Composite Flange Forming Tension Control
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Solution Overview
Problem
The existing methods for manufacturing composite structures with integral curved flanges, such as containment cases for gas turbine engines, face challenges in achieving consistent quality and preventing distortion during the forming process, often resulting in heavier flanges due to excess material and manual lay-up techniques.
Innovation Solution
A method involving a preform with a distal and proximal portion, where the second bend balances the first bend to keep uni-directional ply material in tension, preventing wrinkling or buckling, and using oblique-angle tapes to maximize the benefit, along with a vacuum bag membrane for clamping and a two-stage temperature process for curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual lay-up techniques are used for the flange, then the plies can be positioned to follow the contour of the housing, but the quality becomes inconsistent and excess material is required
Solution Approach 1:
The composite structure is divided into two parts: a main body formed by machine lay-up and a flange formed by manual lay-up. This segmentation allows each part to be optimized for its specific manufacturing requirements, with the flange being manually formed to achieve consistent quality without requiring machine automation.
Solution Approach 2:
Different manufacturing approaches are applied to different parts of the structure. The main body uses automated machine lay-up for efficiency, while the flange uses manual lay-up for precision and quality consistency. This local quality approach allows each region to be manufactured with the most appropriate technique.
2Ease of manufacture
If the preform is formed without a distal portion, then the forming process is simpler, but distortion and wrinkling occur during bending
Solution Approach 1:
A distal portion is added to the preform before the forming process. This preliminary action of extending the plies beyond the initial contour creates tension that prevents wrinkling and distortion during the subsequent bending operation, ensuring the final flange geometry is accurate.
Solution Approach 2:
The distal portion of the preform creates preliminary tension in the plies that acts against the compressive forces that would cause wrinkling during bending. This preliminary anti-action prevents the harmful distortion before it can occur during the forming process.
3Productivity
If automated lay-up is used for the housing, then productivity increases, but it is difficult to integrate the flange with the housing
Solution Approach 1:
The manufacturing process is segmented into two distinct phases: automated machine lay-up for the main body and manual lay-up for the flange. This segmentation resolves the conflict by allowing automated processes to be used where possible while transitioning to manual processes where precision and flexibility are required for integration.
Solution Approach 2:
Instead of attempting to automate the flange integration (which would be difficult), the approach is inverted by using manual lay-up for the flange while keeping the main body automated. This reversal of the expected automation sequence simplifies the integration process.
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 improves the quality of the flange by reducing distortion and allowing for automated lay-up, resulting in a lighter and more consistent composite structure with enhanced stiffness and reduced material usage.
Implementation Method 1
a vacuum bag membrane for clamping
Implementation Method 2
a two-stage temperature process for curing
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Method forming a composite structure ( 9 ) comprising a main body and a flange. The composite structure is manufactured by laying -up a preform (7) on a mould (6). The preform (7) does not have the first and second bends and comprises a first part which corresponds to the main body of the composite structure and a second part which corresponds to the flange of the composite structure. The second part of the (preform (7) has a proximal portion which corresponds to the wall portion of the flange and a distal portion which corresponds to the lip portion of the flange. The preform (7) comprises a plurality of plies and uni - directional ply material extends from the first part of the preform (7) to the distal portion of the second part of the preform (7). The flange is formed by advancing movable portion (s) (62) of the mould 6 to form the proximal portion of the second part of the preform (7) to create the first bend (81) and by forming the distal portion of the second part of the preform (7) around the advancing movable portion (s) (62) of the mould (6) to create the second bend (83). The presence of the two bends (81, 83) ensures that the ply material (78) is kept in tension during the forming operation.