Behavior of laminated glass under the combined effect of blast wave and the impact of fragments

In the event of an accidental explosion or a terrorist attack using a shrapnel bomb, significant damage is caused due to the impact of fragments which are generated during the explosion and hurled against structures at high speed. Fragments in contact with or very near a detonated explosive charge can be accelerated to very high velocities and can pose a threat to nearby personnel and infrastructure. A “nail-bomb” (Figure 1.a) is an example of Improvised Explosive Devices (IED) containing nails, steel ball bearings, needles and other metallic fragments (Figure 1.b) resulting in major injuries and human casualties as well as localized and overall structural damage (Figure 1.c). A possible solution to protect building’s facades and occupants within a building against this threat is the use of laminated glass (LG) (Figure 2) where the glass is combined with a transparent polymer film to which the glass shards or fragments adhere upon fracture. Standards for separate ballistics and explosive testing of laminated glass and other protective materials are available and widely used. Standards considering a more realistic combined action of blast wave and fragments do not exist.