This paper presents the development of a numerical framework for modeling of composite materials based on carbon nanotubes that are used in strain sensors. The proposed model allows for multiscale analysis of electro-mechanical properties of such systems. The model is composed of three scales, namely nano-, meso- and macro-scale. The nano-scale model bases on Molecular Dynamics simulations and provides information about elastic properties and density of the polymeric material and carbon nanotubes. Furthermore, the meso-scale model employs the Finite Element discretization and utilizes information from nano-scale for its constituents. At the meso-scale, electro-mechanical behavior of the CNT/polymer composite is investigated. Finally, stresses and conductivity from the meso-scale model are coupled to the macro-scale using the Hill-Mandel principle. Numerical framework is then validated and compared to experimental results.