Composite Wing Box Manufacturing via Dry Fiber Segmentation
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Solution Overview
Problem
The manufacturing of central aircraft wing boxes using pre-impregnated fiber layers, or 'prepreg', is hindered by the sticky nature of these layers, making automated installation expensive and inefficient, resulting in unsatisfactory production rates.
Innovation Solution
The method involves using dry fiber layers with resin films carried by removable sheets, allowing for easier automated handling, and integrating a pre-polymerization step into the pressing process to ensure efficient impregnation and shaping of U-section crosspieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pre-impregnated fiber layers (prepreg) are used, then the mechanical integrity of composite components is ensured, but the sticky nature of the layers makes automated handling expensive and inefficient
Solution Approach 1:
The process segments the impregnation operation into two distinct phases: first placing dry fiber layers (non-sticky, easy to handle), then separately applying resin films. This segmentation eliminates the stickiness problem during layer placement while ensuring proper impregnation, thereby resolving the contradiction between mechanical integrity and production rate.
Solution Approach 2:
The fiber layers are prepared in advance in a dry, non-sticky state that facilitates easy automated handling. The resin application is deferred to a subsequent step after the layers are positioned, allowing preliminary action on the fiber placement without the complicating factor of resin stickiness, thus improving productivity while maintaining final mechanical integrity.
2Manufacturing precision
If pre-impregnated fiber layers are used, then proper resin impregnation is achieved, but automated handling becomes complicated and costly
Solution Approach 1:
The manufacturing process is segmented into distinct operations: dry layer placement followed by separate resin film application. This segmentation simplifies the automated handling system requirements, as each step deals with non-sticky materials, reducing device complexity while ensuring proper resin impregnation is achieved in the second phase.
Solution Approach 2:
The resin film serves as an intermediary that is applied after the dry fiber layers are positioned. This intermediary approach allows the automated system to first handle only dry, non-sticky fiber layers (simplifying device complexity), then subsequently apply the resin through a controlled film placement process, ensuring proper impregnation without complicating the overall automated system.
3Productivity
If dry fiber layers with separate resin application are used, then automated handling becomes simpler and cheaper, but resin impregnation must be carefully controlled
Solution Approach 1:
The fiber layers are preliminarily positioned in a dry state, establishing the correct architecture before resin application. This preliminary action simplifies automated handling and increases production rate, while the subsequent resin film application step is designed to ensure proper impregnation control by applying resin in a controlled manner after the fiber structure is already in place.
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 approach simplifies the handling and processing of fiber layers, significantly reducing costs and increasing production rates while maintaining the mechanical integrity of the composite material components.
Implementation Method 1
The application of resin films carried by removable sheets simplifies handling by an automated system
Implementation Method 2
a pre-polymerization step of the resin present in the stack of pressed layers
Implementation Method 3
The stack is then polymerized to form the sleeper
Implementation Method 4
a pre-polymerization step of the resin present in the stack of pressed layers
Data Source
Figure 1~3
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Figure 7~10
AI summary
A method for manufacturing a center wing box for an aircraft, comprising a frame formed of U-shaped crossbeams, wherein the formation of at least one crossbeam includes: - a step of building up a stack (34) comprising at least one layer of resin film (28, 33) applied to a layer of dry fibers (24, 29); - a step of pressing this stack (34) to give it a U-shaped cross-section and to compress its layers; and - a step of pre-polymerizing and/or polymerizing the resin of the stack (34). With this solution, the fiber layers handled are dry fiber layers, so their manipulation by an automated machine can be ensured at a reasonable cost and at a high rate. The application of resin films carried by removable sheets (32), i.e., one of whose faces is not sticky, also facilitates manipulation by an automated system.