Flat Composite Charge Folding for Blade Stiffener Co-Cure
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Solution Overview
Problem
The manufacturing of composite blade stiffeners is labor-intensive and time-consuming due to the need for multiple tools and post-cure trim operations, and existing methods do not allow for the direct application of barely visible impact damage (BVID) treatments before curing, increasing costs and complexity.
Innovation Solution
A method involving assembling a flat composite charge with 45-degree beveled edges, applying a reinforcement ply, and using a tooling plunger to fold the charge into a forming mandrel, enabling the application of BVID treatment before curing in a single process, thus eliminating post-cure trim operations and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple separate charges are used to fabricate blade stringers, then the structural strength is improved, but the manufacturing complexity and labor intensity increase
Solution Approach 1:
The patent merges multiple separate charge fabrication processes into a single integrated forming operation. By using a monolithic charge with pre-formed flanges that are folded and co-cured in one autoclave cycle, the method eliminates the need for multiple separate charges and their associated tools, while maintaining the structural strength benefits of multi-component assembly.
Solution Approach 2:
The patent segments the single charge into functional regions (web and flanges) that are formed from one piece of composite material. The charge is designed with specific geometric features (45-degree beveled edges, flange configurations) that allow it to be folded and co-cured into the final blade stringer structure, achieving both strength and manufacturing simplicity.
2Reliability
If post-cure trim operations are performed to apply BVID treatment, then the impact damage protection is improved, but the manufacturing time and cost increase
Solution Approach 1:
The patent incorporates the BVID treatment as an integral part of the charge design, with the treatment material applied and cured together with the main composite structure in a single autoclave cycle. This preliminary integration eliminates the need for separate post-cure trim operations and surface preparation steps, reducing manufacturing time while maintaining impact damage protection.
Solution Approach 2:
The patent merges the BVID treatment application with the main curing process. The treatment material is positioned on the charge before forming, and both the structural composite and the BVID treatment are co-cured in the same autoclave cycle, eliminating sequential operations and reducing overall manufacturing time.
3Ease of manufacture
If a single charge is used to form the blade stiffener, then the manufacturing process is simplified, but the ability to apply BVID treatment before cure is limited
Solution Approach 1:
The patent applies different properties to different regions of the single charge. The charge is designed with specific local features (45-degree beveled edges for folding, flange configurations for web formation, and designated areas for BVID treatment material) that enable both simplified manufacturing and BVID treatment integration within the unified structure.
Data Source
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AI summary
There is described a method comprising: (a) assembling a flat composite charge (100) to a thickness in a predetermined orientation; (b) forming a cut line (114) on the flat composite charge having opposing 45 degree beveled edges angled outward from the cut line; (c) positioning the flat composite charge centered about a tooling plunger (132) such that the tooling plunger is aligned with the cut line; and (d) activating the tooling plunger to move downward and fold the flat composite charge at the cut line into a cavity (134) of a forming mandrel (126, 128). At completion of movement of the tooling plunger and resulting folding of the flat composite charge, the opposing 45 degree beveled edges form a flat surface perpendicular to the cut line and form a first flange (136) and a second flange (138) connected to the flat surface.