isolation and shock mounting. This is one of those topics that
involves considerable art as well as science. To suggest some talking
points, you might first consider isolating the module rather than the
stairway. It makes a lot more sense to add shock mounts to the piece
which shouldn't feel vibration because the idea is not to 'soak up'
the transmitted shock rather to make the module less sensitive to it.
The materials involved won't be the usual stuff you use to cushion
structures, but probably some of the silicones or maybe urethanes.
The isolators themselves need to be matched to the dynamic response
of the module, so it's not just a matter of selecting a material--
there's need for doing some response calculations. You migth get some
custom help from manufacturers, but these guys are normally in the
business of selling isolators, not doing shock and vibration
analysis; if you docontact a supplier be ready with some weights,
frequencies and amplitudes.
On Sep 14, 2009, at 5:41 PM, Drew Morris wrote:
> I have a project where we need to attach a stair to a structural
> steel frame supporting a module that contains sensative monitoring
> equipment. The owner wants to minimize the vibrations coming from
> people walking up the stairs so we need to put some sort of
> elastomeric vibration pads between the stairs and the frame. I
> need to orientate the pads so that they can support the gravity
> loads in shear, not in bearing as is typical for heavy machinery.
> Also, this project is in the polar reagions, so I need the elastic
> material to be workable down to -40 degrees.
>
> Anyone have some leads for these types of pads?. I have found
> several manufacturers for the typical machinery pads, but they are
> loaded in compression not shear.
Christopher Wright P.E. |"They couldn't hit an elephant at
chrisw@skypoint.com | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania
1864)
http://www.skypoint.com/members/chrisw/
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