Abstract

In the field of structural health monitoring, in-situ monitoring is always a challenge. One way to solve this issue is to create a multi-functional material, such as composite modified by carbon nanotubes (CNTs). However, fewer work were focused on the “hard” CNTs/Epoxy resin composite created by thermoset polymer matrix, which can both provide sufficient load capacity and self-sensing ability. In this work, the mechanical behavior of CNTs/Epoxy resin composite was evaluated by a cantilever bending test. Both metal wire strain gauge and fiber Bragg grating (FBG) sensor were pasted onto the beam surface. The strain measured by FBG sensor showed high sensitivity and accuracy, which was in good accordance with the results form strain gauge and numerical simulation. What’s more, the piezo-resistance behavior of this CNTs/Epoxy resin composite was evaluated by a DC voltage dividing circuit. When the tensile stress (2.6MPa) applied on the beam sample, a ratio of resistance variation of 0.013 was observed and compared with numerical simulation. The gauge factor of the CNTs/Epoxy composite was calculated as 17.6. Preliminary modeling for such piezo-resistance behavior was failed. New theoretical model considering the integral geometry of the electrodes and the coupling piezo-resistance coefficient should be further investigated.

© 2018 The Author(s)