Composite Panel Stiffening Member Curing Process
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Solution Overview
Problem
Existing methods for manufacturing composite panels with stiffening members, such as cocured joins, often require multiple machining and rivet installation steps, leading to increased weight, higher manufacturing costs, and additional curing cycles, especially when using adhesives or traditional stiffening tools.
Innovation Solution
A process involving preimpregnated composite laminates for shaping U-shaped and I-shaped stiffening members, where these members are shaped on individual tools, assembled, and integrated with the panel skin within a single curing cycle using external tools to ensure verticality under autoclave pressure, eliminating the need for internal stiffening tools and reducing machining operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional cocured joins with internal stiffening tools are used, then stiffening members can be integrated with the panel skin, but multiple machining and rivet installation steps are required increasing device complexity and manufacturing time
Solution Approach 1:
The invention extracts the stiffening members from the internal tooling and makes them separate attachable components. The U-shaped stiffening members are pre-formed externally and then attached to the panel skin during curing, eliminating the need for complex internal tooling and subsequent rivet installation steps.
Solution Approach 2:
The stiffening members are pre-formed and prepared outside the autoclave before being attached to the panel skin. This preliminary preparation of stiffening members allows for simpler integration during the curing process and eliminates the need for internal tooling complexity.
2Weight of moving object
If adhesive bonds are used for joining stiffening members, then structure weight increases and multiple curing cycles are required, but surface preparation methods are avoided
Solution Approach 1:
The invention merges the stiffening member attachment process with the panel skin curing process into a single integrated operation. The stiffening members are attached and cured simultaneously in one autoclave cycle, eliminating the need for separate adhesive bonding operations and multiple curing cycles.
3Reliability
If surface preparation methods are used for adhesive joins, then join strength is improved, but manufacturing time and process complexity increase
Solution Approach 1:
The invention eliminates the surface preparation step by extracting the stiffening members from adhesive bonding and using direct mechanical attachment during curing. The U-shaped stiffening members are attached directly to the panel skin without requiring surface preparation, thereby reducing manufacturing time while maintaining join integrity.
4Manufacturing precision
If internal stiffening tools are used during curing, then stiffening members can be properly formed, but device complexity and manufacturing cost increase
Solution Approach 1:
The invention extracts the stiffening function from internal tooling and implements it through separate U-shaped stiffening members that are attached to the panel skin. This eliminates the need for complex internal tooling while maintaining the structural integrity and formation accuracy of the stiffening members.
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 process enables the production of lightweight, stiffened composite panels with reduced manufacturing costs and fewer curing cycles, achieving enhanced structural performance and weight reduction by integrating stiffening members directly during the resin curing process.
Implementation Method 1
when the resin is cured the two elements remain attached to one another
Implementation Method 2
consolidating the panel by means of a curing process under suitable pressure and temperature conditions
Implementation Method 3
Placing a vacuum bag on the panel fitting it as much as possible to the contour of the stiffening members
Data Source
AI summary
The present invention relates to a process for manufacturing panels (9) for aeronautical structures with U-shaped stiffening members (13) and I-shaped stiffening members (17) between their webs comprising the following steps: providing laminates for shaping the skin (11) on the curing tool (31); providing planar laminates (23) for shaping the stiffening members (13, 17); shaping the U-shaped stiffening members (13) on individual shaping tools (33) and placing the I-shaped stiffening elements (17) in said tools; grouping said individual shaping tools (33) together on an assembly tool (41); placing the group of stiffening members (13, 17) on the skin (11); placing a vacuum bag (55) on the assembly with the aid of profiles (59); consolidating said assembly by means of a curing process under suitable pressure and temperature conditions using external tools (60) to assure verticality of the webs of the stiffening members (13, 17).