Dynamic responses of ultralight all-metallic honeycomb sandwich panels under fully confined blast loading

Fatal threats of fully confined blasts to surface battleships must be minimized to avoid catastrophic failure such as ship sinking. In the present study, for enhanced blast resistance, ultralight all-metallic sandwich panels with square honeycomb cores are proposed as an alternative to traditional metallic plates for ship construction. A combined experimental and numerical approach is employed to investigate the dynamic responses of fully-clamped sandwich panel subjected to fully confined blast loading and compare its blast resistance to that of its monolithic counterpart having equal mass. To explore the underlying physical mechanisms, finite element simulations with the Coupled Eulerian-Lagrangian (CEL) approach are performed. The simulation results are validated against experimental measurements for both sandwich and monolithic target plates, with good agreement achieved. It is demonstrated that, with the pressure versus time history on target plate featured by multiple reflected overpressures and a long-duration quasi-static phase with considerably lower pressure amplitude, the proposed sandwich panel exhibits a considerably higher blast resistance than its monolithic counterpart of equal areal density placed at the same standoff distance, due mainly to its consumption of impact energy via global out-of-plane bending, in-plane stretching, and localized core crushing. Results of this study are helpful for designing novel lightweight protection structures with enhanced blast resistance for ship construction.