Fig. 14-right shows the influence of the base shape on the strain
history in the bottlewall at the position 50 mmfrom the base. It can
be seen that the loading rate is lower for the bottle with the originally
manufactured curved base. This is caused by a gradual water
stoppage due to deformation of the base as opposed to a sudden
stop in the case of a bottle having a flat and rigid base. The shape of
the first loading pulse is triangular, and slightly smaller in magnitude
than in the case with a flat and rigid base. In addition,
subsequent oscillations are much shorter and smaller in magnitude,
since the bottle has bounced. Similar behaviour is observed in
the experiments (Fig. 9).