Support for the spherical detector tank

From: Hans Jostlein <>
Date: Thu Sep 02 2004 - 15:34:49 CDT

Encouraged by Vic Guarino's detector structural report (on the web page), we
have looked at a slightly different support design.
Ang Lee has done an FEA analysis of stresses and deflections for a support
similar to the one used on MiniBooNE, but with an added frame near the floor
and some diagonal members, to make it possible to support it on 4 Hillman
rollers instead of anchoring it to the floor.
The four support columns provide also natural places to attach lifting

The results are quite encouraging.
Case 1 analyzes the detector while at rest, on a perfectly balanced support
(e.g. a hydrauklic force-equalizing system of jacks)
Case 2 assumes one support point is deliberately moved 1/16 inch from the
balance conditions.
            Still no probems.
Case 3 looks at what happens when the equalizing system fails and only two
diagonally opposed legs hold all the weight.
            Stresses and deflection are still acceptable.
To understand what happens when the detector is accelerated upward by 1 g
during a move, one simply doubles all stresses and deflections of case 1.
            Things are still acceptable.
However, one cannot combine case 3 with the 1 g acceleration case.
That means, in practical terms, that the column loads should be nearly
equalized while moving the detector.
This means that we may want to add passive cushioning or other means (such
as sufficiently elastic Nylon slings) when moving the detector,
or monitor the performance of the load balancing system while moving.

Comments, ideas, and suggestions are welcome.



Received on Thu Sep 2 15:40:34 2004

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