The article presents sandwich panels subjected to blast wave impact and accelerated fragments. The research discusses results obtained from original experimental setups that fill a gap in the area of investigation of the mechanical response of sandwich panels used in civil engineering applications under accidental design situations such as blast wave impact and/or fragment penetration. In field experiments, a high-speed camera was used to record both the fragment trajectory and the deflection of the sandwich panel. The authors proposed the equivalent static load for both the global analysis of the sandwich panel and the calibration of the numerical model. In FE modelling, CONWEP algorithm was used to simulate blast wave impact, and ductile damage model material to allow perforation of the sandwich panel faces. The convergence of mesh size was analyzed. For the validated numerical model, an evaluation of the effect of the size of the fragment (diameter/mass) on the outlet velocity and the size of the inlet and outlet holes was carried out.