Ricerc@Sapienza

Thanks to the unique flexural properties, sandwich composites are considered as irreplaceable structures in many industrial fields, but their susceptibility to impact events is still a considerable drawback that undermines their structural integrity determining a reduction of their load-bearing capabilities. Considering that the core material plays the major role to distance the skins, the knowledge of its multiple-impacts response becomes a key design parameter in order to ensure a long-term stability to the structure. In view of this, the present work addresses the multiple-impacts behavior in dynamic compression and puncture impact conditions of bio-based agglomerated cork cores taking into account the effect of density and providing a meaningful comparison with more traditional petroleum-based foams. Despite the inherently higher mechanical properties of the PVC (polyvinyl chloride) foams, agglomerated cork demonstrated to provide a higher dimensional stability to the structure after repeated impacts thanks to its unique microstructure. With a reduction lower than 25% of its initial height after 10 impacts, agglomerated cork NL25 proved to be an exceptional alternative to the common HP130 foam, which undergoes a halving of its initial height after only 3 impacts, to obtain a more eco-friendly and performing sandwich composite.