Rotating Mandrel Vacuum Bag Application for Composite Fuselage Barrels
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Solution Overview
Problem
The application and sealing of vacuum bags for large composite structures, such as fuselage barrels, are inefficient and prone to damage due to manual handling and positioning challenges, leading to logistical difficulties and potential breakages during the polymerization process.
Innovation Solution
A method where the mandrel automatically rotates to draw and wrap a pre-assembled multi-layer vacuum bag material around the fuselage section, ensuring precise positioning and sealing, with operators using a static support structure for ergonomic and safe edge sealing, utilizing a single sheet with adhesive layers for a unified application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual handling methods (bridge cranes, cage elevators) are used to apply the vacuum bag, then the bag can be positioned on the mandrel, but the process is time-consuming and the bag material is at high risk of damage
Solution Approach 1:
The mandrel is designed to rotate automatically about its axis, drawing the bag material from a container and wrapping it around the fuselage barrel surface itself. This self-service mechanism eliminates the need for external cranes and manual positioning, reducing both time and damage risk while maintaining reliable bag application and sealing
Solution Approach 2:
The system transitions from static manual handling to dynamic automated rotation. The mandrel rotates continuously during bag application, enabling the bag material to be drawn and wrapped automatically along the length of the fuselage barrel, significantly improving efficiency and reliability compared to static manual methods
2Ease of operation
If operators manually position and seal the vacuum bag edges, then the bag can be sealed to the mandrel, but operators must work in difficult-to-reach positions which is unsafe and ergonomically poor
Solution Approach 1:
The rotating mandrel system automatically positions the bag material and enables sealing operations to be performed from safe, accessible positions. The rotation brings all sealing locations sequentially to operators working from the side, eliminating the need for operators to lie underneath or reach into hazardous positions while maintaining reliable sealing quality
Solution Approach 2:
Instead of operators moving to reach the sealing positions, the mandrel rotates to bring the sealing positions to the operators. This inversion of the movement paradigm allows operators to work from fixed, safe positions while the workpiece presents all sealing locations sequentially, improving both safety and sealing reliability
3Measurement precision
If the vacuum bag is lowered from above using bridge cranes, then the bag can be positioned on the mandrel, but precise positioning is difficult and the bag material is delicate and prone to damage
Solution Approach 1:
The mandrel rotates automatically to draw the bag material from a container and wrap it around the fuselage barrel with precise, controlled positioning. This self-service rotation eliminates the imprecision and damage risk associated with crane-based lowering, ensuring accurate bag placement and sealing positions throughout the process
Solution Approach 2:
The system replaces static crane positioning with dynamic rotational wrapping. The continuous rotation of the mandrel enables precise, progressive positioning of the bag material as it is drawn and wrapped around the fuselage barrel, achieving accurate positioning without the shocks and imprecisions of crane-based methods
Data Source
Figure 1~2
Figure 3~7
AI summary
A vacuum bag is applied around a fuselage barrel (11) made of composite material to be polymerized, formed by means of lamination on the outer surface of a mandrel (10) having the form of a solid of rotation about a longitudinal axis (x). A bag material in the form of a sheet (30) having a transverse width corresponding to the longitudinal length of the fuselage barrel (11) is provided alongside the mandrel. A first transverse end portion (30a) of the sheet is fastened or sealed on the outer surface of the barrel (11) or the mandrel (10). Then the mandrel is rotated around the axis (x), so as to wrap the sheet (30) about the barrel (11). While the mandrel (10) rotates, the opposite axial end edges (30d) of the sheet (30) are sealed on the mandrel (10). Finally, a second transverse end portion (30b) of the sheet is sealed on the outer surface of the barrel (11) or the mandrel.