Influence of non-bonded interphase on crack driving force in carbon nanotube reinforced polymer

► A non-linear multi-scale finite element mode is developed to study fracture properties of carbon nanotube reinforced polymer. ► It is shown that non-bonded interphase region plays an important role on hindering crack growth. ► It is proven that lattice structure of CNT has to be taken into account in modeling process and it cannot be neglected.