Share Email Print
cover

Proceedings Paper

"Smart Skin" optical strain sensor using single wall carbon nanotubes
Author(s): Peng Sun; Ji-Hoon Kim; Sergei M. Bachilo; R. Bruce Weisman; Satish Nagarajaiah
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

Strain measurements are essential in structural health monitoring. Traditional strain gages require physical contact between the sensor and read-out device, perturb the surface being monitored, and allow measurement only at the specific location and orientation axis of the sensor. We demonstrate a novel non-contact, multi- point, multi-directional strain sensing approach that overcomes these limitations. In our method, the surface is coated with a thin film of "smart skin" containing individualized single-walled carbon nanotubes in a polymeric host. After curing, substrate strains are transmitted through the polymer film to embedded nanotubes. This induces axial strains in the nanotubes, systematically shifting the wavelengths of their characteristic near-infrared fluorescence peaks. To measure strain, a visible laser excites nanotubes at points of interest on the surface, and the near-infrared emission is collected and spectrally analyzed. Observed spectral shifts reveal quantitative strain values. Laboratory tests show sensitivity down to ~400µm, limited by mechanical properties of the polymeric host film. We also vary excitation beam polarization to find the axis of substrate strain. Our method provides spatial resolution down to its gage length of ~100µm. Because the entire substrate is coated with nanoscale strain sensors, measurements can be made at arbitrary locations to construct a full strain map. We will describe recent smart skin refinements involving selection of polymer host, nanotube surfactant, nanotube dispersion method, and preparation protocol. Finally, we characterize the orientational distribution of nanotubes using a probabilistic model.

Paper Details

Date Published: 10 April 2014
PDF: 13 pages
Proc. SPIE 9061, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2014, 906120 (10 April 2014); doi: 10.1117/12.2046539
Show Author Affiliations
Peng Sun, Rice Univ. (United States)
Ji-Hoon Kim, Rice Univ. (United States)
Sergei M. Bachilo, Rice Univ. (United States)
R. Bruce Weisman, Rice Univ. (United States)
Satish Nagarajaiah, Rice Univ. (United States)


Published in SPIE Proceedings Vol. 9061:
Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2014
Jerome P. Lynch; Kon-Well Wang; Hoon Sohn, Editor(s)

© SPIE. Terms of Use
Back to Top