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LHC IRQ Tie Bar Redesign Using Sleeves – Preliminary. T. Nicol May 25, 2007. Current tie bar installation. Preliminary analysis. Assumed vacuum load: 20,000 lb total or 5,000 lb per rod (89,000 N) Maximum distance between vacuum vessel ears: 81” (2050 mm) Assume pinned ends
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LHC IRQ Tie Bar Redesign Using Sleeves – Preliminary T. Nicol May 25, 2007
Preliminary analysis Assumed vacuum load: 20,000 lb total or 5,000 lb per rod (89,000 N) Maximum distance between vacuum vessel ears: 81” (2050 mm) Assume pinned ends Assume S.F. of 4 Pcr = p2EI/l2 = 20,000 lb For stainless steel the minimum value for I = 0.475 in4 Need ID = 1.25” to be compatible with current geometry Solving for OD yields OD = 1.86” so use 2” Actual I = 0.66 in4 so S.F. ~ 5.6
Attachment to existing ear At the magnet ears, the tie bar attaches with a 30 mm bolt. The bronze to stainless interface slides during pressure loading.
Attachment to sliding sleeve Each tie bar joins at the sliding sleeve ear. This is where each is adjusted for length, preloaded slightly, then locked in position.
Typical tie rod assembly Tie rod sleeve – 2” OD, 1.25” ID Threaded insert – 30 mm thread ID, 42 mm thread OD Insert – 30 mm thread ID, 42 mm smooth OD Jam nut
Typical assembly – v2 Outer nut omitted to prevent excessive load in the event of a cryogen spill inside the vacuum vessel
Typical assembly – v2 Nut to tighten sleeve against intermediate ear Nut to tighten assembly against vacuum vessel ear 2” OD, 1.25” ID sleeve Tie rod, nuts, and spherical washers are the same as those in the current system Spherical washers Tie rod
Q1 to Q2 tie rod assembly MB-390923(420 mm sleeve) MB-390925(1162 mm sleeve) 30 mm tie rod Typical end detail 30 mm hex nuts (2) Spherical washers (2 pairs) 30 mm jam nut (1)
Q2 to Q3 tie rod assembly MB-390924(620 mm sleeve) MB-390925(1162 mm sleeve) 30 mm tie rod Typical end detail 30 mm hex nuts (2) Spherical washers (2 pairs) 30 mm jam nut (1)
Q3 to DFBX tie rod assembly MB-390926(682 mm sleeve) 30 mm tie rod Stiffener plates (2) Typical end detail 30 mm hex nuts (2) Spherical washers (2 pairs) 30 mm jam nut (1)