The electro-mechanical behavior of conductive filler reinforced polymer composite undergone large deformation: A combined numerical-analytical study

The electro-mechanical performance of flexible strain sensors under large deformation is of great concern due to their applications in measuring large strain. In this paper, we develop a combined numerical-analytical approach to study the electro-mechanical behavior of conductive filler reinforced polymer composite under uniaxial tensile load. This developed approach couples the displacement field of the microstructure and the evolution of the micro circuit. A 2D micromechanical representative volume element model is used to simulate the deformation and strain field in the composite, taking into consideration the random distribution of conductive aggregates and the hyperelastic mechanical properties of the polymer matrix. We then predict the evolution of electrical resistance using the tunneling conduction theory and transfer-matrix approach, based on the strain distribution of the material under various tensile deformations. The numerical results agree well with experimental results in terms of different material parameters and tensile conditions. This suggests the developed model is capable of predicting the nonlinear electro-mechanical response of the studied material under large deformation and revealing the effect of particle mass fraction on the electro-mechanical performance. The present approach can be served as a useful tool in the design and improvement of conductive filler-polymer composites for flexible strain sensor application.