Folks . . . 
not to beat this one to death , but thought I would present some other ideas.
If you consider modern * earthquake * resistant designs of buildings , the main
goal is to keep the building from transmitting the energy throughout it's frame.

The designs , allow a portion of the energy to be absorbed at points that prevent
the total energy from making it to any one section. An analogy would be trying
to drive a nail into a board , using a hammer that has a * limp * rubber handle .
All of the componants are the same . . . . except you never get the total energy to
the head of the hammer , a great deal of it is consumed in the flexing of the handle.

While some buildings ( older ones ) are being braced and fitted with tie-rods,
etc. most of this effort is to keep them from sliding into the street or bowing out
and caving in.  The point here is anything that is made too rigid , is going to have
a problem with transmitting the energy ( vibration / shock ) throughout it's structure.

PCB 's  ( like modern buildings ) can be designed to twist , flex , and bend in the
presence of destructive energy.  Also , if the PCB must be made rigid ( as usual ) ,
the option would be to * isolate * the assembly .  This can be done with mounting 
post that are designed  to provide a rigid enough mounting , yet using a honeycomb
or simular design can * isolate * the entire PCB from the majority of the vibrations.

For extreme conditions . . . it is not out of the question to * suspend * the PCB using
a spring at each corner of the PCB . . . . this technique eliminates almost all vibration.
Springs can be designed from non-conductive materials too , if required .

I'm still wading through some files to locate the flex and additive process (dispensed )
information , when found I'll post it .  By-the-way . . . the flex-circuits can be made using
foil too ( as seen in many flat harnesses that have substantial movement ) , one of these
probably connects your floppy or hard-drive r/w head to the amp.  Anyway , these flex
designs can be created in double-sided / multi-layer , you name it . . . . . . the aircraft
industry ( i.e. fighters / Mc Donnell Douglas ) uses flex designs to stand up to the high
vibration and thermal stress problems they encounter .

Regards . . . 
                        Steve 
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 PROTOBYTE INC.                     www.protobyte.com
14208 Zachary Dr.
Liberty, MO 64068                  Design and Prototyping

Email: info@protobyte.com
Phone: (816)-792-0235

Steve Kelley / Owner
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