Marine
Martec Limited has considerable
expertise in modeling the response of vessels to
underwater explosions, and has developed tools which
are being used to support experimental programs sponsored
by the Canadian Department of National Defence. This
expertise has been used to develop specialized models
for both predicting pressure loading due to underwater
explosions and the response of global ship models
to these loads. Of particular concern in recent years
are asymmetric threats, where a relatively low-tech
high explosive is deployed against a high-value military
asset such as the attack on the USS Cole in 2000.
Predicting the effects of underwater explosions is
challenging as the target can be subjected to different
types of loading depending on the device size, how
close it is to the target, and the depth of the water
in the immediate vicinity. A typical underwater explosive
will generate a strong shock wave that can disable
critical equipment due to vibration response. It may
also generate effects that can damage the ship hull.
Following the initial shock wave, the high-pressure
gases formed by the explosive combustion expand to
form a large bubble. After a certain critical size
is reached the bubble collapses and restarts the expansion.
If there is a solid shape in the vicinity of the bubble,
the bubble will collapse as a jet of high velocity
water that can produce significant local damage, possibly
breaching the ship hull.
References:
1. R.A. Link, L. Donahue, J.E. Slater, "Numerical
Simulation of the Loading and Response of Flat Plate
Targets Subjected to Close-Proximity Underwater Explosions",
75th Shock and Vibration Symposium, October 2004,
Virginia Beach, VA.
2. R.A. Link, R.C. Ripley, M. Norwood, L. Donahue,
T. Josey, J. Slater, ”Analysis of the Loading
and Response of Flat Plate Targets Subjected to Close-Proximity
Underwater Explosions”, 74th Shock and Vibration
Symposium, October 2003, San Diego, CA.
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