Reconfigurable Mandrel for Composite Stiffener Forming
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Solution Overview
Problem
The production of contoured composite laminate stiffeners, such as those used in aircraft wings and fuselage, requires multiple sets of differently configured tools, leading to increased capital expenses and limited production rates due to space constraints and the need for forming tools that match unique geometries.
Innovation Solution
A method and apparatus that utilize a reconfigurable forming mandrel and former to form composite charges directly to the desired contour of the stiffener, reducing the need for multiple tool sets and allowing for the formation of stiffeners in a single operation, either hot or cold, with reduced ply wrinkling and without vacuum pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If multiple sets of differently configured tools are used to form contoured stiffeners, then the desired contours can be achieved, but capital expenses and floor space requirements increase
Solution Approach 1:
The patent employs a single reconfigurable tool that can be adjusted to form multiple different contours through variable support configurations. Instead of requiring separate dedicated tools for each contour type, the system uses adjustable supports and positioning mechanisms that allow one tool to perform the function of multiple specialized tools, thereby reducing capital expenses and floor space requirements while maintaining contour accuracy
Solution Approach 2:
The tooling system incorporates adjustable and reconfigurable components that can dynamically change their configuration to match different contour requirements. The supports and positioning elements can be moved, adjusted, or repositioned to accommodate various stiffener geometries, transforming a static tool into a dynamic, adaptable system that maintains precision across different shaping tasks
2Shape
If multiple sets of differently configured tools are used to form contoured stiffeners, then the desired contours can be achieved, but production rate is limited due to space constraints
Solution Approach 1:
By using a single reconfigurable tool that can form multiple contour types, the system eliminates the need to switch between different specialized tools for different contour requirements. This universality allows continuous production without tool changeovers, thereby increasing production rate while maintaining the ability to achieve accurate contours through adjustable configurations
Solution Approach 2:
The reconfigurable tool system allows for quick adjustment and setup between different contour configurations without requiring complete tool changes. The adjustable supports and positioning mechanisms can be rapidly reconfigured for the next production run, minimizing downtime and maintaining high production rates while preserving contour accuracy
3Ease of manufacture
If traditional forming methods are used, then stiffeners can be formed, but ply wrinkling occurs during the forming process
Solution Approach 1:
The patent employs a flexible membrane or film as the forming surface that conforms to the desired contour. This flexible forming tool allows the composite plies to be gradually shaped without creating sharp folds or wrinkles, as the membrane provides a smooth, continuous surface that guides the material flow during forming, thereby maintaining surface quality while enabling effective forming
Solution Approach 2:
The forming process uses adjustable and progressive application of force through the reconfigurable tool system, allowing the plies to be gradually formed to the desired contour without sudden deformations that would cause wrinkling. The dynamic adjustment of support positions and forming pressure enables controlled material flow and prevents surface defects
Data Source
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AI summary
A composite structure such as a stringer is produced by laying up composite charges at a layup station, spooling the charges onto a roll and transporting the roll to a forming station where the charges are unrolled and formed into individual components of the stringer. The components are then transferred to an assembly station where they are assembled together and vacuum bagged in preparation for curing.