Simulation of CNT Composites using Fast Multipole BEM

In recent years, the fast multipole boundary element method (FM-BEM) has attracted the interest of many researchers. It is proved that FM-BEM can solve some very large scale problem, which is difficult to solve by FEM and other methods. One of the urgent affairs is to find such practical problems in engineering and sciences. The simulation of CNT composites is perhaps one of such problems. In this paper, FM-BEM is applied to simulate the elastic property of carbon nanotube reinforced composites. The CNTs are treated as effective elastic fibers. For both aligned and random oriented cases, CNTs are randomly distributed in a cuboid matrix. Ideal interfacial condition is considered between the CNTs and matrix. The effective modulus of the composite is evaluated using the mean stress and mean strain of the matrix. The numerical results are compared with experimental data published in the literature. The effects of micro-structural parameters, namely the CNT fiber aspect ratio, volume fraction and orientation on the effective elastic modulus and interfacial stress fields are studied. Besides the elastic property, the thermal property and electric property of the CNT composites have also been simulated using the FM-BEM. For the simulation of thermal property, the CNTs are treated as straight fibers with thermal conductivity of an infinite value, and for the simulation of electric property, CNTs are treated as straight fibers with electric conductivity of an infinite value. The effective thermal conductivity and effective electric conductivity are evaluated and compared with experimental data published in literature. The numerical tests clearly demonstrate potential of the FM-BEM for large scale solutions of such composites. Based on the present work, future investigations will be carried out in the modeling with more accurate interface conditions of CNT composites. More detailed investigation on the effects of micro-structure of CNT composites, including the thermal contact and electrical contact between the CNTs, will be carried out as well.