MODELLING OF DAMAGE IN COMPOSITES USING SMOOTH PARTICLE HYDRODYNAMICS METHOD

This paper aims at the development and implementation of an algorithm for the treatment of damage and fracture in smooth particle hydrodynamic (SPH) method, where free surface, crack opening, including its propagation and branching is modelled by weakening the interparticle interactions combined with the visibility criterion. The model is consistent with classical continuum damage mechanics approach, but does not use an effective stress concept. It is a difficult task to model fracture leading to fragmentation in materials subjected to high-strain rates using continuum mechanics. Meshless methods such as SPH are well suited to be applied to fracture mechanics problems, since they are not prone to the problems associated with mesh tangling. The SPH momentum equation can be rearranged and expressed in terms of a particleparticle interaction area. Damage acts to reduce this area, which is ultimately set to zero, indicating material fracture. The first implementation of the model makes use of Cochran-Banner damage parameter evolution and incorporates a multiple bond break criterion for each neighbourhood of particles. This model implementation was verified in simulation of the onedimensional and three-dimensional flyer plate impact tests, where the results were compared to experimental data. The test showed that the model can recreate the phenomena associated with uniaxial spall to a high degree of accuracy. The model was then applied to orthotropic material formulation, combined with the failure modes typical for composites, and used for simulation of the hard projectile impact on composite target.