Shear Problem Defined• There are no bolts on the inboard side of the coil

structure to account for shear forces.

Coefficent of Friction Needed to Prevent SlipNonLinear, Baseline w/Gaps at Wings - No Slip Inner Leg (hm10)

No Bolts in Inner Leg

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cc2

b

cc2

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brl

bc2

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Joint-Location

mu

Bottom Line: friction alone will not prevent sliding. (how much sliding that would ultimately result is unanswered)

What an individual shim would look like with shear pins

53 pins on approx 2.5” centers 70 pins on approx 2” centers

Design will be similar to the left figure (with 50 pins per section)

Assembly Steps

1. Drill holes in shims, note which holes goes with each stud on either a or b modular coil face.

2. Line up shim with each MC Face and mark the appropriate stud locations

3. Shoot studs and grind off filets4. Install g-10 bushings onto studs 5. Place Shim over horizontal coil then move the

upper modular coil down onto the shim.6. Insert Stycast, clean excess, wait 24 hrs for

cure.

SST Shims, G-10 Shims, bushings and pins

Test Fixture

Welded stud

bushing

epoxy

G-10 shim

Steel shim

Outer pull plate is Outer pull plate is invisibleinvisible

Test Fixture Assembly

• The four half inch studs were welded on at the MDL laboratory onto the two pull plates. The pins had very little tilt to them and were fairly normal to the plates.

• The weld bead was then ground off and the studs were cut back to 3/8” long.

• This procedure can be performed at PPPL in the same manner as was done at MDL.

• All other parts of the fixture (excluding the studs), were machined at a local machine shop.

• Stycast delivery system for both horizontal and vertical positions is under trial at MDL.

Testing Summary

Results • Fixture was pulled at 15,000 lbs, (3,750 lbs/pin), Deflection measured was

7 mils. This was more than three times the amount predicted by the FEA program using material properties supplied by the manufacturer.

• Large gaps 1/8” are seen in the level of the stycast compared to the sst shim on the upper sst plate.

• After removing bottom pull plate and breaking the stycast, Multiple air bubbles were observed throughout the material (largest bubble approx dia = 3/16”)

Path Forward• Inject Stycast from the side of each hole (instead of top) using Zerc fittings

and hypodermic needle or alternate. Status: Under investigation• Two holes will be drilled to allow for insertion and vacuum pulling of stycast

around each bushing. Status: complete • Deair stycast until bubbling has ceased using vacuum (Use prototype to

test Stycast mixture for presence of bubbles) Status: complete (excellent results)

• Limit stirring of Stycast. Status: complete • Test Stycast samples in LN2 environment to test compressive strength.

Status: complete…results pending