Failure of Impact Damaged Foam Core Sandwich Beams

The scope of this paper is to investigate the structural integrity of sandwich beams subjected to various load cases after local impact. The studied impact damages can be characterised as core indentation and face/core interface damage while the faces are virtually unaffected by the impact. At subsequent loading different types of post impact failure occur, depending on the size of the impact damages and the applied load. Sandwich beams are impacted using two different impact energies and the resulting damage is inspected and measured. The measurements are used to characterise the damage and as input for analytical and finite element models in order to predict post impact failure in various load cases. The impact damages are modelled as face/core interface cracks but the approach is found to be too rough to achieve full agreement with experiments. It is concluded that the damaged face/core interface is not entirely separated but some bridging remains between the surfaces.