Coupled electromechanical modeling of piezoresistive behavior of CNT-reinforced nanocomposites with varied morphology and concentration

In this first time effort, we developed a coupled electromechanical model of CNT-reinforced composites with realistic morphologies. First, a Monte-Carlo based algorithm was developed to generate representative volume elements (RVEs) reinforced with different concentrations of straight and wavy CNTs. The percolating CNT networks were identified and transformed into an equivalent electric circuit consisting of tunneling and intrinsic resistances. The effective conductivity of the composite was then obtained using the modified nodal analysis method. Second, the structural response of each RVE was obtained using a novel embedded finite element model, where the composite constituents are meshed independently but solved simultaneously by coupling their equilibrium equations. Third, the displacements of the deformed CNTs were updated in the electrical model to calculate the corresponding tunneling distances and the resistance of the deformed system. The gauge factor of the nanocomposite was calculated from the strain-resistance curve. The obtained results indicated that the gauge factor increases with the increase in the curvature of the CNTs. The highest gauge factor of the sensor was attained at concentrations near the percolation threshold. Finally, the gauge factor was found to increase with the decrease in Poisson's ratio of the matrix. [Display omitted] •Novel coupled electromechanical model of CNT composites with realistic morphologies.•Percolating networks converted into equivalent electric circuits.•Modified nodal analysis method used to determine conductivity of the composite.•Sensor gauge factor increases with the increase in curvature of CNTs.•Sensor gauge factor was highest at concentrations near percolation threshold.