Curved Composite Parts Manufacturing Without Wrinkles
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Solution Overview
Problem
Conventional manufacturing processes for curved composite parts in aircraft structures often result in wrinkles, which compromise load transfer efficiency and require the introduction of unwanted 'mouseholes' to mitigate wrinkling, affecting structural integrity and maintenance accessibility.
Innovation Solution
A method for manufacturing curved composite parts that involves laying up flat preforms with strategically introduced discontinuities, allowing for continuous surfaces without 'mouseholes' by using Automated Tape Laying or Automated Fibre Placement technologies, and forming these parts to achieve desired curvatures without wrinkles, ensuring effective load transfer and structural stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional pre-forming processes are used to create curved composite parts, then the parts can achieve desired curvature, but wrinkles appear on the compression side compromising load transfer
Solution Approach 1:
The patent introduces discontinuities in the ply arrangement before the pre-forming process, specifically placing gaps or offsets in the fiber layers that will become the outer cap. This preliminary action allows the plies to accommodate curvature without compression-induced wrinkling, as the discontinuities provide space for the compressed material to relocate into during forming.
Solution Approach 2:
The patent segments the composite structure by introducing discontinuities that divide the continuous ply into separate sections. These segmented plies are arranged such that the discontinuities are positioned to allow relative movement between ply sections during pre-forming, enabling the outer cap to form without wrinkles while maintaining structural integrity.
2Manufacturing precision
If mouseholes are introduced to mitigate wrinkling, then wrinkles are avoided, but structural integrity and maintenance accessibility are compromised
Solution Approach 1:
The patent extracts the harmful wrinkling effect by introducing controlled discontinuities that eliminate the root cause of wrinkles (compression of continuous plies) without requiring mouseholes. The discontinuities are strategically placed to provide relief space for compressed material, achieving wrinkle-free surfaces while maintaining continuous load paths and structural integrity.
3Strength
If continuous plies are used without discontinuities, then load transfer is effective, but wrinkles appear during pre-forming
Solution Approach 1:
The patent applies local quality by introducing discontinuities only in specific regions where they are most beneficial - in the plies that will form the outer cap of the curved structure. The discontinuities are positioned locally to accommodate compression during pre-forming, while other regions maintain continuous plies for effective load transfer. This localized modification achieves wrinkle-free surfaces without compromising overall structural strength.
Data Source
Figure 1a~1b
Figure 2a
Figure 2b
AI summary
The present invention provides a method for manufacturing curved composite parts, or a portion thereof, by an automated process and suitable for being integrated in structures, such as frames, beams, spars or ribs with any radius of curvature, and with the proviso that no mouseholes shall be present in the final manufactured curved composite part.