  The use of glass for pharmaceutical new applications such as high-technology
drugs, requires the strictest container inertness. A common theme of paramount
importance in glass container integrity preservation is the detailed mechanism
driving the sudden failure due the crack propagation. Using a combination of
Discrete Element Method (DEM) and Finite Element Method (FEM), a stress map for
glass cartridges packed into an accumulation table and transported by a
conveyor belt at a fixed velocity is obtained under realistic conditions. The
DEM calculation provides a full description of the dynamics of the cartridges,
as approximated by an equivalent sphere, as well as the statistics of the
multiple collisions. The FEM calculation exploits this input to provide the
maximum principal stress of different pairs as a function of time. Our analysis
shows that, during their transportation on the conveyor belt, the cartridges
are subject to several shocks of varying intensities. Under these conditions, a
crack may originate inside the cartridge in the area of maximal tensile stress,
and propagate outward. Estimated stresses are found in good agreement with real
systems.

Soft Condensed Matter;Statistical Mechanics