Subject: RE: Simpson Table
Date: Mon, 21 May 2001 21:21:17 -0500
From: "Rood, Omar" <Omar.Rood@mts.com>
To: "Lundbeck, Jeff" <Jeff.Lundbeck@mts.com>, "Larson, Rod"
     <Rod.Larson@mts.com>, "Sydeski, Ray" <Ray.Sydeski@mts.com>
CC: "Schwartzkopf, Steve" <Steve.Schwartzkopf@mts.com>

Jeff,

Do not fill the table with sand or rock, same will uncouple during
vibration and the mass will be effective only at low frequency
operation, even with baffles.  We would end up making powder of the
rock.

Please continue to try figure out a way to use bolt on weights.  Or
perhaps lead fillers that are wedged in to the pockets you are
suggesting filling with rock?

Omar

>  -----Original Message-----
> From:         Lundbeck, Jeff
> Sent: Monday, May 21, 2001 11:11 AM
> To:   Rood, Omar; Larson, Rod; Sydeski, Ray
> Cc:   Schwartzkopf, Steve
> Subject:      Simpson Table
>
> For initial contract we want table mass to be about 40,000 lbs. for
> control smoothness.  My understanding is that they want option to add
> another 25 ft table and drive both with same actuator, meaning initial
> table mass would have to change to 20,000 lbs. so actuator is driving
> same mass.  What do you think about filling table cavities with sand
> or rock so it can "easily" removed later (concrete may be difficult)?
> Baffles could be used for lateral stiffeners and also prevent fill
> from shifting too much.  If cavities are essentially full, then there
> shouldn't be much/any shifting during test which might create a
> control disturbance.  Cavities could have access ports through beam
> web and would have to be sealed to prevent contaminating table
> bearings.
>
> Ref:  three I-beams, W36 x 194, 26 ft long would weigh 15,130 lbs.  A
> top plate and internal stiffeners would bring it close to 20,000 lb.
> phase 2 goal.  20,000 lbs. of additional mass for 40,000 LB phase 1
> goal is a lot of volume to add/remove and essentially makes table a
> solid structure (of some composite density).  Bolt on weights is
> probably impractical.
>
> What do you think?
>
> Jeff L
