This work simulates numerically Double Cantilever Beam and End Notched Flexure experiments on Carbon Fibre Epoxy Resin specimens that have been performed by some of the authors in a previous work. Specimens have been nanomodified by interleaving plies with a layer of electrospun nanofibres in the delaminated interface. Eight different configurations of nanofibres have been used as interleave, for a total of 9 configurations (8 nanomodified plus the virgin one) to be simulated for both kind of tests to identify the cohesive zone parameters corresponding to the effect of nanofibre diameter, nanolayer thickness and nanofibre orientation on the delamination behaviour of the composite. Results showed that a bilinear damage law is necessary for almost all nanomodified configurations, and presented a clear relationship between nanomat layer parameters and the cohesive energy of the interface

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Purpose – In this work, the cohesive zone model (CZM) developed by some of the authors to simulate the propagation of fatigue defects in two dimensions is extended in order to simulate the propagation of defects in 3D. The paper aims to discuss this issue. Design/methodology/approach – The procedure has been implemented in the finite element (FE) solver (Abaqus) by programming the appropriate software-embedded subroutines. Part of the procedure is devoted to the calculation of the rate of energy release per unit, G, necessary to know the growth of the defect. Findings – The model was tested on different joint geometries, with different load conditions (pure mode I, mode II pure, mixed mode I/II) and the results of the analysis were compared with analytical solutions or virtual crack closure technique (VCCT). Originality/value – The possibility to simulate the growth of a crack without any re-meshing requirements and the relatively easy possibility to manipulate the constitutive law of the cohesive elements makes the CZM attractive also for the fatigue crack growth simulation. However, differently from VCCT, three-dimensional fatigue de-bonding/delamination with CZM is not yet state-of-art in FE softwares.