Impact fragments from honeycomb sandwich panels

Sandwich panels are currently employed in space structure thanks to their light weight, good mechanical resistance, and enhanced capability to protect internal component from space debris. In case of impacts, sandwich panels may fragment differently from simple plates in terms of number and shape of generated debris. The effect of this different behaviour on satellites break-ups is currently under scrutiny, as existing fragmentation models are mostly based on data on aluminium plates. In this context, the University of Padova performed a set of impact experiments on different materials employed in the space sector. In particular, the test campaign focused on honeycomb sandwich panels with aluminium and carbon-fibre reinforced panels (CFRPs) skins. For all tests the generated fragments were collected, weighed, and sifted in size classes; their shape and size were acquired through image acquisition. In this paper the main results of the test campaign are presented, in terms of fragments characteristic length distributions and shape fragments distributions. Results show that at the same impact conditions the number of fragments generated by panels with CFRP skins is larger than the ones generated by panels with aluminium skin; with respect to the shape, it was noted that a large fraction of the fragments generated by panels with CFRP skins showed needle-like shapes.