Subject: RE: Simpson Table
Date: Tue, 22 May 2001 17:57:29 -0500
From: "Lundbeck, Jeff" <Jeff.Lundbeck@mts.com>
To: "Rood, Omar" <Omar.Rood@mts.com>
CC: "Larson, Rod" <Rod.Larson@mts.com>, "Sydeski, Ray"
     <Ray.Sydeski@mts.com>, "Schwartzkopf, Steve"
     <Steve.Schwartzkopf@mts.com>

I looked again at bolting steel plates on to reach 40,000 goal.  We
would need two steel plates 4" thick x 29" wide, 25 ft long to give us
about 20,000 LB additional weight.  These plates would bolt onto outside
surface of I-beam webs.  Plates are probably multi piece for handling
and to fit around table lateral stiffeners and bearing access holes.
Bolting on weights requires tapped holes in side of table resulting in
two additional setups and more machining time on large mill (we don't
have any other features requiring mill setup on side of table).  Steel
weights would be flame cut shapes, may be $0.50-.80/lb (or more?) giving
a weight material cost of $10k-16k, plus we need to tap lifting holes.
Seems like a lot of money for something that might get thrown away.  Is
the additional mass that important, or would less additional mass be
acceptable?  I can check with Brian Kirchmann to see if there is cheaper
way to get weights, i.e. iron or lead castings.  Cost is only drawback I
see.
Jeff

> -----Original Message-----
> From: Rood, Omar
> Sent: Monday, May 21, 2001 9:21 PM
> To:   Lundbeck, Jeff; Larson, Rod; Sydeski, Ray
> Cc:   Schwartzkopf, Steve
> Subject:      RE: Simpson Table
>
> 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
