Numerical analyses of low velocity impacts on composite. Advanced modelling techniques.

Abstract

Due to the extreme increase in computational power over the last years, numerical analyses are gaining more success in designing composite structures and components, taking into consideration complicated failure mechanisms. One crucial aspect is low velocity impact. It can produce devastating damage that can lead to premature failure of the component/structure. However, modelling the three-dimensional impact damage and its consequences is still a challenge. This is because material properties, failure criteria, properties after initial failure, and numerical techniques are still not well established, especially for the through thickness properties. As a consequence, industry must perform costly full-scale tests to improve the design and eventually to prove its fitness for purpose. In this paper the most advanced features currently available in FE analysis (Abaqus/Explicit) have been used to predict the behaviour of a composite structure under low velocity impact. A low velocity impact event on a flat composite plate has been evaluated. The plate has been modelled using solid elements for each composite layer and a user defined material model with a modified Puck failure criterion was implemented. The intralayer damages (fibre breaking, matrix failure) are evaluated. Between each layer, cohesive elements have been placed to model the interlayer damage (delamination). Failure initiation and properties of damaged/degraded materials are modelled. The influences of the different parameters, mesh dimensions, element types and failure criteria on the numerical results are reported. The numerical results have been compared with real experimental data from literature.