Long racetrack supporting structure

1
Long racetrack supporting structure

• Paolo Ferracin and Dan Cheng
• LARP Collaboration Meeting
• LBNL
• April 26 - 28, 2006

2
Outline

• Introduction
• Magnet design
• Assembly and pre-loading
• Magnetic analysis
• Mechanical analysis
• Test plan
• Current status and next steps

3
Introduction

• Task goals
• Provide supporting structure for test of 4 m long
  racetrack coils
• Develop a shell-based supporting structure for
  long magnets
• Steps
• Design, procure the structure
• Define a procedure for assembly and disassembly
• Test structure at LBNL with dummy coils
• Check uniform load with
• Strain gauges mounted on the shell
• Pressure sensitive films
• Ship structure to BNL
• Design based on the support structure for the SM
  program

4
Outline

• Introduction
• Magnet design
• Assembly and pre-loading
• Magnetic analysis
• Mechanical analysis
• Test plan
• Current status and next steps

5
LR cross-section

• With respect to SM design
• Aluminum shell
• Larger diameter 305 mm
• Thicker iron yokes
• Bigger yoke gaps
• Simplified iron pads
• Thicker stainless steel skins
• 2 bladders and 4 loading keys for assembly and
  pre-load
• 2 pull shims for bladder removal

6
LR 3D design

• Aluminum shell
• Single piece
• Length 3.6 m
• Iron yokes
• 50 mm thick laminations
• Iron pads
• Half length (1.8 m)
• Stainless steel skins
• Full length (3.6 m)
• Bladders
• Half length (1.8 m)
• Keys and shims
• Half length (1.8 m)

7
Outline

• Introduction
• Magnet design
• Assembly and pre-loading
• Magnetic analysis
• Mechanical analysis
• Test plan
• Current status and next steps

8
Assembly-related components

• Handling rafts can be configured for installation
  operations as well
• Installation beam

9
Assembly Process

• Raft and bottom cradles placed onto 25 of
  granite/surface table
• Aluminum shell is placed into cradles
• Upper raft is configured into installation
  fixture

10
Assembly Process

• Cantilever portion of installation raft is then
  inserted into the empty aluminum shell
• Yoke half lamination is assembled on non-inserted
  portion of the installation beam
• Yoke half is inserted into the shell

11
Assembly Process

• Raft is disconnected and reconfigured
• Pull shims inserted
• Compact cylinders are pressurized to 300 psi
• Applies small load keep yoke from shifting during
  rotation operation
• Rotate assembly
• Two-crane (or main/aux. hook) operation
• Or rotation wheels
• Remove top raft
• Bleed pressure

12
Assembly Process

• Reconnect installation beams to handling raft
• Pull assembly beam from shell internals
• Remove internal cradle supports
• Reinsert installation beam
• Rinse, lather, repeat
• (Assemble 2nd yoke half, insert)

13
Assembly Process

• Pressurize cylinder manifold to 300 psi
• Insert gap keys (and necessary shims)
• Bleed cylinder pressure
• Remove installation beam from center
• Yoke halves are now only resting on gap keys

14
Assembly Process

• Reconfigure installation raft
• Replace beam standoffs
• Remove cantilever installation beam

15
Assembly Process

• Align installation beam slots to yoke key slots
• Insert coil pack onto beam w/keys

16
Assembly Process

• Insert pull shims with bladders
• Load yokes with bladder pressure
• Insert necessary shims
• Remove gap keys, etc. from between yokes
• Bleed HP

17
Outline

• Introduction
• Magnet design
• Assembly and pre-loading
• Magnetic analysis
• Mechanical analysis
• Test plan
• Current status and next steps

18
2D magnetic analysisFlux lines and peak field

• Common-coil (quadrupole) flux line profile
• Peak field located in the inner surface of the
  coil, approximately between turn 11 and turn 13.

19
2D magnetic analysisMagnet parameters

• Jc (4.2 K, 12 T) 2800 A/mm2
• Cu/SC 0.9
• Bpeak (4.2 K) 12.2 T
• Iss (4.2 K) 10.8 kA
• Stored energy (4.2 K) 86 kJ/m
• Inductance (4.2 K) 1.5 mH/m

20
3D magnetic analysisField in the ends

• The field decreases from 12.2 T at the center to
  11.6 T at the end of the straight section
• In the end region, the field further decreases to
  11.0 T

21
Outline

• Introduction
• Magnet design
• Assembly and pre-loading
• Magnetic analysis
• Mechanical analysis
• Test plan
• Current status and next steps

22
2D mechanical analysisLorentz forces

• At short sample current
• Fx (quadrant) 1903 kN/m
• ?x 62 MPa
• Fy (quadrant) - 9 kN/m
• ?y lt 1 MPa

23
2D mechanical analysisCoil horizontal stress

• After cool-down
• About 30 MPa coil pre-stress

• At full field
• 75 MPa of coil max. stress

24
2D mechanical analysisTolerance analysis

• Tolerance of the components
• Shell ID
• -0.000 / 0.0025
• Yoke OD
• -0.003 / 0.000
• Yoke key slot
• - 0.002/ 0.002
• Pad thickness
• -0.003 / 0.003
• Total range
• -0.008 / 0.008

25
3D mechanical analysisMechanical model

• 3D geometry
• Full length
• Interaction between shell and yoke in the axial
  direction
• Straight section of 300 mm
• Effect of axial Lorentz forces on the contact
  area coil-island

26
3D mechanical analysisContraction of aluminum
shell

• 4 m long shell
• Shell azimuthal stress at 4.3 K
• ?? 150 MPa
• Frictionless model
• Shell z contraction 9.5 mm
• (ashell lshell) (?? / Eshell ? lshell)
• Yoke z contraction 3.9 mm
• (a yoke lyoke)
• Relative ?z shell-yoke 5.6 mm
• Friction model (µ 0.2)
• Shell z contraction 5.7 mm
• Yoke z contraction 4.2 mm
• Relative ?z shell-yoke 1.5 mm

Friction 0.0
Friction 0.2
27
3D mechanical analysisCoil-island contact region

• Frictionless model
• After cool-down
• Coil ?z 20 MPa
• Island ?z - 50 MPa
• Fz contact 20 kN
• Still contact at high field

28
3D mechanical analysisCoil-island contact region

• Friction model
• After cool-down
• Fz contact 10 kN
• Friction is limiting axial motion
• Still contact at high field

29
Outline

• Introduction
• Magnet design
• Assembly and pre-loading
• Magnetic analysis
• Mechanical analysis
• Test plan
• Current status and next steps

30
Test plan

• Insertion of pressure sensitive films
• Dummy coils skins
• Load keys yoke/pads
• Strain gauges
• Mid-plane (both sides)
• 5 axial locations
• Y and Z directions
• Temperature compensators
• Total 40 gauges
• Test plan
• Pressurize bladders and insert keys in several
  steps
• Monitor stress level and uniformity
• Inspect pressure sens. films

31
Outline

• Introduction
• Magnet design
• Assembly and pre-loading
• Magnetic analysis
• Mechanical analysis
• Test plan
• Current status and next steps

32
Current status (I)

• Engineering design of all the components
  completed
• Magnetic analysis
• Computation of peak field, load line, and field
  in the ends
• Mechanical analysis
• Stress in the coil after cool-down and at high
  field
• Effect of fabrication tolerances
• Sliding between shell and yoke
• Contact coil-island during excitation
• Assembly procedure defined
• Procurement
• Aluminum shell, tie rods, dummy coils available
• Yoke and pads by the end of May

33
Current status (II)
34
Next steps

• May
• Finalize handling structure design detail
  drawings
• Handling rafts (detail drawings in progress)
• Cradles (detail drawings in progress)
• Winch mounts pulling structure (to be designed)
• Instrument shell with strain gauges
• June - July
• Magnet assembly
• Load test