Theoretical and finite element approaches to model the phenomenon of high-velocity impact on GFRP plates

Abstract

New energy-based theoretical models that predict the ballistic behaviour of thin and thick woven composite laminates are presented. These models are formulated for high-velocity impacts, where the boundary conditions do not play a relevant role. This can be assumed as the local structural behaviour is responsible for the ballistic performance. A non-dimensional formulation is used to analyse the influence of material properties and geometrical parameters in the ballistic response of the laminate. The models are physically-based on the energy contribution of different energy-absorption mechanisms. Moreover, a 3D finite element model is also developed by means of  a continuum damage mechanics model that takes into account the different failure mechanisms described in the theoretical models to simulate the performance of the laminate under high-velocity impacts and to validate the hypotheses of the theoretical models.  A comparison between FE and theoretical models is performed by means of energy absorption mechanisms. The predictive capability of the proposed models is verified against experimental results, which were originally conducted in this work. The results obtained show the dependencies between the ballistic response and the non-dimensional physical parameters of the model. Furthermore, the proposed models can be used to see the relative importance of the different energy-absorption mechanisms involved and the comparison of these mechanisms between the theoretical and the FE models can reflect the different roles played by them, depending on the material properties and geometrical characteristics of the laminate. These results highlight the relevance of the in-plane and out-of-plane energy-absorption mechanisms, which rule the penetration process depending on the plate thickness.