Fragment impact on concrete slabs: An experimental and numerical study

Fragments, for instance generated by a blast or vehicle collision, can impact a nearby structure with significant damage potential. Such fragments can have varying sizes, shapes and velocities. It is thus important to understand how these fragments will influence the structure, and how fragment size and shape affect the damage potential in various protective structures. In this study, we fired three different projectile types to study fragment impact on 50 mm thick plain C35 concrete slabs. We used material tests and literature data to calibrate a concrete constitutive relation for finite element modelling in LS-DYNA. An axisymmetric numerical model reproduced the results to a satisfactory degree, both in terms of ballistic limit velocities, residual projectile velocity and mass loss. The results showed that despite having similar ballistic limit velocities, the three projectiles gave significantly different response for higher initial velocities.