Mechanical Design of LQC

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Mechanical Design of LQC

• I. Novitski and R. Wands

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LQC Design and Model
Skin
Yoke
Collar
Coil
Control spacer
Near Splice
Coil midplane shim
Body area
LJ area
Splice area
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Loads and Boundary Condition

• 1. Assembly at room temperature 300K

• Prestress in the coil during collaring generates
  at midplane by coil-to-coil interference

• During skin welding the yoke-to-collar
  interference at the coil parting plane compresses
  coil radially

• 2. Cool down from 300K to 1.9K

The yoke outer mid-plane gap is open after skin
welding and remains open after cool-down.
Peak stress lt 150 MPa in all conditions (G up to
240T/m) No tension at the pole (best
target) Tension at the pole lt 20 MPa on all
elements (acceptable target). Stress in all
structural elements should be below yield point.

• 3. LF at 1.9K , G240T/m

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Material Properties
All data from HFM dipole with correction for
thinner cable insulation
Load-Unload-Reload Tests
Data from HFM Dipole
Cyclic Loading Tests
Hand book data
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Collaring, LQC Model (Body), Mp0.35mm,Rsh0.1mm
300K
106MPa
Coil saz
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TQC Model (Body) with Ti poles, no
slotMp0.35mm,Rsh0.1-0.125-0.1mm,
St0-0,Sk0.3mm
149MPa/134MPa
165MPa/144MPa
165MPa
-82mm
-120mm
61mm
-274mm
-93mm
-300mm
Bmax 233T/m
300K
1.9K
-204mm
58mm
-95MPa
-105MPa
-172mm
2MPa
-95MPa
-105MPa
-50MPa
Coil saz 300K134MPa, 1.9K144MPa, G
240T/m165MPa
ExEy30044GPa, ExEy444GPa, coil
anisotropic-plasticity
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Fskin
TQC-02 Force Balance
FSu
Fpu
Fcollar
Fmp
measured
Fpd
calculated
FSd
Fskin
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FEA Results
Stresses in LQC Coils and Components (MPa)
The cable insulation and Nb3Sn strands are under
maximal compressive load 140MPa at 300K and
160MPa at 2K.
Add sensitivity data
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The 3-D FE Model
Endplate for axial preload
Iron and skin
Coils and endparts
Collars
Courtesy by R. Wands
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TQC 3D Mechanical Analysis
3D FEA of structures was completed at both LBNL
and FNAL. Analysis indicates that, depending on
input parameters and end loading, separation
between end parts and first turn of coils of
between 20um and 200 um can take place when the
magnet is powered if the design end load of 14kN
is applied.
Effect of this separation on training behavior is
not clear. There is evidence from racetracks at
LBNL that a correlation exists between gaps and
training. Many magnets built and tested at
Fermilab, both Nb3Sn and NbTi, with minimal and
no end loading, do not have excessive training
quenches in the ends.
Total load per end from Lorenz forces at 12000
amps is estimated to be 280 kN. Total load
increase on bullets in TQC01 from 0-12000 amps
was about 50 kN, or 15-20 of the total force.
Courtesy by R. Wands
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Simplification of Coil Behavior at Magnet Assembly
20GPa
Uncertainty in MP shimming
Overestimation
Plasticity
Underestimation
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Plasticity
20GPa
44GPa
Elasticity
Plastic deform.