An equivalent continuum meshless approach for material nonlinear analysis of CNT-reinforced composites

This paper investigates the mechanical properties of CNT-reinforced composites via meshless method, and material nonlinearity of its constituents is considered. An equivalent continuum simulation is employed to evaluate the microstructure of CNTs, based on that, both two-dimensional simplified and three-dimensional models are introduced separately. A plasticity model is adopted in the interface between reinforcement and matrix. The effect of van der Waals forces between CNTs is also considered by uniformly aligned transverse springs, which are continuously connected to nanotubes along their length. Parametric studies of the mechanical properties with varying spring stiffness are carried out to prove the suitability of Winkler's multi-spring model. The governing equations of motion are obtained by establishing energy functional, and displacement fields in the spatial domain are discretized by the moving least-squares (MLS) approximation. The effects of length of reinforcement, node distribution and influence domain are also investigated, and the stability and precision of the presented meshless method are validated by convergence and comparison studies.