Magnetic Hat Stringer Handling to Prevent Wrinkling
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Solution Overview
Problem
Conventional methods for handling uncured or partially cured hat stringers in aircraft construction, such as those made of fiber-reinforced composite materials, often result in undesired wrinkling and deformation due to the application of squeezing forces needed to lift and position these stringers, which can force the mandrel outward from the interior volume.
Innovation Solution
A magnetic handling system comprising a bladder with magnetic inserts and a magnetic carriage system that applies attractive magnetic forces to the interior and exterior surfaces of the stringer to lift, carry, and position the stringers without deforming them, allowing for even force distribution and manipulation into desired conformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional squeezing force is applied to lift and position uncured hat stringers, then the stringers can be handled and positioned, but the stringers experience deformation and wrinkling due to the concentrated force
Solution Approach 1:
The handling system divides the force application into multiple discrete magnetic attachment points distributed across the stringer surface. Instead of one concentrated squeezing force, multiple magnets create distributed attractive forces that lift and position the stringer without concentrating stress at any single location, thereby preventing deformation while maintaining handling capability
Solution Approach 2:
The patent replaces the conventional mechanical squeezing system with a magnetic field-based attraction system. The magnets embedded in the handling tool create magnetic attractive forces that act on ferromagnetic particles within the uncured stringer material, eliminating the need for mechanical clamps or squeezes that cause deformation, while still providing effective handling and positioning
2Ease of operation
If mandrel is used within stringer interior volume for support, then the stringer can be handled, but the squeezing force can force the mandrel outward from the interior volume
Solution Approach 1:
The magnetic handling system replaces mechanical squeezing and mandrel-based support with magnetic field attraction. The magnets in the handling tool directly attract ferromagnetic particles within the stringer material itself, eliminating the need for internal mandrels that could be forced outward by squeezing forces, while maintaining stable handling and positioning
3Ease of operation
If reinforcing cover is applied to exterior surface for protection, then the stringer can be handled, but additional squeezing force is needed which increases deformation risk
Solution Approach 1:
The magnetic handling system replaces mechanical squeezing force with magnetic field attraction. The magnets in the handling tool create attractive forces that act on ferromagnetic particles within the stringer material, eliminating the need for reinforcing covers and the additional squeezing force they would require, thereby reducing deformation risk while maintaining handling capability
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
The magnetic handling system effectively prevents deformation of uncured or partially cured hat stringers by evenly distributing forces across their thickness, enabling precise placement and conformation to non-planar aircraft surfaces during installation.
Implementation Method 1
A magnetic handling system comprising a bladder with magnetic inserts and a magnetic carriage system that applies attractive magnetic forces to the interior and exterior surfaces of the stringer
Implementation Method 2
The magnetic handling system effectively prevents deformation of uncured or partially cured hat stringers by evenly distributing forces across their thickness
Data Source
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AI summary
The magnetic handling systems comprise a bladder and a magnetic carriage system. The bladder is configured to be received within a stringer interior volume of a hat stringer and comprises a magnetic insert having a plurality of magnetic walls, each configured to align with a respective wall portion of the hat stringer. The magnetic carriage system comprises a carriage having a magnetic head that comprises a bracket and a plurality of magnetic sources supported by the bracket. Each magnetic source is configured to magnetically couple with a respective magnetic wall of the magnetic insert to produce an attractive magnetic force therebetween. The methods comprise disposing a bladder having a plurality of the magnetic inserts within the hat stringer, magnetically engaging a plurality of the magnetic heads with the plurality of magnetic inserts, and conforming the hat stringer by moving at least one magnetic head relative to another magnetic head.