Composite Flange Edge Quality via Preliminary Trimming
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Solution Overview
Problem
The manufacturing of structural members with flanges in the aeronautical industry faces issues such as undesirable stepped edges due to ply sliding during hot forming, leading to complex processing and structural distortions during co-bonding with composite panels.
Innovation Solution
A structural member with a flange edge featuring a smooth, sloped surface is manufactured using a mandrel with a sloped forming surface, allowing plies closer to the concave side to fold towards those on the convex side, eliminating the need for trimming and reducing material consumption and processing time, while enhancing material adaptation during curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a hot forming process is used to create flanges, then the flanges can be formed with the required shape, but the plies slide relative to each other creating stepped edges that require additional trimming operations
Solution Approach 1:
The invention applies preliminary trimming before the hot forming process. The laminated part is trimmed to a reduced width in the planar state before folding, so that after forming the flange, the edges align properly without creating stepped appearances. This preliminary action prevents the edge quality problem rather than correcting it after formation.
Solution Approach 2:
The invention addresses the edge quality issue by operating in the planar dimension before folding occurs. By trimming the laminated part in its flat state rather than attempting to correct edges after three-dimensional folding, the solution transforms the problem from a post-forming correction challenge to a pre-forming preparation step.
2Manufacturing precision
If plies are arranged to compensate for sliding effect to provide perpendicular edge, then edge quality improves, but processing complexity and material consumption increase
Solution Approach 1:
Instead of complicating the ply arrangement to compensate for sliding, the invention performs a simple preliminary trimming operation before forming. This reduces processing complexity while achieving the desired edge perpendicularity through a straightforward cut rather than complex ply positioning.
Solution Approach 2:
The invention extracts the problematic sliding effect from the equation by trimming the excess material before it can cause issues during forming. Rather than trying to manage the sliding plies through complex arrangements, the solution removes the unnecessary material that would create stepped edges in the first place.
3Ease of manufacture
If traditional flange edges are used in co-bonding process, then assembly can proceed, but the flange sinks into unconsolidated panel material causing fibre distortions
Solution Approach 1:
The invention performs preliminary trimming before co-bonding to create properly aligned edges. This prevents the flange from sinking into the panel material during assembly, maintaining structural integrity while still enabling the co-bonding process to proceed. The pre-trimmed edges provide a stable interface that resists deformation under compression.
Solution Approach 2:
The preliminary trimming creates an edge configuration that anticipates and prevents the sinking problem during co-bonding. By preparing the edges in advance with the correct geometry, the invention counteracts the potential harmful effect of flange intrusion into unconsolidated material before the co-bonding process begins.
Data Source
Figure 1~2
Figure 3
AI summary
Structural member (10) composed of assembled plies of fibre material embedded in a resin matrix, and comprising at least one laminated part (17) formed by a plurality of these plies arranged in a stacking relationship, wherein the laminated part of the structural member (10) is folded in such a way as to form a flange (13) defining an inner angle (α) with respect to a base portion (19) of the laminated part (17). The edge (13a) of the flange forms a sloped surface on the concave side of the laminated part (13), at which sloped surface the plies of the flange (13) which are closer to the concave side of the laminated part (17) are folded towards the ply of the flange (13) positioned on the convex side of the laminated part (17), in such a way as to cause their ends to be substantially level with the face (15) of the flange (13) on the convex side of the laminated part (17).