Electroactive Mesh Reinforcement for Force-Fit Structural Profiles
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Solution Overview
Problem
Existing structural profiles in aircraft and spacecraft require complex and costly attachment methods for reinforcing elements, which can be heavy and inflexible, lacking efficient solutions for axial load absorption and tolerance compensation.
Innovation Solution
A reinforcing element with a hollow-cylindrical, helically wound mesh of fiber strands embedded in an electroactive polymer matrix that expands under electrical voltage to fit around structural profiles, providing a force-fit connection and adjustable stiffness for improved resistance to bending and axial loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional holders with transverse webs and pins are used to attach reinforcing elements to structural profiles, then form-fitting axial securing is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The invention extracts the essential function of axial securing from the complex holder structure and implements it directly through the electroactive polymer's shrinkage mechanism. The holder components (transverse webs, pins, bores) are eliminated entirely, replacing them with a simple tubular reinforcing element that shrinks radially to engage the structural profile surface, retaining only the necessary axial securing function.
Solution Approach 2:
The invention replaces the mechanical pin-and-bore connection system with an electroactive polymer shrinkage mechanism. Instead of using mechanical elements (pins, webs, holders) to achieve form-fitting securing, the patent uses an electrically controllable material that changes its dimensions through electrochemical actuation, substituting a complex mechanical assembly with a smart material-based system.
2Ease of operation
If thermoplastic matrix material is used for the composite structure, then shrinking by heating is achieved, but manufacturing complexity and energy consumption increase
Solution Approach 1:
The invention replaces thermal actuation with electrical actuation. Instead of using heat to trigger the phase transition and shrinkage of thermoplastic matrix material, the patent employs an electroactive polymer that responds to electrical voltage by changing its molecular conformation and shrinking. This substitutes a thermal process requiring external heating energy with an electrical process that is more controllable and energy-efficient.
Solution Approach 2:
The invention changes the actuation parameter from temperature to electrical voltage. The electroactive polymer's shrinkage is triggered by applying a specific voltage threshold, allowing precise control over the shrinking process. This parameter change enables on-demand activation, reversible operation, and eliminates the need for sustained thermal energy input required by thermoplastic materials.
3Strength
If the composite structure is shrunk for force-fit connection, then resistance to bending increases, but the structure becomes less adaptable to installation adjustments
Solution Approach 1:
The invention introduces dynamic reversibility to the connection system. The electroactive polymer can be activated and deactivated repeatedly, allowing the reinforcing element to expand and contract on demand. During installation, the polymer remains expanded for easy positioning and tolerance compensation; once positioned, it shrinks to provide force-fit connection and enhanced bending resistance. This dynamic behavior enables both adaptability during installation and strength during operation.
Solution Approach 2:
The invention performs the expansion action preliminarily during the installation phase, allowing the reinforcing element to be easily positioned and adjusted before final connection. The electroactive polymer is activated in advance to create an expanded state that facilitates tolerance compensation and alignment, then deactivated to create the shrunk force-fit state that provides structural reinforcement. This separation of installation phase (expanded) and operational phase (shrunk) enables both adaptability and strength.
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
Enables simplified, lightweight, and cost-effective reinforcement of structural profiles with enhanced resistance to bending and axial loads, including crash scenarios, while eliminating the need for thermoplastic matrix shrinking and allowing for repeated installation adjustments.
Implementation Method 1
which has an electroactive polymer which can be stretched along a longitudinal extent of the fiber strands by application of an electrical voltage
Implementation Method 2
can be shrunk by switching off the electrical voltage in order to fix the structural profile on the shell surface in the composite structure
Data Source
AI summary
A reinforcing element for a structural profile, in particular for a round, oval or elliptical structural tube, includes a composite structure, which has a hollow-cylindrical, helically wound mesh of fiber strands which form an inner shell surface configured to receive the structural profile, wherein the fiber strands are respectively embedded in a matrix material, which has an electroactive polymer which can be stretched along a longitudinal extent of the fiber strands by application of an electrical voltage, such that the composite structure can be expanded by application of 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 on the shell surface in the composite structure.