Evaluation of effective material parameters of CNT-reinforced composites via 3D BEM

In recent years, carbon nanotubes (CNTs) have been widely employed to build advanced composites. In this work, a Boundary Element Method (BEM) is applied to 3D representative volume elements (RVEs) to estimate mechanical properties of CNT-based composites. To model the thin-walled nanotubes, special integration procedures for calculating nearly-strongly-singular integrals have been developed. The generic BE substructuring algorithm allows modeling complex CNT-reinforced polymers, containing any number of nanotubes of any shape (straight or curved). The subregion-by-subregion strategy, based on Krylov solvers, makes the independent generation, assembly, and storage of the many parts of the complete BE model possible. Thus, significant memory and CPU-time reductions are achieved in avoiding working with an explicit global system of equations. Further CPU-time reduction is obtained by employing a matrix-copy option for repeated subregions. Several applications will illustrate the ability of this algorithm to analyze CNT-based composites.