Design of honeycomb structures for naval applications

During normal sailing and operation conditions, naval structures are subjected to impact events deriving from several sources, such as collisions with docks, with floating objects or with on board equipment. As a result, the naval sector is interested in the development of impact protective structures, whose design needs also to deal with weight constraints, which are of primary importance for marine applications. The aim of the present work is to suggest aluminium honeycomb sandwich structures as lightweight energy absorbers to protect racing marine structures from impacts. Several honeycomb structures with different geometrical characteristics were considered. In addition, different honeycomb sandwich panels were combined in order to obtain multi-layer structures to improve energy absorption properties and to control the collapse sequence. Low-velocity impact tests were performed and the results allowed the identification of failure modes and energy absorption performance during local impact events. A theoretical model was applied to identify the parameters involved in impact response of honeycomb sandwich structures. A comparison of energy absorption efficiency of other structures was performed. The obtained results highlighted that the investigated structures may have promising applications for impact protection in the naval field.