Sequential Circumferential Deposition of Thermoplastic Composite Prepreg
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Solution Overview
Problem
Processing small diameter composite tubes using thermoplastic resin and fiber prepreg tapes is challenging due to the rigidity of the material and propensity for the tape to split when bent, making it difficult to achieve a smooth circular wrap around a small diameter mandrel without cracking or splitting.
Innovation Solution
A system involving a floating mandrel and sequential heatable folding shoes and forming tubes is used to heat and wrap prepreg tapes, allowing for continuous processing by maintaining the tapes at specific temperatures to soften the thermoplastic resin, facilitating smooth wrapping and layer-by-layer formation of tubular shapes and rods without splitting, with additional consolidation pressure and finishing to ensure a solid, continuous pultrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If prepreg tape is bent around a small diameter mandrel, then the tape can be wrapped to form tubular shapes, but the tape splits or cracks due to its rigidity
Solution Approach 1:
The patent applies thermal parameter changes by heating the prepreg tape to a specific temperature range (100°C to 200°C) before wrapping. This temperature treatment softens the thermoplastic resin, reducing the tape's rigidity and enabling it to bend around small diameter mandrels without splitting or cracking, while maintaining structural integrity during the forming process
2Strength
If multiple layers of prepreg tape are stacked to increase wall thickness, then the strength of the composite tube is improved, but the complexity of the processing system increases
Solution Approach 1:
The patent divides the composite tube formation process into sequential stages, with each stage adding one or more layers of prepreg tape. The system processes tapes layer by layer through a controlled wrapping mechanism, allowing multiple layers to be deposited systematically around the mandrel. This segmentation enables the formation of thick-walled tubes with high strength while managing processing complexity through structured, incremental layer addition
3Ease of manufacture
If the prepreg tape is heated to soften the resin for smooth wrapping, then the wrapping process becomes easier, but the tape becomes more susceptible to deformation
Solution Approach 1:
The patent applies preliminary heating to the prepreg tape before the wrapping operation, bringing the resin to a softened state that facilitates smooth wrapping around the mandrel. This preliminary thermal treatment prepares the tape in advance, allowing it to conform to the desired shape without excessive resistance, while the controlled heating parameters prevent excessive deformation
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 enables the successful continuous processing of small diameter tubes and rods with enhanced strength through wall thickness, preventing splitting and ensuring a smooth, uniform wrap, allowing for the production of composite products with improved properties.
Implementation Method 1
a first heatable folding shoe configured to heat and wrap a first prepreg tape onto the floating mandrel
Implementation Method 2
a first forming tube configured to heat and pultrude the first prepreg tape so as to form a first layer ply of prepreg tape on the floating mandrel
Data Source
AI summary
A system for sequential circumferential deposition of thermoplastic composite prepreg material to layer plies of prepreg tape, allowing the continuous processing of tubular shapes and rods, comprising a floating mandrel; a first heatable folding shoe configured to heat and wrap a first prepreg tape onto the floating mandrel; a first forming tube configured to heat and pultrude the first prepreg tape so as to form a first layer ply of prepreg tape on the floating mandrel; a second heatable folding shoe configured to heat and wrap a second prepreg tape onto the first layer ply of prepreg tape on the floating mandrel; a second forming tube configured to heat and pultrude the second prepreg tape so as to form a second layer ply of prepreg tape over the first layer ply of prepreg tape on the floating mandrel.