Minutes of the Tracker-Grid
Interface Design Meeting, 6 Jan 2004.
Reference documents: See the 5 Jan and 6 Jan links on
http://www-glast.slac.stanford.edu/Tracker-Hardware/ART/vibe/vibe.html.
Attendees: Bhatnagar, Black, Bloom, Borden, Campell,
Foss, Fransen, Gawehn, Grist, Johnson, Ku, Martin, Nordby, O'Heron, Seipel,
Swensen, Tahmasebi
The primary objective of the
meeting was to review a proposed change in this Interface from the baseline design
adopted in December. The baseline
required epoxy shims to take up slack (tolerance accumulation) in 9 of the 12
boltholes; the new design utilizes nested dual off-center cones for this
purpose.
The primary outcome of the
meeting was strong consensus to change to the new Interface design, although
there are some questions about tolerancing, bearing surfaces, and stresses that
need to be worked through. Martin
Nordby, Tom Borden, Mike Foss, BJ, and others will work together to produce a
full set of drawings with tolerances by COB next Tuesday (13 Jan). John Ku, Erik Swensen, and others will work
together to produce a final set of stress and safety margin analysis values by
the same time. The same group will meet
again next Wednesday (14 Jan) at 8 am PST to review drawings, analysis, and the
initial development plan (test objects and test plan).
In addition, there was a
strong consensus that the baseline Interface design for the mid-span flexures
be changed: the baseline called for a
bolthole pattern offset somewhat from the Tracker tower centerline to avoid
interference of bolts between adjacent towers.
The new drawings will show "nested" bolt patterns designed to
keep the load path through the center of the flexure.
Finally, an alternative to the
3 primary locating points was considered:
that these points be fastened with pins instead of single cones shown in
the December baseline design. Here, the
consensus was to stay with cones.
-- Jim Martin
650 926 4895