Modeling the DC and AC electromechanically coupled effects in CNT‐based nanocomposite sensors

Abstract The direct current (DC) and alternative current (AC) electromechanically coupled phenomena have been reported in carbon nanotube (CNT)‐based nanocomposite sensors. In this contribution, a unified micromechanics‐based model is established for the DC and AC strain sensors. The electric damage and volume change of nanocomposite are considered to be responsible for the electromechanically coupled effects in CNT‐based nanocomposite sensors. The predicted DC resistance change ratio, AC dielectric loss change ratio and corresponding strain sensitivity factors of CNT‐based nanocomposite sensors are all consistent with the experimental results. High strain sensitivity is achieved for CNT‐based nanocomposite sensors with a low CNT‐content. This study confirms the advantage of adopting CNT‐based nanocomposite sensors via the dielectric loss over the electric resistance. The present electromechanically coupled homogenization theory can be utilized to rapidly determine the macroscopic DC and AC sensing performance by choosing a specific set of microstructural parameters, and further simplify the design process of CNT‐based nanocomposite sensors.