<s>
The	O
dynamic	B-Algorithm
design	I-Algorithm
analysis	I-Algorithm
method	I-Algorithm
(	O
DDAM	B-Algorithm
)	O
is	O
a	O
US	O
Navy-developed	O
analytical	O
procedure	O
for	O
evaluating	O
the	O
design	O
of	O
equipment	O
subject	O
to	O
dynamic	O
loading	O
caused	O
by	O
underwater	O
explosions	O
(	O
UNDEX	O
)	O
.	O
</s>
<s>
The	O
analytical	O
process	O
simulates	O
the	O
interaction	O
between	O
the	O
shock-loaded	O
component	O
and	O
its	O
fixed	O
structure	O
,	O
and	O
it	O
is	O
a	O
standard	O
naval	O
engineering	O
procedure	O
for	O
shipboard	O
structural	B-Algorithm
dynamics	I-Algorithm
.	O
</s>
<s>
All	O
mission-essential	O
equipment	O
on	O
board	O
military	O
surface	O
ships	O
and	O
submarines	O
must	O
be	O
qualified	O
for	O
underwater	O
shock	O
loads	O
caused	O
by	O
depth	B-Device
charges	I-Device
,	O
naval	O
mines	O
,	O
missiles	O
,	O
and	O
torpedoes	O
.	O
</s>
<s>
With	O
the	O
advances	O
in	O
computer	B-Application
simulation	I-Application
and	O
modeling	O
capabilities	O
,	O
it	O
is	O
now	O
possible	O
to	O
simulate	O
a	O
vessel	O
's	O
response	O
to	O
an	O
underwater	O
explosion	O
and	O
to	O
identify	O
potential	O
problems	O
or	O
failures	O
without	O
extensive	O
field	O
testing	O
.	O
</s>
<s>
By	O
using	O
DDAM	B-Algorithm
analytical	O
techniques	O
,	O
money	O
and	O
time	O
are	O
saved	O
.	O
</s>
<s>
The	O
DDAM	B-Algorithm
simulates	O
the	O
interaction	O
between	O
the	O
shock-loaded	O
component	O
and	O
its	O
fixed	O
structure	O
as	O
the	O
free	O
motion	O
of	O
a	O
naval	O
vessel	O
in	O
water	O
produces	O
a	O
higher	O
shock	O
spectrum	O
than	O
a	O
heavy	O
structure	O
would	O
when	O
mounted	O
to	O
a	O
terrestrial	O
surface	O
.	O
</s>
<s>
The	O
DDAM	B-Algorithm
takes	O
interaction	O
into	O
account	O
in	O
relation	O
to	O
the	O
mass	O
of	O
the	O
equipment	O
,	O
its	O
mounting	O
location	O
,	O
and	O
the	O
orientation	O
of	O
the	O
equipment	O
on	O
the	O
vessel	O
.	O
</s>
<s>
Engineers	O
use	O
finite	B-Application
element	I-Application
method	I-Application
analysis	O
software	O
to	O
verify	O
designs	O
using	O
DDAM	B-Algorithm
computer	B-Application
simulations	I-Application
that	O
model	O
the	O
known	O
characteristics	O
of	O
underwater	O
explosion	O
phenomena	O
as	O
well	O
as	O
the	O
surface	O
ship	O
or	O
submarine	O
body	O
responses	O
to	O
shock	O
loading	O
and	O
application	O
of	O
a	O
shock	O
spectra	O
in	O
order	O
to	O
apply	O
the	O
appropriate	O
shock	O
responses	O
at	O
the	O
mountings	O
of	O
shipboard	O
equipment	O
(	O
e.g.	O
,	O
masts	O
,	O
propulsion	O
shafts	O
,	O
rudders	O
,	O
rudderstocks	O
,	O
bearings	O
,	O
exhaust	O
uptakes	O
and	O
other	O
critical	O
structures	O
)	O
due	O
to	O
underwater	O
explosions	O
.	O
</s>
<s>
The	O
analytical	O
process	O
is	O
described	O
in	O
NAVSEA	O
0908-LP-000-3010	O
,	O
Shock	O
Design	O
Criteria	O
for	O
Surface	O
Ships	O
which	O
provides	O
technical	O
criteria	O
for	O
shock	O
design	O
calculations	O
,	O
and	O
provides	O
general	O
background	O
and	O
educational	O
material	O
concerning	O
application	O
of	O
the	O
DDAM	B-Algorithm
.	O
</s>
<s>
A	O
number	O
of	O
commercially	O
available	O
computer	B-Application
modeling	I-Application
and	O
simulation	O
programs	O
are	O
available	O
to	O
assist	O
in	O
this	O
task	O
.	O
</s>
<s>
After	O
the	O
analyst	O
performs	O
a	O
natural	O
frequency	O
analysis	O
to	O
determine	O
the	O
mode	O
shapes	O
and	O
natural	O
frequencies	O
,	O
the	O
DDAM	B-Algorithm
process	O
then	O
uses	O
an	O
input	O
spectrum	O
of	O
shock	O
design	O
values	O
(	O
i.e.	O
,	O
displacements	O
or	O
accelerations	O
)	O
based	O
on	O
data	O
from	O
a	O
series	O
of	O
unclassified	O
Naval	O
Research	O
Laboratory	O
reports	O
(	O
primarily	O
MR-1396	O
,	O
Design	O
Values	O
for	O
Shock	O
Design	O
of	O
Shipboard	O
Equipment	O
and	O
FR-6267	O
,	O
Background	O
for	O
Mechanical	O
Shock	O
Design	O
of	O
Ships	O
)	O
.	O
</s>
<s>
Compliance	O
standards	O
for	O
DDAM	B-Algorithm
simulation	O
and	O
analysis	O
software	O
are	O
maintained	O
by	O
the	O
Naval	O
Sea	O
Systems	O
Command	O
(	O
NAVSEA	O
)	O
.	O
</s>
<s>
The	O
Naval	O
Sea	O
Systems	O
Command	O
(	O
NAVSEA	O
)	O
established	O
a	O
standardized	O
format	O
to	O
describe	O
the	O
content	O
and	O
formats	O
for	O
publishing	O
results	O
of	O
the	O
DDAM	B-Algorithm
analyses	O
and	O
technical	O
reports	O
.	O
</s>
<s>
The	O
DIDs	O
for	O
DDAM	B-Algorithm
activities	O
are	O
the	O
Analysis	O
Report	O
,	O
Dynamic	O
Shock	O
,	O
Mathematical	O
Model	O
Report	O
,	O
Dynamic	O
Shock	O
Analysis	O
,	O
and	O
Dynamic	O
Shock	O
Analysis	O
Extension	O
Request''	O
.	O
</s>
