Imperfections in glass formed during manufacture or subsequent transportation can weaken bottles, creating a hazard by causing them to fail at lower pressure. When soda glass bottles are pressurized to fracture, the crack density in the broken glass and the fracture pressure are highly correlated. A higher fracture pressure yields a higher crack density as a result of the greater amount of stored energy released on fracture. Thus, after failure it is possible to estimate the pressure to which a bottle was subjected by analysing the glass fragments. The crack patterns and density agree with analytical models for crack branching in brittle materials under stress. The crack patterns of pressurized bottles subjected to impact are also observed, and a minimum side impact velocity of 2.0m/s for rupture of pressurised commercial soda glass bottles is determined.
