Monitoring of Layered Thermoplastic Composites Using Shape Memory Alloys as Integrated Sensors for Multifunctional...

Area of Science:

• Materials Science
• Composite Materials Engineering
• Structural Health Monitoring

Background:

• Lightweight design and construction safety are critical in various industries.
• Shape Memory Alloy (SMA) wires offer potential for improving mechanical property monitoring and adjustment in composites.
• Integrating SMA wires into composites can enhance understanding of applied forces throughout a product's lifecycle.

Purpose of the Study:

• To investigate the use of embedded SMA wires for monitoring forces applied to Glass Fiber Reinforced Polymer (GFRP) composite structures.
• To evaluate the effectiveness of different Non-Destructive Testing (NDT) methods for detecting embedded SMA wires.
• To correlate changes in SMA wire resistance with applied forces and determine optimal wire parameters.

Main Methods:

• Mechanical testing of GFRP samples containing embedded SMA wires.
• Application of NDT methods including active thermography, high-frequency ultrasonic testing, and computer tomography for SMA wire detection.
• Characterization of applied forces using relative resistance changes in SMA wires.
• Evaluation of SMA wire performance based on diameter and load-bearing capacity.

Main Results:

• Active thermography and computer tomography were identified as the most suitable NDT methods for detecting embedded SMA wires.
• The location and magnitude of applied forces on GFRP composites could be characterized by monitoring relative resistance changes in the SMA wires.
• SMA wires with a 250 µm diameter demonstrated superior performance, exhibiting a 25N force plateau compared to 4N for 100 µm wires.
• The average Young's modulus of the GFRP composites with embedded SMA wires was measured to be approximately 30.8 GPa.

Conclusions:

• Embedded SMA wires are effective for monitoring and understanding forces applied to GFRP composite structures.
• 250 µm SMA wires are recommended over 100 µm wires for improved performance and production.
• The study demonstrates a viable method for enhancing structural health monitoring in composite materials using embedded SMA technology.