Ply Splicing for Composite Charges Spanning Contours
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Solution Overview
Problem
The forming process of composite parts often results in shape discrepancies due to ply slippage during the shaping of composite charges, leading to out-of-tolerance issues and potential discarding of composite charges.
Innovation Solution
Incorporating splice zones within the composite charges, where ply segments are subdivided and spliced to accommodate slippage, allowing for controlled shaping without excessive wrinkles, thereby reducing the likelihood of discrepancies and enhancing the efficiency of the layup process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If plies are pressed by mandrel and die to achieve desired contour, then the composite charge achieves the desired shape, but ply slippage occurs resulting in shape discrepancies (wrinkles)
Solution Approach 1:
The patent divides continuous plies into discrete ply segments with splice zones between them. This segmentation allows controlled relative movement between segments during forming, preventing the accumulation of slippage that would otherwise cause wrinkles and shape discrepancies in continuous plies.
Solution Approach 2:
The patent introduces splice zones with specific local properties (overlap regions, reduced fiber continuity) at strategic locations within the composite charge. These localized zones act as slip planes that accommodate deformation during forming, while the remaining portions of the plies maintain their structural integrity and fiber continuity.
2Strength
If plies are made continuous to maintain fiber strength, then structural integrity is improved, but ply slippage during forming increases causing out-of-tolerance discrepancies
Solution Approach 1:
The patent segments continuous plies into multiple ply segments connected by splice zones. This maintains fiber continuity within each segment for structural strength, while the splice zones provide controlled slip planes that prevent excessive slippage and shape discrepancies during the forming process.
Solution Approach 2:
The patent changes the physical parameters of the ply structure by introducing overlap regions in splice zones where fibers are discontinuous or have reduced bonding. This parameter change allows controlled slippage in specific locations while maintaining overall fiber continuity and strength in the composite charge.
3Ease of manufacture
If splice zones are introduced to accommodate slippage, then shaping process is facilitated and discrepancies reduced, but device complexity increases due to additional splicing operations
Solution Approach 1:
The patent performs splicing operations during the layup phase before the forming process. Ply segments are pre-positioned and bonded in splice zones while the composite charge is still in a manageable flat or partially formed state, making the splicing operation easier and more accessible than attempting to splice during or after high-pressure forming.
Solution Approach 2:
The patent uses resin matrices and overlap regions as intermediary bonding elements in splice zones. These intermediaries facilitate the connection between ply segments while allowing controlled relative movement, simplifying the splicing operation compared to direct fiber-to-fiber bonding and enabling easier accommodation of slippage during forming.
4Device complexity
If traditional laying up method is used without splicing, then fabrication process is simpler, but layup speed is reduced due to reshaping or discarding out-of-tolerance composite charges
Solution Approach 1:
The patent incorporates splice zones during the initial layup process, performing the splicing action beforehand. This preliminary action prevents the formation of out-of-tolerance composite charges that would require costly and time-consuming reshaping or discarding, thereby maintaining simple fabrication processes while significantly improving productivity.
Data Source
AI summary
Systems and methods are provided for designing composite parts. One embodiment is a method for fabricating a composite part. The method includes receiving a design that defines a stacking sequence for a composite charge comprising plies that have different fiber orientations, defining a splice zone within the design, modifying the design by splicing plies in a manner that accommodates ply slippage when the composite charge is formed to a contour, and fabricating a composite part based on the design that was modified.