5. Conclusions
The analysis of experimental results demonstrates that there is
a pressurewave travelling through fluid-filled containers subjected
to the base drop impact. This is also supported by a sequence of
a video-recorded drop impact test on RT6 containers, shown in
Fig. 17. These containers have a rectangular cross-section area, and
thus more pronounced and noticable deformation. The presence of
a pressure wave travelling can be seen from the ripples on the
container wall: the container deforms progressively in time from
the base towards the top due to the internal pressure wave. As the
pressure wave reaches the top, the container wall is fully stressed
by the internal pressure and the crack starts to propagate (image
19–20).
The period of the main oscillation in the pressure/strain histories,
and its magnitude are well predicted by waterhammer theory.
Maximum pressure magnitude follows a parabolic relationship to
drop height. Natural oscillations are present in all results, and their
period is in agreement with Eq. (7). The shape of the container base
significantly affects the pressure produced by the impact. This is
mainly due to the base deformation caused by the impact. The
water inside the container is gradually stopped, thus reducing the
pressure (strain) rate and magnitude.
Results obtained from the two-system FSI simulations are found
to be in good agreement with theoretical and experimental findings.
It is clearly demonstrated that the pressure wave produced by