Carbon nanotube (CNT) is considered as a new generation of material possessing superior mechanical, thermal and electrical properties. Recent investigations [1,2] have shown that CNTs when aligned perpendiculars to cracks are able to slow down the crack growth by bridging up the crack faces. In this research a multi-scale analysis and finite element (FE) method are proposed to study the interaction of nanotubes and matrix at the nano-scale near a crack tip. Opening mode for bridging condition (SWCNT is orthogonal to crack and crack is in middle of representative volume element RVE) with epoxy/SWCNT 0.1% wt is considered. The effect of the chirality of armchair and zig-zag single walled carbon nanotubes (SWCNTs) in a polymer matrix in presence of van der Waals (vdW) interaction as interphase region on the fracture behavior were studied. It was found that the chirality has a significant effect on stress intensity factor of nanocomposites.
