A multiscale modeling of CNT-reinforced cement composites

A multiscale approach for computational modeling of the mechanical behavior of carbon nanotube (CNT) reinforced cement composites is presented. In a macroscopic scale treatment, reinforcement is assumed to be embedded in the overall domain in the corresponding volume fraction. Accounting for the volume fraction, orientation and arrangement of the reinforcing components, CNTs and a matrix are simulated by different nonlinear constitutive models to represent the composites, CNTs are considered as one-dimensional and distributed in a uniform orientation. A mesoscopic scale description is considered in order to depict the mesostructured morphology of the reinforced composites and the bond-slip of its mutual interaction. Two length-scale systems of equations are coupled together using a staggered technique, and the Newton-Raphson method is adopted to solve the nonlinear system equations in order to track the full load-displacement path of the composites. A number of available experimental tests are reproduced by which to illustrate the feasibility of the proposed model, which proves to be effective in the nonlinear framework. Meanwhile, computational accuracy and efficiency are also demonstrated through the solving of several benchmark problems.