Stress transfer efficiency in aligned multi-wall carbon nanotubes sheet/epoxy composites

Stress transfer efficiency for 60 walls multi-walled carbon nanotube (MWNT) was calculated by the shear-lag theory. The results indicated that stress transfer between walls is insufficient at several tens of nanometer from the end; however stress converged to the same value for adequate length. Effective young’s modulus was also calculated and indicated that MWNT can be treated as short fiber for over 20 μm length (Aspect ratio >400). The results implied that interfacial slippage or debonding area exists at the end of the MWNTs. Calculated results, including the alignment and interfacial strength between carbon nanotube (CNTs) and polymer, were compared to the mechanical properties of aligned carbon nanotube sheet/epoxy composite to evaluate the validity of reinforcement mechanism of MWNT. The experimental results were able to be explained reasonably by the numerical results.