Strain sensing with CNT nanocomposites: static, cyclic and dynamic electromechanical material characterization.

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Carbon Nanotube (CNT) nanocomposites are one of the most important candidates to realize innovative strain sensors for Structural Health Monitoring (SHM) applications. In this work, sensors were made of Multi-walled Carbon Nanotubes (MWNTs) embedded in a PolymethylMethacrylate (PMMA) matrix. The capability of the sensor to sense strain is due to the conductive paths formed by the random MWNTs dispersed within the insulating PMMA matrix. The material conductivity changes when the nanocomposite is strained because the conductive paths modify the composites morphology at nanoscale. Continuous monitoring for deformations is possible by correlating these electrical variations to the level of deformation of the material. Different specimens were made by varying the MWNTs content (3%, 5%, 7%, weight fractions) and were tested under varying static, cyclic and dinamic loading conditions. It is found that the Gauge Factor (GF) and sensor sensitivity are directly related to the MWNTs content. Sensors with higher MWNTs percentages (7%) showed the best behaviour with a smaller dispersion of the experimental data. The higher reproducibility is comparable to that of conventional strain gauges. This nanocomposite strain sensor, is ultralight, flexible and allows to monitor larger areas if it is compared with the commercially available strain gauges. The material is an ideal solution for monitoring the incipient (nano/micro-scaled) cracks due to the sensitivity to nanoscale morphology changes. The research leading to these results was supported by the European Research Council under the European Union’s Seventh Framework Program (FP/2007-2013)/ERC Grant Agreement n. 308261

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Journal: TechConnect Briefs
Volume: 1, Advanced Materials: TechConnect Briefs 2018
Published: May 13, 2018
Pages: 50 - 53
Industry sectors: Advanced Materials & Manufacturing | Sensors, MEMS, Electronics
Topic: Carbon Nano Structures & Devices
ISBN: 978-0-9975117-8-9