Prepreg Tow Steering in Composite Transition Regions
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Solution Overview
Problem
Automated layup of composite structures with high angle transition regions is challenging due to material gathering, wrinkling, and fiber distortion, which limits production efficiency and requires multiple tools and separately fabricated joints.
Innovation Solution
A method involving the use of advanced fiber placement machines to lay prepreg tows in multiple sections with angular orientations less than the bend angle, allowing for the formation of complex geometries as a single component, reducing material gathering and fiber distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wider tows are used to increase material application rate, then productivity is improved, but material gathering and fiber distortion occur in high angle transition regions
Solution Approach 1:
The bend angle is divided into multiple sections, each with a smaller angular orientation than the total bend angle. This segmentation allows wider tows to be placed without excessive steering, preventing material gathering and fiber distortion while maintaining high productivity
Solution Approach 2:
The AFP machine head is dynamically positioned to place each tow section at the correct angular orientation, with the machine head movement coordinated to achieve the desired fiber placement pattern that avoids compression-induced distortion
2Manufacturing precision
If narrower tows are used to reduce material gathering, then fiber distortion is reduced, but productivity decreases and additional reinforcements are needed
Solution Approach 1:
Instead of using narrow tows, the invention uses wider tows placed in multiple sections with different angular orientations. This segmentation approach achieves the same geometric coverage with wider tows, maintaining productivity while avoiding material gathering through reduced steering angles
3Manufacturing precision
If a multi-step process with separately fabricated joints is used to overcome material placement limitations, then manufacturing precision is improved, but device complexity and loss of time increase
Solution Approach 1:
The invention combines the placement of multiple tow sections into a single automated AFP process, eliminating the need for separate fabrication and assembly steps. The numeric controller coordinates the placement of all sections in one continuous operation, reducing device complexity and manufacturing time
Solution Approach 2:
The AFP machine is programmed to perform multiple functions: placing tows at different angular orientations, navigating complex geometries, and creating high angle transition regions all in a single process, eliminating the need for multiple specialized tools
4Ease of operation
If constant radius paths are used for material placement head movement, then ease of operation is improved, but adaptability to complex geometries deteriorates
Solution Approach 1:
The complex geometry is broken down into multiple sections with constant radius paths for each section. The numeric controller sequences these sections to achieve the overall complex geometry, maintaining ease of operation while achieving adaptability through segmented constant radius paths
Solution Approach 2:
The solution adds the dimension of section sequencing to the constant radius path approach. By organizing multiple constant radius paths in a specific sequence with appropriate angular orientations, the system achieves complex geometry formation while maintaining operational simplicity
Data Source
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AI summary
Prepreg tows are placed on a substrate having a bend with a curvature extending over a transition region (28) in the substrate. The tows are steered and laid on the substrate in at least a first section and a second section (42, 44, 46) within the transition region, wherein each of the first and second sections has an angular orientation that is less than the curvature of the bend in order to reduce gathering of the tows.