  Fragmentation can be observed in nature and in everyday life on a wide range
of length scales and for all kinds of technical applications. Most studies on
dynamic failure focus on the behaviour of bulk systems in one, two and three
dimensions under impact and explosive loading, showing universal power law
behaviour of fragment size distribution. However, hardly any studies have been
devoted to fragmentation of shells. We present a detailed experimental and
theoretical study on the fragmentation of closed thin shells of various
materials, due to an excess load inside the system and impact with a hard wall.
Characteristic fragmentation mechanisms are identified by means of a high speed
camera and fragment shapes and mass distributions are evaluated. Theoretical
rationalisation is given by means of stochastic break-up models and large-scale
discrete element simulations with spherical shell systems under different
extreme loading situations. By this we ex-plain fragment shapes and
distributions and prove a power law for the fragment mass distribution.
Satisfactory agreement between experimental findings and nu-merical predictions
of the exponents of the power laws for the fragment shapes is obtained.
