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