclave equipment
Solution Approach 2:
The composite fabric is designed with localized properties (low bulk, controlled porosity in specific areas) that enable selective resin infusion and curing without requiring uniform high-pressure treatment across the entire large part
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
The solution enables the production of composite fabrics with reduced bulk and improved fiber alignment, flexibility, and resin infusion, allowing for the creation of composite components with desired thickness and quality without the need for large autoclaves, thus reducing production costs and complexity.
Implementation Method 1
The unidirectional lay-up of fibers is heated under pressure to form a unidirectional composite tape to substantially maintain the fibers in a desired configuration
Implementation Method 2
The unidirectional lay-up of fibers is heated under pressure to form a unidirectional composite tape
Implementation Method 3
A first porous bonding layer is formed... At least one of the first plurality of lengths of the unidirectional composite tape and the second plurality of lengths of the unidirectional composite tape is slit while laying down... to improve infusion performance
Data Source
AI summary
A method and apparatus for manufacturing. A fiber layer and a first porous bonding layer are formed to form a unidirectional lay-up of fibers. The unidirectional lay-up of fibers is heated under pressure to form a unidirectional composite tape. A first plurality of lengths of the unidirectional composite tape is laid down to build a first layer from the unidirectional composite tape. A second plurality of lengths of the unidirectional composite tape is laid down to build a second layer from the unidirectional composite tape on the first layer at a predetermined angle from the first layer. At least one of the first and second plurality of lengths of the unidirectional composite tape are slit while laying down the first and second plurality of lengths of the unidirectional composite tape. A composite fabric is formed from the first and second layer.