Flexible Compactor for Composite Stiffener Wrinkle Control
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Solution Overview
Problem
The fabrication of contoured composite stiffeners, such as stringers, faces challenges with unpredictable ply wrinkling and gathering due to complex geometries, leading to inconsistencies in the finished parts and difficulties in controlling these issues during hand layup processes.
Innovation Solution
A flexible compactor device capable of conforming to multiple planes is developed, featuring sections with reinforcement strips and flexible rubber joints, allowing it to conform to complex geometries and regulate ply wrinkling and gathering, while a vacuum system ensures consistent adhesion and distribution during transportation and compaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hand layup techniques are used to compact contoured composite stringers, then flexibility in handling complex geometries is improved, but manufacturing precision deteriorates due to unpredictable ply wrinkling and gathering
Solution Approach 1:
The compactor is constructed with flexible materials including rubber layers and fabric-reinforced rubber that allow it to conform to compound curved surfaces of composite stringers. The flexible construction enables the compactor to adapt to complex geometries while maintaining consistent contact pressure across the contoured surface, thereby predicting and controlling ply wrinkling and gathering locations.
Solution Approach 2:
The compactor is divided into multiple sections that can independently flex and conform to different portions of the contoured stringer. This segmentation allows each section to adapt to local geometry variations while the overall structure maintains controlled distribution of wrinkles and gathering through engineered flexure patterns.
2Ease of manufacture
If compactors flexible in a single plane are used, then ease of manufacture is improved, but adaptability deteriorates when stringers are contoured in more than one plane
Solution Approach 1:
The compactor utilizes composite construction combining rubber layers with fabric reinforcement. This composite material approach provides both flexibility in multiple planes and structural integrity, allowing the compactor to conform to compound curvatures while maintaining ease of manufacture through layered material assembly rather than complex monolithic structures.
Solution Approach 2:
The compactor design incorporates flexibility in multiple planes by stacking flexible layers that can deflect in different directions. This multi-dimensional flexibility is achieved through the layered composite structure that allows independent flexure in each layer, enabling conformity to three-dimensional contoured surfaces.
3Productivity
If automated compaction processes are implemented, then productivity is improved, but device complexity increases due to the need for multi-plane flexibility and vacuum systems
Solution Approach 1:
The compactor incorporates a vacuum system that uses pneumatic principles to adhere the composite stringer to the compactor surface and maintain contact during transport and compaction. The vacuum distribution system provides automated control of adhesion forces, enabling productive automation while managing device complexity through standardized pneumatic components.
Solution Approach 2:
The flexible compactor structure is designed to automatically conform to the stringer geometry through its inherent material properties and structural design. The self-adjusting nature of the flexible composite construction reduces the need for complex active control mechanisms, allowing automated operation with relatively simple device architecture.
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 predictable and consistent distribution of ply wrinkling and gathering, improving part quality and performance by allowing for engineering changes to compensate for these issues, thereby enhancing the precision and reliability of composite stiffener fabrication.
Implementation Method 1
Adhering the stiffener layup to the compactor includes generating a vacuum inside the compactor, and using the vacuum to suck the stiffener layup against the compactor
Implementation Method 2
The cap portion also includes a plurality of flexible rubber joints along its length which allow the second section to flex within the second plane
Implementation Method 3
The stiffener layup is compacted against the surface by the compactor
Data Source
AI summary
A device for compacting a contoured elongate composite layup includes flexible first and second fiber reinforced resin flexible sections flexible along their lengths. The first section is flexible within a first plane and the second section is flexible within the first plane as well as within a second plane.