Composite Charge Punch Forming for Tapered Stringer Production
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Solution Overview
Problem
Traditional methods of composite stringer punch forming do not account for a taper in the cross-section, limiting the ability to produce tapered stringers that could reduce weight or improve performance in aircraft designs.
Innovation Solution
A punch forming method that utilizes a forming tool driven by a plurality of actuators operating at varying rates to generate a variable cross-section in a composite charge, allowing for the creation of tapered stringers by compensating for geometric changes along the length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If traditional punch forming methods are used with constant actuator rates, then constant cross-section stringers can be produced, but tapered cross-section stringers cannot be produced
Solution Approach 1:
The system transitions from static, uniform actuator operation to dynamic, variable-rate actuator operation. Each actuator's speed is independently controlled to match the local taper requirements, enabling the forming tool to adapt its deformation rate across different positions along the stringer length, thus producing tapered cross-sections while maintaining process control
Solution Approach 2:
The patent applies different actuator rates at different locations along the forming tool. By controlling each actuator to operate at a rate specific to its position, the system creates localized deformation characteristics that match the desired tapered geometry, with faster rates at regions requiring greater material displacement and slower rates at regions requiring less displacement
2Shape
If traditional punch forming methods are used, then manufacturing process is simple, but tapered cross-sections cannot be produced
Solution Approach 1:
The system changes the operational parameters of the actuators from uniform speed to variable speed. By adjusting the speed parameter of each actuator based on its position and the local taper requirements, the system enables tapered cross-section production while maintaining a relatively simple mechanical forming apparatus, with complexity confined to the control system
3Shape
If actuators operate at different rates, then variable cross-section can be generated, but synchronization control becomes challenging
Solution Approach 1:
The system implements feedback control to monitor and adjust actuator positions and speeds in real-time. This ensures that despite operating at different rates, all actuators remain synchronized with their target positions, maintaining forming accuracy and preventing defects such as wrinkles or delamination that could result from unsynchronized operation
Data Source
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AI summary
Methods of punch forming a composite charge are presented. A forming tool is placed in contact with a composite charge. A plurality of actuators connected to the forming tool is simultaneously activated to drive the forming tool towards the composite charge. The plurality of actuators is driven at a plurality of rates to generate a variable cross-section in the composite charge. The plurality of actuators is simultaneously stopped.