Abstract
Here we discuss the characterization and modeling of a relatively new class of embedded artificial hair sensors. The sensors take advantage of the mechanical properties of structural S2 glass microfibers as the hair element and the electromechanical properties of self-aligned carbon nanotube arrays to rapidly transduce small changes in force or displacement into changes in resistance. While traditionally envisioned for air flow sensing, this approach can also provide fundamental understanding of the electrical and mechanical properties of fuzzy fibers and may have additional applications to structural monitoring. The materials of the entire sensor are chosen to survive CNT synthesis conditions (700°C, inert atmosphere) as well as the typical processing and operating conditions for aerospace composite skin materials. Each sensor is individually contained within a small footprint. While other hair sensor designs suffer from reduction in bandwidth due to mechanical coupling of the hair by the transducer, our models indicate that the stiffness of the distributed CNT array supporting the S2 fiber is high relative to the low mass of the fiber. As a result the resonance frequency of the hair is maximized as if rigidly fixed at its base (e.g. the opening of the pore), yet the base of the hair deflects enough to induce a resistance change. In comparison to other published results, we believe these sensors display the highest sensitivity for air velocities less than 10 m/s. The electromechanical responses of the sensors to both point loads and to the distributed loads from airflow are compared, and their responses under both quasi-static and dynamic conditions are correlated to the mechanical properties of the hair and nanotubes. Employing the sensors to measure the mechanical strain in composites is also investigated.
Original language | English (US) |
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State | Published - 2015 |
Externally published | Yes |
Event | 20th International Conference on Composite Materials, ICCM 2015 - Copenhagen, Denmark Duration: Jul 19 2015 → Jul 24 2015 |
Other
Other | 20th International Conference on Composite Materials, ICCM 2015 |
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Country/Territory | Denmark |
City | Copenhagen |
Period | 7/19/15 → 7/24/15 |
Keywords
- Air flow sensing
- Artificial hair sensor
- Carbon nanotube array
- Plane-
- Shear sensing
ASJC Scopus subject areas
- General Engineering
- Ceramics and Composites