Novel sandwich panel with metallic millitube grid stiffened polymer core for impact mitigation

• A new sandwich with metallic millitube grid stiffened polymer core is investigated.
• Low velocity impact test and ballistic impact test were conducted.
• The sandwich exhibits remarkable impact tolerance.
• It may be a viable alternative for protective structures.

Sandwich construction has been extensively used in various fields. However, sandwich panels have not been fully exploited in critical structural applications due to damage tolerance and safety concern. A major problem of sandwich panels is the vulnerability to impact loading, which can lead to a sudden loss of structural integrity and cause catastrophic consequences. In order to improve the energy absorption of sandwich panel under impact loading, a new sandwich core is proposed which is a hybrid core consisting of hollow metallic millitube grid stiffened polymer matrix. The objective of this study is to characterize its impact performances. Quasi-static low velocity impact test and ballistic impact test demonstrate that the new sandwich panel may be considered as a promising option for critical structural applications featured by multiple impact tolerance.