1. DFBX Thermo-Mechanical Review
Joseph Rasson, LBL
Tom Peterson, Fermilab
CERN
24 April 2007

2. DFBX Presentation Outline
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

3. Introduction
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 CERN), engineer
Tom Peterson (Fermilab), engineer
Phil Pfund (Fermilab), engineer
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DFBX

4. 24 April 2007
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5. 24 April 2007
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6. 24 April 2007
DFBX

7. DFBX Documentation
Fabrication documentations for DFBX and LQX.
Safety related documentation submitted to CERN.
Pictures of DFBX during fabrication at the vendor.
Drawings of the DFBX.
24 April 2007
DFBX

8. Flow schematic
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.
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DFBX

9. Overview of DFBX Flow Schemes
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.
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DFBX

10. Flow schematic for IP8 left Following slide shows the DFBXG detail
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DFBX

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

12. Flow schematic for IP5 left Following slide shows the DFBXE detail
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DFBX

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

14. Pressures Reference: LHC Project Note 135
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DFBX

15. Mechanical Test Protocol
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
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DFBX

16. DFBX Piping Layout
D1 End
Q3 End
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17. 24 April 2007
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18. DFBX – Q3 Interface
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19. DFBX – Q3 Interface
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20. Mechanical Loads 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

21. 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

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

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

24. Gravitational Loads
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 mm invar rods (to be discussed later)
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DFBX

25. 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
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DFBX

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

27. Thrust Loads in DFBX
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)
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DFBX

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

29. XB Line with Flow Separator
D1 20 mm Thermal contraction
Flex hose for alignment
Flex hose for thermal contraction
Q3-XB Thrust: 4 KN
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30. XB Supports 3 Gravity Vertical Supports 2 Thrust Supports
to vacuum vessel
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31. XB without Flow Separator
2 Horizontal Thrust Supports
One gravitational support
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DFBX

32. Bus Duct Assembly: Thrust Load
D1: KN
LD: 6.5 KN
Q3: 20 KN
Thrust Support Brackets
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33. LHe Vessel Support
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34. End view showing helium vessel axial supports and beam tube support
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35. LHe Vessel Bottom Support to Vacuum Plate
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36. DFBX-E
17 Feb 05
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37. Free Body Diagrams
General diagrams showing approximate magnitude of force
More detailed analysis will be presented at the component level
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38. Forces on DFBX-E due to pressure of 3
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)
767 mm
(30.2 in)
16.7 kN (3750 lbf) x 2
(rods in tension)
16.7 kN (3750 lbf) x 2
(rods in tension)
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DFBX

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

40. (Combined pressure and gravity)
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
(4500 lbf)
635 mm
(25.0 in)
10.0 kN (2250 lbf) x 2
767 mm
(30.2 in)
20.8 kN (4680 lbf) x 2
(rods in tension)
12.5 kN (2820 lbf) x 2
(rods in tension)
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DFBX

41. (Combined pressure and gravity)
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)
20.0 kN
(4500 lbf)
10.1 kN
( 2280 lbf)
635 mm
(25.0 in)
5.0 kN (1110 lbf) x 2
767 mm
(30.2 in)
22.6 kN (5090 lbf) x 2
(rods in tension)
18.5 kN (4170 lbf) x 2
(rods in tension)
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DFBX

42. 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)
20.6 kN (4630 lbf) x 2
(rods in tension)
20.6 kN (4630 lbf) x 2
(rods in tension)
24 April 2007
DFBX

43. DFBX Detailed Analysis
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 & thrust support – stress analysis
XB line – load and stress analysis
Vacuum Vessel Bumpers

44. Analysis Assumptions and Methodology
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 material and weld allowable limits set forth by the ASME Pressure Vessel Code
Code limits are for guidance and not a hard requirement

45. Helium Vessel Support Loads
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)

46. Pressure Vessel Code Stress Limits
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 based on guidelines in PV code
Tensile and shear stresses are combined using von Mises formulation

47. Lower He Vessel Axial Load Blocks (weld)
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 mm2 (2.42 in2)
Weld I: 4.40x105 mm4 (1.06 in4)
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

48. Lower He Vessel Axial Load Blocks (mat’l)
Calculation Details
Material: 304L stainless steel
Net axial load: 8.7 kN (1962 lb)
Moment arm: 36 mm (1.4”)
Block A: 2903 mm2 (4.50 in2)
Block I: 3.51x105 mm4 (0.84 in4)
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)

49. Lower He Vessel Invar Rods and Nuts
Rod Calculation Details
Material: Invar ½” all thread
Net axial load: 4.4 kN (981 lb)
Rod stress area: 91.5 mm2 (0.142 in2)
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 mm2 (0.33 in2)
(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

50. Lower He Vessel Axial Stanchions
Calculation Details
Material: 304L stainless steel
Net axial load: 4.4 kN (981 lb)
Moment arm: 95 mm (3.8”)
Area: 1976 mm2 (3.06 in2)
Mom. area I: 3.25x105 mm4 (0.78 in4)
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)
Peak Stress
One stanchion can carry the full load if machining and assembly tolerances lead to unequal loading

51. Lower He Vessel Axial Stanchion Bolts
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 mm2 (0.27 in2)
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)
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
One bolt in one stanchion can carry the full load if machining and assembly tolerances lead to unequal loading

52. Lower He Vessel Axial Stanchion Friction
Calculation Details
Material: 18-8 stainless steel
Bolt size: M16-1
Stress area: 175 mm2 (0.27 in2)
Yield stress: 276 MPa (40 ksi)
Bolt load: 24.1 kN ( % 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

53. He Vessel Clevises for Vertical Struts (weld)
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 mm2 (2.89 in2)
Weld I: 10.4x105 mm4 (2.50 in4)
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

54. He Vessel Clevises for Vertical Struts (mat’l)
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 mm2 (0.49 in2)
(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 Bending Stress Calculation
Moment arm: 24 mm (0.94”)
(at base of rod end cut-out)
Area: 1288 mm2 (2.00 in2)
Mom area I: 1.76x105 mm4 (0.43 in4)
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)
Clevis Pin Calculation Details
Pin diameter: 19.1 mm (0.75 in)
Pin area: 285 mm2 (0.442 in2)
Shear stress: 34.4 MPa (5.00 ksi)
Equivalent stress: 59.7 MPa (8.65 ksi)

55. He Vessel Vertical Support Struts
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 mm2 (0.373 in2)
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: 0.647x105 mm4 (0.016 in4)
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)

56. He Vessel Top Plate Support (horiz wall weld)
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 mm2 (1.41 in2)
Weld I: 5.36x105 mm4 (1.29 in4)
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)

57. Vessel Top Plate Support (horiz wall bracket)
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 mm2 (1.06 in2) 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)
Welds
Bolt
Added
clevis
Clevis Shear Pullout Calculation Details
Shear pullout area: 242 mm2 (0.375 in2)
Shear stress: 27.6 MPa (4.00 ksi)
(load spread over 4 areas at each clevis)
Equivalent stress: 35.1MPa (5.10 ksi)

58. He Vessel Top Plate Support (vertical wall)
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 mm2 (2.06 in2)
Weld I: 3.81x105 mm4 (0.916 in4)
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

59. Helium Vessel Cover Plate Weld Analysis
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)
Cover
Weld
Vessel frame

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

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

62. Bus Duct Thrust Support Analysis (weld clamp)
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

63. Bus Duct Thrust Support (thrust plate weld)
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 mm2 (1.46 in2)
Weld mom. Area I: 1.61x105 mm4 (0.388 in4)
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

64. 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 mm2 (2.77 in2)
Mom area I: 2.40x104 mm4 (0.058 in4)
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

65. Bus Duct Thrust Support (D1 side)
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 mm2 (2.77 in2)
Mom area I: 2.40x104 mm4 (0.058 in4)
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)
Thrust
plate
Material stress exceeds allowable stress dictated by PV code but is well within material strength limits
Short, double
Plate design

66. XB Line/Surge Tank Load Analysis
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)
1.0 kN
.65 kN
4.0 kN
3.4 kN
.80 kN
1.0 kN
.65 kN
3.4 kN
.44 kN
4.0 kN

67. XB Line/Surge Tank Stress Analysis
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)
1.0 kN
3.4 kN (worst case
axial rod load)
.80 kN
Horizontal supp’t
weld 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)
Allowable stress: 115 MPa (16.7 ksi)
Weld efficiency factor: 0.55
Net allowable stress: 63.3 MPa (9.19 ksi)
1.0 kN
Worst case vertical
tab weld load

68. XB Line/Surge Tank Stress Analysis
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 mm2 (0.625 in2)
Mom area I: 5.42x103 mm4 (0.013 in4)
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)
3.4 kN (worst case
axial rod load)
Bending stress on
forked bracket
3.4 kN
Material stress exceeds allowable stress dictated by PV code but is well within material strength limits

69. XB Line (w/o surge tank) Load Analysis
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 mm2 (1.69 in2)
Mom area I: 8.23x103 mm4 (0.020 in4)
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)
2.0 kN
4.0 kN
Circular
thrust
plate
Material stress exceeds allowable stress dictated by PV code but is within material strength limits

70. Bumpers
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) => lb per anchor
9770lb (43.5kN)
13”
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
10”
Prying force
Pivot point
24 April 2007
DFBX

71. Bumper FEA model Local Max stresses at 136 MPa Yield at 190Mpa
24 April 2007
DFBX

72. DFBX Shipping
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.
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.
24 April 2007
DFBX

73. DFBX Summary
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

74. DFBX Conclusion
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

75. Future Activities
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