Peridynamic 3D models of nanofiber networks and carbon nanotube-reinforced composites

Here we employ a reformulation of the continuum mechanics theory, the peridynamic formulation (PF) in an integral form that, at the discretized level, resembles molecular dynamics (MD). The peridynamic theory is based on a continuum formulation and can capture nucleation and propagation of defects and discontinuities without ad-hoc assumptions or special treatments needed by classical continuum theory. We analyze nanofiber networks and CNT-reinforced polymer composites. We treat all crossovers contacts between fibers as perfect bonds. The use of repulsive short-range forces eliminates the need for complex contact detection algorithms. We generate the fibers as 3D curves with random orientation, with or without preferred directionality. We use an object-oriented code written in Fortran 90/95 to define the geometrical entities. The PF can capture the deformation and complex fracture behavior in fully 3D dynamic simulations. van der Waals forces are included in these calculations. The strength of the bonds between the polymer chains and the CNTs, as well as among the chains, is controllable.