Blast wave interaction with window glass

Recent events in Chelyabinsk (meteorite), Beirut (ammonium nitrate explosion), and Ukraine (war) have all resulted in multiple injuries and deaths due to windows broken by blast waves. We investigate how soda-lime window glass shatters after impact of a shock wave. As the glass shatters, the distribution of fragment sizes is strongly non-uniform, with the smallest fragments forming near the perimeter where the glass is mounted. Moreover, we find that the glass does not break immediately upon shock arrival, and a reflected shock wave is produced before the glass breaks. We present flow visualization and pressure traces for glass samples tested at Mach numbers 1.45, 1.6 and 2.0. The glass samples are all 4” by 4” in size. We also investigate the possibility of making the window glass more blast-resistant using low-tech mitigation strategies (for example, applying a sodium silicate water solution to the sample).