Influence of constitutive metal model on the numerical prediction of the impact behaviour of titanium-based Fibre Metal Laminates

Abstract

Due to increasing needs of the aerospace industry for light and durable materials, FMLs – particularly titanium-based – are constantly being developed. Attempts at numerical prediction of the impact behaviour of FMLs have been made in numerous studies. None of these studies, however, considered the influence of the applied constitutive models of studied metals, despite the major role of metals in energy absorption. To determine present this relation, two models of elastic damage, i.e. ductile and Johnson-Cook damage models were used in the FEA performed by the authors. A series of simulations were conducted in order to determine the impact behaviour of hybrid titanium-carbon laminates. Numerical results were compared with experimental findings in a multi-criteria analysis. The secondary goal of the study was to compare both models in terms of their efficiency. Both models predicted impact behaviour and damage with a reasonable accuracy, recreating the trends observed in the experiment. However, the effectiveness of the models changes with impact energy. The ductile damage model showed higher agreement for 2.5 J and 5 J. For higher energies, where high strain rates were expected, the results obtained with the Johnson-Cook damage model showed a lower mismatch than those obtained with the ductile damage model.