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Numerical modelling of scaled centre-notched [45/90/−45/0] 4s carbon/epoxy laminates was carried out. The in-plane dimensions of the models were scaled up by a factor of up to 16. A Finite Element (FE) method using the explicit code LS-Dyna was applied to study the progressive damage development at the notch tips. Cohesive interface elements were used to simulate splits within plies and delaminations between plies. A failure criterion based on Weibull statistics was used to account for fibre failure. There is a good correlation between the numerical and experimental results, and the scaling trend can be explained in terms of the growth of the notch tip damage zone. The modelling gives new insights into the damage development in the quasi-isotropic laminates with sharp cracks, specifically, the growth of splits, delaminations and local fibre breakage. [ABSTRACT FROM AUTHOR]

An experimental investigation into size effects in notched [45/90/−45/0]4s carbon/epoxy laminates is carried out. The in-plane dimensions of the quasi-isotropic laminates are scaled up by a factor of up to 8. Larger Scale 16 specimens with only their width and notch length being doubled were also tested as a further comparison. Interrupted tests and X-ray Computed Tomography (CT) scanning are carried out to study the damage at the crack tips. Sharp centre-notched tensile tests are compared to open-hole tests of the same notch length (hole diameter), material and stacking sequence. A similar strength reduction scaling trend is found for both configurations at the small sizes, except with higher tensile strength for the centre-notched specimens than the open-hole specimens. However, there is a cross-over point when the sizes increase, with the sharp notched results approaching an asymptote based on Linear Elastic Fracture Mechanics (LEFM), and the open hole results approaching an asymptote based on Weibull theory. [ABSTRACT FROM AUTHOR]