Electroactive Braided Reinforcement for Hole-Free Tube Attachment
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Solution Overview
Problem
Current methods for attaching reinforcing elements to structural profiles, such as tubes in aircraft or spacecraft, are complex and require multiple steps or materials that are not easily adjustable or reusable, limiting their efficiency and flexibility in handling axial loads.
Innovation Solution
A reinforcing element with a hollow cylindrical helically wound braid of fiber strands embedded in an electroactive polymer matrix that expands under electrical voltage to accommodate structural profiles and shrinks to securely attach them, providing a non-positive connection that enhances buckling stiffness and frictional adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional holders with transverse bores and pins are used to attach structural profiles, then positive axial securing is achieved, but the connection process becomes complex and requires pre-drilled holes
Solution Approach 1:
The patent replaces the traditional mechanical pin-and-hole connection system with an electroactive polymer-based actuating mechanism. The electroactive polymer material changes its mechanical properties (expands or contracts) in response to electrical voltage, enabling the holder to securely attach the structural profile without requiring pre-drilled holes or separate pin components, thus simplifying the connection process while maintaining axial securing reliability
Solution Approach 2:
The holder utilizes electroactive polymer material that changes its physical dimensions (expands or contracts) in response to changes in electrical voltage parameters. This parameter-driven transformation allows the holder to transition between different states (e.g., insertion state and locked state), enabling a simplified single-step connection process that eliminates the need for complex multi-component assembly
2Ease of manufacture
If thermoplastic matrix material is used for the reinforcing element, then attachment via shrinking by heating is achieved, but temperature-dependent materials and processes are required
Solution Approach 1:
The patent substitutes thermal actuation mechanisms with electroactive polymer-based actuation. Instead of using heat to shrink the thermoplastic matrix material, the invention employs electrical voltage to directly actuate the holder through the electroactive polymer material, which changes its dimensions in response to electrical fields. This eliminates the need for temperature-dependent materials and heating processes, simplifying manufacturing while maintaining the shrinking/expanding attachment functionality
Solution Approach 2:
The invention transitions from temperature-based parameter control to electrical voltage-based parameter control. The electroactive polymer material responds to changes in electrical voltage by expanding or contracting, replacing the thermal response of thermoplastic materials. This parameter substitution eliminates the need for heating equipment and temperature management, reducing manufacturing complexity while achieving the same dimensional transformation effect
3Reliability
If structural profiles require pre-drilled holes for connection, then secure attachment is achieved, but the structural integrity and buckling resistance are reduced
Solution Approach 1:
The patent replaces the hole-drilling and pin-insertion mechanical connection system with an electroactive polymer-based expansion/contraction attachment mechanism. The holder is actuated by electrical voltage to expand or contract, enabling it to securely grip the structural profile surface without penetrating it with holes. This surface-level attachment method preserves the structural profile's integrity and buckling resistance while achieving reliable secure attachment through the actuating material's dimensional changes
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 solution simplifies the connection process, reduces weight, eliminates the need for temperature-dependent materials, and allows for repeated assembly and disassembly, while providing enhanced buckling stiffness and adhesion, especially under crash loads, with the ability to connect components without pre-drilled holes.
Implementation Method 1
the fiber strands each being embedded in a matrix material which has an electroactive polymer which can be moved along by applying an electrical voltage
Implementation Method 2
can be shrunk by switching off the electrical voltage in order to fix the structural profile in the composite structure on the lateral surface
Data Source
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AI summary
A reinforcing element for a structural profile, in particular for a round, oval or elliptical structural tube, comprises a composite structure having a hollow cylindrical helically wound braid of fiber strands forming an inner surface designed to receive the structural profile, wherein the fiber strands are each embedded in a matrix material comprising an electroactive polymer that is stretchable by applying an electrical voltage along a longitudinal extension of the fiber strands, so that the composite structure can be expanded by applying the electrical voltage to introduce the structural profile into the composite structure, and can be shrunk by switching off the electrical voltage to fix the structural profile in the composite structure on the outer surface.