Joseph Rasson, LBL
Tom Peterson, Fermilab
CERN
24 April 2007

• Introduction
• Documentation
• Flow schematic
• Line pressures
• Mechanical Test Protocol
• Piping and Interface Layouts
• Mechanical Loads
• Free body and force diagrams
• Peak stresses
• Transport
• Conclusion
• Future Activities
24 April 2007 DFBX 2

• DFBX designed at LBNL and fabricated at Meyer
Tool near Chicago Illinois
• Fabrication oversight performed by Fermilab
• Present team consists of
– Joseph Rasson (LBL), project manager
– Steve Virostek (LBL), engineer
– Frederic Gicquel (LBL @ CERN), engineer
– Tom Peterson (Fermilab), engineer
– Phil Pfund (Fermilab), engineer
24 April 2007 DFBX 3

24 April 2007 DFBX 4

24 April 2007 DFBX 5

24 April 2007 DFBX 6

• http://www-td.fnal.gov/LHC/Uslhc_accel_docs/Documents.html
–
Fabrication documentations for DFBX and LQX.
• http://sc-gs.web.cern.ch/sc-gs/gs_ms/TISUS/
– Safety related documentation submitted to CERN.
• http://tomato.fnal.gov/lhcirq/DFBXimages/IndexDFBX.html
–
Pictures of DFBX during fabrication at the vendor.
• http://www-eng.lbl.gov/~rasson/DFBX%20DWGS_APRIL_07/
– Drawings of the DFBX.
24 April 2007 DFBX 7

• The inner triplet cryogenic flow schematic was developed in close collaboration between
– Rob Van Weelderen (CERN)
– Jon Zbasnik (LBL)
– Tom Peterson (Fermilab).
• The following are excerpts from the DFBX G/C and DFBX E flow schemes.
24 April 2007 DFBX 8

• 8 DFBX’s, 6 different types
– QRL on wall side, so left and right at each location differ in being “left handed” and “right handed”
– Points 2 and 8 have the same configuration with cold
D1, so DFBX C is identical to G and DFBX D is identical to H.
– Points 1 and 5 differ from 2 and 8 in having warm D1 and differ from each other in having opposite slopes.
24 April 2007 DFBX 9

Flow schematic for IP8 left
Following slide shows the
DFBXG detail
24 April 2007 DFBX 10

DFBX-G lines with 20 bar design
(the largest high-pressure lines)
Helium vessel
24 April 2007 DFBX 11

Flow schematic for IP5 left
Following slide shows the
DFBXE detail
24 April 2007 DFBX 12

DFBX-E lines with 20 bar design
(the largest high-pressure lines)
Helium vessel
24 April 2007 DFBX 13

Reference: LHC Project Note 135
24 April 2007
Approx. operating pressure (bar absolute)
MAWP
(design pressure, surrounded by vacuum)
(bar abs)
4.0
Test pressure in vacuum
(MAWP x
1.25)
(bar abs)
Relief valve set pressure
(bar abs)
5.0 4.0 Subatmospheric helium lines (XB,
CY1, CY2)
Lines connecting to the helium vessel and current leads
(CC’1, DH)
Pressurized superfluid lines
(LD1, LD2, LD3,
MQX1, MQX2,
MBX1, MBX2)
Beam screen tubes
(CC’2, CC’3)
Thermal shield lines
(E!, E2, EX)
Vacuum vessel
0.016
1.3
1.3
3.6
19
0
3.5
20.0
20.0
22.0
4.4
25.0
25.0
27.5
1.4
3.0
20.0
20.0
22.0
1.05 1.2 bar abs surrounded by air
DFBX 14

Tests at the manufacturer (Doc. M989A):
• Cold shock all welds at least one cycle
• Cold shock chimney bellows 25 cycles
• Pressure test all components at set test pressure
• Vacuum leak check all components
• Final system pressure test and vacuum leak check
• Measurements of all critical dimensions
Vacuum leak checks and measurement of critical dimensions were repeated at CERN after shipping:
See Doc LHC-DFBX-001-10-00
24 April 2007 DFBX 15

DFBX Piping Layout
D1 End
Q3 End
24 April 2007 DFBX 16

24 April 2007 DFBX 17

24 April 2007 DFBX 18

24 April 2007 DFBX 19

• Mechanical loads on the DFBX are Generated from:
– Thermal contraction of spool pieces and magnets
– Thrust load from bellows (positive and vacuum pressures)
– Internal pressure (positive and vacuum pressures)
– Gravitational loads (weight)
24 April 2007 DFBX 20

Forces from Thermal Contractions
• Dominated by contraction of magnet ends away from DFBX
– Q3 lines pull back 16.3 mm
– D1 lines pull back ~20mm D1 fixed support at Center
• Internal DFBX components: Max thermal contractions is ~ 6 mm
• Design Approach:
Neutralize mechanical forces generated from thermal contraction with the use of flex hoses
24 April 2007 DFBX 21

Design Approach for Thermal Contraction
Welded ring to carry weight of pipe on G10 Spider Assy
Flex hoses to take up thermal contraction and pipe misalignment
Pipes are installed such as flex hoses are preflexed half way when warm.
Flexhose moves
+/- thermal contraction length
24 April 2007 DFBX 22

Welded ring to carry weight of pipe on G10 Spider Assy
Large diameter flex hose: 50.8 mm Dia
24 April 2007 DFBX 23

• Weight of most spool pieces is supported on
G10 spiders in jumpers
• Spiders also provide mean to keep the pipes aligned during and after interconnection
• Weight of LHe vessel and bus ducts is transferred to vacuum vessel via 4- 19 mm invar rods (to be discussed later)
24 April 2007 DFBX 24

Double spiders in jumpers carry the weights of small pipes and guide/align pipes
12.7 mm thick G10 plates
6.4 mm mm thick G10 split Pipes
24 April 2007 DFBX 25

D1 End
Non Load Bearing G10 Support Spiders
22.2 mm thick G10 plate
12.7 mm thick G10 plates
Bus duct SS support clamps and split rings
24 April 2007 DFBX
Q3 End
Beam pipe
Center support
Attached to
LHe vessel
26

• Limited to components with bellows at the ends for ease of interconnect and to allow for thermal contraction:
• XB: Q3-DFBX pumping line
• MQX1: Q3-DFBX bus duct
• MBX1: D1-DFBX bus duct
• LD cross-over line inside the box whenever we have cold D1 (4 boxes)
24 April 2007 DFBX 27

English Units
DFBX Thrust Loads
Si Units
Line
XB
MQX1
MBX1
LD
D mean
(in)
Pres
Design
(bar)
4.45
4.45
3.16
2.54
4
20
20
20
F (lb)
902
4510
2274
1469
Line
XB
MQX1
MBX1
LD
D mean
(mm)
Pre
Design
(bar)
113.0
113.0
80.4
64.5
4
20
20
20
F (N)
4012
20062
10116
6536
24 April 2007 DFBX 28

XB Line with Flow Separator
D1 20 mm Thermal contraction
Q3-XB Thrust: 4 KN
24 April 2007
Flex hose for alignment
Flex hose for thermal contraction
DFBX 29

3 Gravity Vertical Supports
2 Thrust Supports to vacuum vessel
Supports
24 April 2007 DFBX 30

XB without Flow Separator
One gravitational support
2 Horizontal Thrust Supports
24 April 2007 DFBX 31

Bus Duct Assembly: Thrust Load
Q3: 20 KN
24 April 2007
LD: 6.5 KN
Thrust Support Brackets
DFBX
D1: 10.1 KN
32

LHe Vessel Support
24 April 2007 DFBX 33

End view showing helium vessel axial supports and beam tube support
24 April 2007 DFBX 34

LHe Vessel Bottom Support to Vacuum Plate
24 April 2007 DFBX 35

DFBX-E
17 Feb 05
24 April 2007 DFBX 36

• General diagrams showing approximate magnitude of force
• More detailed analysis will be presented at the component level
24 April 2007 DFBX 37

Forces on DFBX-E due to pressure of 3.5 bar in the helium vessel plus gravity
66.8 kN (15000 lbf)
635 mm
(25.0 in)
16.7 kN (3750 lbf) x 2
(rods in tension)
24 April 2007
767 mm
(30.2 in)
DFBX
16.7 kN (3750 lbf) x 2
(rods in tension)
38

Forces on DFBX-E due to M1 line pressure of 20 bar plus gravity (no helium vessel pressure)
4.4 kN (1000 lbf)
3.0 kN (680 lbf) x 2
(rods in compression)
20.0 kN
635 mm
(4500 lbf)
(25.0 in)
10.0 kN (2250 lbf) x 2
24 April 2007
767 mm
(30.2 in)
5.4 kN (1180 lbf) x 2
(rods in tension)
DFBX 39

Forces on DFBX-E due to 20 bar M1 line pressure plus 3.5 bar in the helium vessel
66.8 kN (15000 lbf)
(Combined pressure and gravity)
20.0 kN
635 mm
(4500 lbf)
(25.0 in)
10.0 kN (2250 lbf) x 2
20.8 kN (4680 lbf) x 2
(rods in tension)
24 April 2007
767 mm
(30.2 in)
DFBX
12.5 kN (2820 lbf) x 2
(rods in tension)
40

Forces on DFBX-C due to
20 bar M1 line pressure plus 3.5 bar in the helium vessel
82.3 kN (18500 lbf)
(Combined pressure and gravity)
10.1 kN
( 2280 lbf)
5.0 kN (1110 lbf) x 2
22.6 kN (5090 lbf) x 2
(rods in tension)
24 April 2007
767 mm
(30.2 in)
DFBX
635 mm
(25.0 in)
20.0 kN
(4500 lbf)
18.5 kN (4170 lbf) x 2
(rods in tension)
41

Forces on DFBX-C due to
3.5 bar in the helium vessel
82.3 kN (18500 lbf)
635 mm
(25.0 in)
767 mm
(30.2 in)
24 April 2007
20.6 kN (4630 lbf) x 2
(rods in tension)
DFBX
20.6 kN (4630 lbf) x 2
(rods in tension)
42

•Analysis assumptions and methodology
•He vessel supports - stress analysis
•Upper, vertical support rods and attachments
•Lower, axial supports and attachments
• He vessel cover plate weld – stress analysis
•Bus duct
•XB line – load and stress analysis
•Vacuum Vessel Bumpers

•Analyses assume worst case operating loads
•3.5 bar absolute in helium vessel
•20.1 kN (4510 lb) bus duct thrust load (20 bar)
•XB line thrust
•4.0 kN (902 lb) thrust load (4 bar)
•Possible added load from D1 line
•All components are assessed based on the
•Code limits are for guidance and not a hard requirement

• Reaction loads are based on the results of the helium vessel FEA model runs
• A portion of the bus duct thrust load is reacted at the stack bellows due to their high lateral stiffness
• Vertical strut loads are affected by the moment from bus duct thrust load
• The worst case vertical support rod and axial support loads are used for all analyses
•Peak axial support load: 8.7 kN (1962 lb)
•Peak strut tensile load (Q3 side): 15.9 kN (3570 lb)
•Peak strut tensile load (D1 side): 19.6 kN (4414 lb)
•Peak strut compressive load: 3.03 kN (682 lb)

•Material stress allowable limits from code
•SS 304L: 115 MPa (16.7 ksi) tensile stress
•SS 18-8: 130 MPa (18.8 ksi) tensile stress
•Invar: 276 MPa (40 ksi) yield stress (not from code)
•PV code limits have built-in safety factors
•S.F. ~2 on yield and >4 on ultimate stress
•For welds, efficiency factors are applied
•Tensile and shear stresses are combined

Calculation Details
Material: 304L stainless steel
Net axial load: 8.7 kN (1962 lb)
Weld size: 9.65 mm (0.38”)
Moment arm: 36 mm (1.4”)
Weld A: 1560 mm 2 (2.42 in 2 )
Weld I: 4.40x10
5 mm 4 (1.06 in 4 )
Tensile stress: 13.4 MPa (1.95 ksi)
Shear stress: 5.6 MPa (0.81 ksi)
Equivalent stress: 16.6 MPa (2.40 ksi)
Allowable stress: 115 MPa (16.7 ksi)
Weld efficiency factor: 0.55
Net allowable stress: 63.3 MPa (9.19 ksi)
Weld

Calculation Details
Material: 304L stainless steel
Net axial load: 8.7 kN (1962 lb)
Moment arm: 36 mm (1.4”)
Block A: 2903 mm 2 (4.50 in 2 )
Block I: 3.51x10
5 mm 4 (0.84 in 4 )
Tensile stress: 16.8 MPa (2.44 ksi)
Shear stress: 3.0 MPa (0.44 ksi)
Equivalent stress: 17.6 MPa (2.56 ksi)
Allowable stress: 115 MPa (16.7 ksi)

Rod Calculation Details
Material: Invar ½” all thread
Net axial load: 4.4 kN (981 lb)
Rod stress area: 91.5 mm 2 (0.142 in 2 )
Tensile stress: 47.7 MPa (6.91 ksi)
Yield stress: 276 MPa (40 ksi)
Assume load is shared equally on both sides of 2-sided rod
Nut Calculation Details
Material: 18-8 stainless steel
Net axial load: 4.4 kN (981 lb)
Nut shear stress area: 211 mm 2 (0.33 in 2 )
(based on load carried by 3 threads)
Equivalent stress: 35.9 MPa (5.21 ksi)
Allowable stress: 130 MPa (18.8 ksi)
Both rods and nuts can carry the full load at one end of the rod if machining and assembly tolerances lead to unequal loading

Calculation Details
Material: 304L stainless steel
Net axial load: 4.4 kN (981 lb)
Moment arm: 95 mm (3.8”)
Area: 1976 mm 2 (3.06 in 2 )
Mom. area I: 3.25x10
5 mm 4 (0.78 in 4 )
Bending stress: 28.4 MPa (4.12 ksi)
Shear stress: 2.2 MPa (320 psi)
Equivalent stress: 28.7 MPa (4.16 ksi)
Allowable stress: 115 MPa (16.7 ksi)
One stanchion can carry the full load if machining and assembly tolerances lead to unequal loading
Peak Stress

Bolt Stress Calculation Details
Material: 18-8 stainless steel
Bolt size: M16-1
Assume tensile and shear carried by 1 bolt
Axial force due to moment: 4.7 kN (1065 lb)
Stress area: 175 mm 2 (0.27 in 2 )
Tensile stress: 27.1 MPa (3.93 ksi)
Shear stress: 25.0 MPa (3.62 ksi)
Equivalent stress: 51.0 MPa (7.40 ksi)
Allowable stress: 130 MPa (18.8 ksi)
One bolt in one stanchion can carry the full load if machining and assembly tolerances lead to unequal loading
Thread Engagement Details
Bolt length: 45 mm
Stanchion thickness: 25.4 mm
G-10 shim thickness: 3.3 mm
Washer thickness: 3.0 mm
Net thread engagement: 13.3 mm
No. engaged threads: 13
Minimum threads required: 3 to 5

Calculation Details
Material: 18-8 stainless steel
Bolt size: M16-1
Stress area: 175 mm 2 (0.27 in 2 )
Yield stress: 276 MPa (40 ksi)
Bolt load: 24.1 kN (5420 lb) @ 50% yield
Force per stanchion: 48.2 kN (10.8 k-lb)
Coefficient of friction: 0.4 (G-10/SS)
Static friction force: 19.3 kN (4336 lb)
Axial stanchion force: 4.4 kN (981 lb)
•Friction force is sufficient to prevent slipping, even if the full force on one side acts on a single stanchion
•If slipping occurs due to low bolt torque, motion is limited to 0.75 mm radial clearance on bolt holes
•Stanchions, bolts and rods can handle full force on one side

Calculation Details
Material: 304L stainless steel
Maximum strut load: 19.6 kN (4414 lb)
Weld size: 12.7 mm (0.50”)
Moment arm: 59 mm (2.31”) (longer clevis)
Weld A: 1866 mm 2 (2.89 in 2 )
Weld I: 10.4x10
5 mm 4 (2.50 in 4 )
Tensile stress: 31.7 MPa (4.60 ksi)
Shear stress: 10.5 MPa (1.53 ksi)
Equivalent stress: 36.6 MPa (5.31 ksi)
Allowable stress: 115 MPa (16.7 ksi)
Weld efficiency factor: 0.55
Net allowable stress: 63.3 MPa (9.19 ksi)
Weld

Analysis Parameters
Material: 304L stainless steel
Maximum strut load: 26.7 kN (6005 lb)
Allowable stress: 115 MPa (16.7 ksi)
Shear Pullout Calculation Details
Shear pullout area: 317 mm 2 (0.49 in 2 )
(load spread over 4 areas at each clevis)
Shear stress: 15.5 MPa (2.25 ksi)
Equivalent stress: 26.8 MPa (3.89 ksi)
Clevis Pin Calculation Details
Pin diameter: 19.1 mm (0.75 in)
Pin area: 285 mm 2 (0.442 in 2 )
Shear stress: 34.4 MPa (5.00 ksi)
Equivalent stress: 59.7 MPa (8.65 ksi)
Clevis Bending Stress Calculation
Moment arm: 24 mm (0.94”)
(at base of rod end cut-out)
Area: 1288 mm 2 (2.00 in 2 )
Mom area I: 1.76x10
5 mm 4 (0.43 in 4 )
Bending stress: 76.1 MPa (11.0 ksi)
Shear stress: 15.2 MPa (2.21 ksi)
Equivalent stress: 80.6 MPa (11.7 ksi)
(load shared over 2 clevis sides)

Strut Body Stress Calculation Details
Material: Invar
End thread size: ¾”-16 UNF
Peak axial force: 26.7 kN (6005 lb)
Thread stress area: 241 mm 2 (0.373 in 2 )
Tensile stress: 81.6 MPa (11.8 ksi)
Yield stress: 276 MPa (40 ksi)
Tension
In Strut
Strut Buckling Analysis
Material: Invar
Modulus: 141 GPa (20.5 Mpsi)
Rod diameter: 19.1 mm (0.75”)
Mom. area I: 0.647x10
5 mm 4 (0.016 in 4 )
Rod length: 760 mm (29.1”) (pinned ends)
Peak compressive force: 3.03 kN (682 lb)
Critical load: 15.6 kN (3513 lb)
Strut Rod Ends
Rod end: Aurora ¾” S-12
Peak load: 19.6 kN (4414 lb)
Allowable load: 32.7 kN (7364 lb)

L-bracket Weld Calculation Details
Material: 304L stainless steel
Maximum strut load: 19.6 kN (4414 lb)
Weld size: 6.35 mm (0.25”)
Block depth: 64 mm (2.5”)
Block width: 38 mm (1.5”)
Moment arm: 19.1 mm (0.75”)
Weld A: 912 mm 2 (1.41 in 2 )
Weld I: 5.36x10
5 mm 4 (1.29 in 4 )
Tensile stress: 21.5 MPa (3.12 ksi)
Bending stress: 22.1 MPa (3.21 ksi)
Equivalent stress: 43.7 MPa (6.33 ksi)
Allowable stress: 115 MPa (16.7 ksi)
Weld efficiency factor: 0.55
Net allowable stress: 63.3 MPa (9.19 ksi)

Added Clevis Weld Calculation Details
Material: 304L stainless steel
Maximum strut load: 19.6 kN (4414 lb)
Weld size: 6.35 mm (0.25”)
Weld length: 38 mm (1.5”)
# of welds per support: 4
Weld area: 684 mm 2 (1.06 in 2 ) total
Shear stress: 28.7 MPa (4.16 ksi)
Equivalent stress: 49.7 MPa (7.21 ksi)
Allowable stress: 115 MPa (16.7 ksi)
Weld efficiency factor: 0.55
Net allowable stress: 63.3 MPa (9.19 ksi)
Clevis Shear Pullout Calculation Details
Shear pullout area: 242 mm 2 (0.375 in 2 )
Shear stress: 27.6 MPa (4.00 ksi)
(load spread over 4 areas at each clevis)
Equivalent stress: 35.1MPa (5.10 ksi)
Welds
Added clevis
Bolt

Boss Weld Stress Calculation Details
Material: 304L stainless steel
Maximum strut load: 15.9 kN (3570 lb)
Weld size: 12.7 mm (0.50”)
Moment arm: 64 mm (2.50”) w/adapter
Weld A: 1328 mm 2 (2.06 in 2 )
Weld I: 3.81x10
5 mm 4 (0.916 in 4 )
Tensile stress: 50.4 MPa (7.31 ksi)
Shear stress: 12.0 MPa (1.73 ksi)
Equivalent stress: 54.5 MPa (7.90 ksi)
Allowable stress: 115 MPa (16.7 ksi)
Weld efficiency factor: 0.55
Net allowable stress: 63.3 MPa (9.19 ksi)
Clevis Shear Pullout
Same shear area as horizontal wall support with a lower load

• Vessel cover plate is welded to frame using a single, continuous external fillet weld
• Allows for cover removal by grinding if access is needed
• This weld type is an exception to
ASME pressure vessel code
• A 2D finite element model predicts the actual weld stresses to allow exception to code
• Allowable stress is exceeded only in very small zone at the root of the weld (root stress < yield stress)
Vessel frame
Cover
Weld

Thrust Load
24 April 2007 DFBX
Weld Clamp
Thrust Support
Plate Welded to
LHe Vessel
60

“Weld Clamp”
Bus duct thrust support
24 April 2007
Support Bracket
DFBX 61

Weld Clamp Stress Calculation Details
Material: 304L stainless steel
Peak thrust load: 20.1 kN (4510 lb)
Weld size: 1.59 mm (1/16”) 2 sides of clamp
Weld diameter: 48.3 mm (1.90”)
Shear stress: 61.5 MPa (8.92 ksi)
Equivalent stress: 107 MPa (15.4 ksi)
Allowable stress: 115 MPa (16.7 ksi)
Weld efficiency factor: 0.55
Net allowable stress: 63.3 MPa (9.19 ksi)
Weld clamp
Weld stress exceeds allowable stress dictated by PV code but is still within material strength limits
Thrust support

Thrust Plate Weld Stress Calculation
Material: 304L stainless steel
Peak thrust load: 20.1 kN (4510 lb)
Weld size: 6.35 mm (1/4”)
Weld area: 940 mm 2 (1.46 in 2 )
Weld mom. Area I: 1.61x10
5 mm 4 (0.388 in 4 )
Equivalent stress: 106 MPa (15.4 ksi)
Allowable stress: 115 MPa (16.7 ksi)
Weld efficiency factor: 0.55
Net allowable stress: 63.3 MPa (9.19 ksi)
Thrust plate
Weld stress exceeds allowable stress dictated by PV code but is still within material strength limits

Q3 Side - Bus Duct Thrust Support (thrust plate bending)
Thrust Plate Bending Stress Calculation
Material: 304L stainless steel
Peak axial load: 20.1 kN (4510 lb)
Plate thickness: 12.7 mm (0.5”)
Moment arm: 57.2 mm (2.25”)
Area: 1787 mm 2 (2.77 in 2 )
Mom area I: 2.40x10
4 mm 4 (0.058 in 4 )
Bending stress: 304 MPa (44.0 ksi)
Shear stress: 11.2 MPa (1.63 ksi)
Equivalent stress: 304 MPa (44.1 ksi)
Allowable stress: 115 MPa (16.7 ksi)
Ears
Thrust plate
Weld Clamp Ear Stress Results
Equivalent stress: 127 MPa (18.4 ksi)*
Plate stress exceeds material strength limits – thrust support plate needs reinforcement
Thrust Plate Ear Stress Results
Equivalent stress: 146 MPa (21.2 ksi)*
* Both exceed PV code but are < yield

Thrust Plate Bending Stress Calculation
Material: 304L stainless steel
Peak axial load: 10.1 kN (2274 lb)
Plate thickness: 12.7 mm (0.5”)
Moment arm: 46.0 mm (2.25”)
Area: 1787 mm 2 (2.77 in 2 )
Mom area I: 2.40x10
4 mm 4 (0.058 in 4 )
Bending stress: 123 MPa (17.9 ksi)
Shear stress: 11.2 MPa (1.63 ksi)
Equivalent stress: 125 MPa (18.1 ksi)
Allowable stress: 115 MPa (16.7 ksi)
Material stress exceeds allowable stress dictated by PV code but is well within material strength limits
Thrust plate
Short, double
Plate design

• XB pipe and surge tank uses 3 vertical and 2 horizontal stainless rods to resist thrust loading
• A simple FEA model using beam elements was used to determine the support reaction forces
• Loads: XB bellows thrust (4.0 kN),
D1 line force (0.44 kN), gravity and thermal contraction
• Assume that rods do not support large moments due to pivoting at ends and localized yielding (i.e. forces in rods are essentially axial)
4.0 kN
3.4 kN
1.0 kN
.65 kN
.80 kN
1.0 kN
4.0 kN
.65 kN
3.4 kN
.44 kN

Axial Support Rods
Material: 18-8 stainless steel
Peak axial load: 3.4 kN (770 lb)
Equivalent stress: 68.5 MPa (9.9 ksi )
Allowable stress: 130 MPa (18.8 ksi)
3.4 kN (worst case axial rod load)
Surge tank brackets
Material: 304L stainless steel
Weld size: 2.8 mm (0.11”)
Peak vertical load: 1.0 kN (233 lb)
Equivalent stress: 25.0 MPa (3.62 ksi)
Peak horizontal load: 0.80 kN (179 lb)
Equivalent stress: 14.9 MPa (2.16 ksi)
1.0 kN
Worst case vertical tab weld load
.80 kN
1.0 kN
Horizontal supp’t weld load
Allowable stress: 115 MPa (16.7 ksi)
Weld efficiency factor: 0.55
Net allowable stress: 63.3 MPa (9.19 ksi)

Forked Bracket Bending Stress Calculation
Material: 304L stainless steel
Peak axial load: 3.4 kN (770 lb)
Plate thickness: 12.7 mm (0.5”)
Moment arm: 31.8 mm (1.25”)
Area: 403 mm 2 (0.625 in 2 )
Mom area I: 5.42x10
3 mm 4 (0.013 in 4 )
3.4 kN (worst case axial rod load)
Bending stress: 127 MPa (18.5 ksi)
Tensile stress: 8.5 MPa (1.23 ksi)
Equivalent stress: 136 MPa (19.7 ksi)
Allowable stress: 115 MPa (16.7 ksi)
Material stress exceeds allowable stress dictated by PV code but is well within material strength limits
Bending stress on forked bracket
3.4 kN

• XB pipe (w/o tank) uses 1 vertical and 2 horizontal rods to resist thrust loading
• Load centered on the 2 horizontal supp’ts
• Rod loading less than case with surge tank
0.2 kN
2.0 kN
Circular Plate Bending Stress Calculation
Material: 304L stainless steel
Support load: 2.2 kN (501 lb)
Plate thickness: 9.5 mm (0.375”)
Moment arm: 114 mm (4.5”)
Area: 1089 mm 2 (1.69 in 2 )
Mom area I: 8.23x10
3 mm 4 (0.020 in 4 )
Bending stress: 147 MPa (21.4 ksi)
Shear stress: 2.0 MPa (0.30 ksi)
Equivalent stress: 147 MPa (21.4 ksi)
Allowable stress: 115 MPa (16.7 ksi)
4.0 kN
Material stress exceeds allowable stress dictated by PV code but is within material strength limits
2.0 kN
Circular thrust plate

9770lb
(43.5kN)
13”
Worst case scenario:
-Warm D1
-jacks on IT fully react load
-jacks on DFBX do not react load
=> full vacuum load 19540lb (87kN) on 2 bumpers
Prying force (spread on 2 anchors):
F=13/10*9770=12701lb (56.5kN)
=> 6350lb per anchor
Shear force (spread on 4 anchors):
F=9770lb (43.5kN)
=> 2442.5lb per anchor
24 April 2007
Prying force
10”
Hilti anchors HSL M24/60
Allowable working load in Tension 9860lb (43.8kN)
Allowable working load in shear 17950lb (79.8kN)
Stand offs rated at 20000lb each
Pivot point
DFBX 70

Local Max stresses at 136 MPa
Yield at 190Mpa
24 April 2007 DFBX 71

The DFBX were shipped in pairs, each in its own three-piece shipping frame
Boxes C being placed in base of shipping frame. Shock recorders have been mounted on each side of frame (one visible on this side). Two more are mounted on the top plate of DFBX.
24 April 2007 DFBX
Boxes C & G at CERN.
One of two shock recorder mounted on frame is shown in insert. Another is mounted on the other side and two are mounted on the top plate of each DFBX.
72

• Detailed analyses were performed during design phase based CERN requirements
• Continued oversight during the fabrication phase to insure that specifications were met
• Cold shocks, pressure tests and vacuum leak checks were performed at the component level at the manufacturer and
CERN
• Analysis confirmed that the LHe vessel structure is robust
• During the last month the DFBX mechanical structure was reviewed and much of it was analyzed
– FNAL organized two peer reviews
24 April 2007 DFBX 73

• The analysis confirmed that the bus duct thrust support is marginal
– “Weld Clamp” was not welded
– Support bracket is too thin
• Review and analysis of other components of the box revealed additional that should be upgraded
– Eliminate LHe vessel vertical rods linkage dependence on friction generated by bolt tightness
24 April 2007 DFBX 74

• Continue reviewing and analyzing key aspect of
DFBX as built
• Design and implement improved bust duct support
• Perform simulated thrust load tests
• Review of all cooldown and warmup conditions to look for potential interferences
24 April 2007 DFBX 75