From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: alt.engr.explosives
Subject: Re: Shock wave
Date: 18 Sep 1995 20:09:39 GMT
Organization: Consulting Chemist

In article <43jqpi$mh2@waage.rz.uni-ulm.de>, s_gleich@cellar.rz.uni-ulm.de 
(Bernhard Gleich) says:

>Is the shock wave in a detonation needed for the shattering power? In
>other words: Assume igniting an explosive in an infinite strength
>container (thermally insulated). Wait one moment. Suddenly remove the
>container. Compare the effects of this kind of explosion with the
>detonation of the same explosive (e.g. lead block).
>
>Which kinds of tests would give similar results, which would be much
>different? I assume the lead block would give quite similar results,
>but shaped charges would not work as well. 

The shaped charge would probably yield a faster jet using
your hypothetical container, because the instantaneous pressure 
would be applied over the length of the cone as though you had
used an explosive lens in a conventional shaped charge. 

A regular charge might give a higher transitory pressure because
of the reaction in the compressed gas immediately behind the
shock front, but I would guess the preconfined charge would still
outperform the conventional charge in compressing a lead cylinder 
because of the additional time that pressure would be applied to 
the target while the corresponding conventional detonation wave 
was traveling toward the target. It might be noted that one gets 
pretty good compression from a conventional charge even when it 
is fired backwards, i.e. with the detonation wave travelling away 
from the target, which can be related in some respects to your
hypothetical no-shockwave scenario except that the impulse would
be less in the unconfined backwards-firing charge.

Rather than thinking of shockwaves as generating pressure, it 
might be better to think of them as being products or
manifestations of pressure.

Jerry