Abstract
Carbon nanotube/polymer-based composites have led to studies that enable the realization of low-cost, high-sensitivity piezoresistive strain sensors. This study investigated the characteristics of piezoresistive multi-walled carbon nanotube (MWCNT)/epoxy composite strain sensors subjected to tensile and compressive loads in one direction at relatively small amounts of strain. A patterned sensor was designed to overcome the disadvantage of the load direction sensitivity differences in the existing sensors. The dispersion state of the MWCNTs in the epoxy polymer matrix with the proposed dispersion process was verified by scanning electron microscopy. An MWCNT/epoxy patterned strain sensor and a patch-type strain sensor were directly attached to an acrylic cantilever beam on the opposite side of a commercial metallic strain gauge. The proposed patterned sensor had gauge factors of 2.52 in the tension direction and 2.47 in the compression direction. The measured gauge factor difference for the patterned sensor was less than that for the conventional patch-type sensor. Moreover, the free-vibration frequency response characteristics were compared with those of metal strain gauges to verify the proposed patch-type sensor. The designed drive circuit compensated for the disadvantages due to the high drive voltage, and it was confirmed that the proposed sensor had higher sensitivity than the metallic strain gauge. In addition, the hysteresis of the temperature characteristics of the proposed sensor is presented to show its temperature range. It was verified that the patterned sensor developed through various studies could be applied as a strain sensor for structural health monitoring.
Highlights
Metallic strain gauges can be used to obtain stable measurements, properties like low flexibility and a non-embedded installation limit their application
The cut surfaces of multi-walled carbon nanotube (MWCNT)/epoxy patch-type sensors fabricated using the same process with various MWCNT concentrations were observed using scanning electron microscopy (SEM) to verify the dispersion of the proposed dispersion process
6, it can be seen that homogeneously, other than some partial small agglomerations. These results demonstrated that the the MWCNTs are randomly distributed in the epoxy polymer matrix, and the MWCNTs are dispersed the MWCNTs areother randomly insmall the epoxy polymer matrix, and the MWCNTs are structure
Summary
Metallic strain gauges can be used to obtain stable measurements, properties like low flexibility and a non-embedded installation limit their application. To replace metallic strain gauges in the structural health monitoring (SHM) field, much attention has been given to a sensor type capable of being mounted on a structure with a complex shape or embedded in a structure to improve SHM [1,2]. This has accelerated the research on smart materials [3,4,5,6]. Because there are various factors affecting the performance of the sensor, it is essential to accurately analyze these factors when fabricating the sensor
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
