There is an increasing demand in developing structures that can withstand extreme loading including shocks and projectile impact that can be generated due to explosions and blast. Desirable mechanical performance of metal sandwich panels compared to solid plates of same mass combined with their multifunctional advantages makes them a unique candidate for development of low weight multifunctional structural systems. In this work detailed finite element simulations were carried out to study response and failure of metallic sandwich panels with square honeycomb core subjected to multiple impulsive pressure and combined shock/projectile loading and results were compared with ones from counterpart solid plate. The resistance of panels to these loading is quantified by the maximum transverse deflection of bottom face sheet and core crushing strain at mid-span of the panel as a function of shocks peak over-pressure or projectile velocity. An empirical relation was proposed to predict deflection of panel subjected to two consecutive shock loading. Failure maps were constructed to show different fracture modes in panel with different core relative density and shock peak pressure or projectile velocity. Results show that sandwich panels can hold their functionality and carry more load even after impinged by a intensive shock and can be used as a proper structural component in industries that subsequent explosions resulted from initial shock can happen for example in gas and oil fields and pipeline networks.