Multi-scale modeling is conducted in the current work to investigate the stretching effects upon the electrical conductivity of carbon nanotube (CNT)-polymer composites. A mixed micromechanics model is developed with the incorporation of the nano-scale electron hopping and the micro-scale conductive networking. Stretching is expected to induce volume expansion of the composites, re-orientation of CNTs and change in conductive networks, which are characterized in the current model by the variation of the CNT concentration, the CNT orientation distribution function and the percolation threshold, respectively. Simulation results show that stretching decreases the electrical conductivity more significantly for the composites with lower volume fraction than those with higher volume fraction. As compared to a uniaxial stretching, the decreasing rate of the electrical conductivity of the CNT-polymer composites enhances under a bi-axial stretching loading condition. This work is expected to provide a qualitative prediction on the trend of the stretching effects upon the electrical properties of CNTpolymer composites.
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