rf-structures mock-up fea assembly tooling v. soldatov , f. rossi, r. raatikainen 27.6.2011
DESCRIPTION
RF-Structures Mock-Up FEA Assembly Tooling V. Soldatov , F. Rossi, R. Raatikainen 27.6.2011. INDEX. EBW tooling for PETS Introduction General description Assembly on tooling Transportation EBW process FEA Loading and Boundary Conditions Results Conclusions - PowerPoint PPT PresentationTRANSCRIPT
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RF-Structures Mock-Up FEA Assembly Tooling
V. Soldatov, F. Rossi, R. Raatikainen27.6.2011
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INDEX
1. EBW tooling for PETS
Introduction • General description• Assembly on tooling• Transportation• EBW process
FEA• Loading and Boundary Conditions• Results
Conclusions
2. Brazing tooling for AS
Introduction• General description• Assembly on tooling• Brazing process
FEA
• Loading and Boundary Conditions• Results
Conclusions
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1. EBW tooling for PETS
Introduction • General description• Assembly on tooling• Transportation• EBW process
FEA• Loading and Boundary Conditions• Results
Conclusions
2. Brazing tooling for AS
Introduction• General description• Assembly on tooling• Brazing process
FEA
• Loading and Boundary Conditions• Results
Conclusions
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General description
Closure assy 1
Mock-up (damped) assembly
Minitank (short) assembly
Middle connection assy
614.35 mm
271.5 mm
202 mm
Closure assembly 2
FrictionalcontactFrictional
contactEBW EBW
EBW EBW
Minitank assembly
NO
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Assembly on tooling
Bearing
Upper eye-bolt
Upper bolt
Upper cap cover
Lateral eye-bolt
Holding-device
Lower cap cover
Lower bolt
Lateral eye-bolt
Nut
Threaded rod
Nut• Bearing: allow EBW tooling rotation around its axis, once it is
positioned on the EBW machine.
• Upper cap cover: apply clamping force to PETS unit, once the nut is screwed on the threaded rod.
• Upper bolt: fix upper cap cover and closure assy 2.
• Eye-bolts: for lifting and handling.
• Threaded rod (M16): connection between the upper and the lower cap cover.
• Lower cap cover: sustain PETS unit during the assembly on the tooling.
• Lower bolt: fix lower cap cover and closure assy 1.
• Nut (M16): after it is screwed using a torque spanner, a compressive axial load is applied to PETS units (while the rod has tensile stresses).
• Holding device: fix axial and angular position between minitanks and adapter disks.
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Assembly on tooling
1. The second mock-up (damped) assembly is
inserted into the middle connection assy
2. Minitank assembly is positioned
3. Closure assy 1 is positioned
4. Threaded rod is inserted and the
upper cap cover is positioned
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Assembly on tooling
6. Clamping force is applied using a torque spanner5. The holding device is fixed
1st FEM analysis: calculate gap variation in function of the applied load
7. Tack welding
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Transportation
8. Rotation and transport to the EBW machine.
9. The holding device is removed.
FrictionalcontactFrictional
contact
EBW EBW
EBW EBW
2nd FEM analysis: calculate the clamping force necessary to maintain the contact in the designed area (friction forces between adapter disks and mock-up bars are greater
than mock-up bars weight)
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Clamping force vs. Tightening torque
Ma [Nmm] = Fv ·(0.159·P + 0.578·d₂·µg + 0.5·dKm·µk) = ~ 3·Fv [N]
CLAMPING FORCE
(Fv)
TIGHTENING TORQUE
(Ma)
M16
• P = thread pitch (2 mm)• d2 = thread diameter (16 mm)• µg = friction coefficient of the thread (0.15)
• dKm = average diameter of the bolt head (22.16 mm)• µk = friction coefficient of the bolt head (0.15)
dkm
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EBW process
Wel
ding
BearingChuckdriven by the
welding machine
FixedV-support
Ground
FEA
Aim
1. Calculate the axial force necessary to hold the assembly on the tooling during the EBW process2. Calculate the deformation involved in the process
Hypothesis
The problem is considered as a static structural and no dynamical effects were taken into account (e.g. rotational speed 0.004 rad/s)
Model and initial clamping force range for further studies
FE-model including:
-All copper parts (Cu-OFE) of PETS-St.Steel PETS flanges, minitank and tooling
The initial gap of 50 µm is reduced to zero. High deformations of minitanks occur.
Friction forces between adapter disks and mock-up bars are lower than mock-up bars weight (the contact is not in the designed area)
Maximum 50 kN
Minimum 0.3 kN
Clamping force
Fixed Gravity
Gravity
1st position 2nd position
Fixed(Motor chuck)
Loading & Boundary Conditions
Bearing condition-The selected ball bearing allows 10 (0.17°) of rotation-Rotation due to gravity is allowed-Translation d.o.f. is fixed
Results – Axial force of 1 kN
Δgap max 1 µm
Δdeflection 10.5 µm
Results – Axial force of 2.5 kN
Δgap max 2 µm
Δdeflection 10.8 µm
Max. Stress 3 MPa
Conclusions
On the basis of FEA performed, the selected clamping force is 2.5 kN, which corresponds to a tightening torque of 7.5 Nm
According to the results, the reduction of initial flanges gap (50 µm) due to the applied load is negligible.
The results show that larger clamping forces do not have significant influence on the transversal deflection of PETS. Anyway, this elastic deflection will be completely recovered once the structure is supported on the designed supports for TM0.
The highest stresses occur around the contact area close to the edge inside the adapter disk. For a clamping force of 2.5 kN the maximum value is less than 3 MPa (σY = 69 MPa)
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1. EBW tooling for PETS
Introduction • General description• Assembly on tooling• Transportation• EBW process
FEA• Loading and Boundary Conditions• Results
Conclusions
2. Brazing tooling for AS
Introduction• General description• Brazing process• Assembly on tooling
FEA• Loading and Boundary Conditions• Results
Conclusions
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General description
Cooling circuit
Vacuum flange
RF flange
ManifoldInterconnection
flange
RF waveguide
Accelerating structure
Super-accelerating structure
Target sphere
2031
484
334
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Brazing process BRAZING
(Au/Cu 25/75, 1040 °C)1. WFM WG cover + WFM WG body (x32=4x8)2. Waveguide damping interface half 1 + half 2 (x32=4x8)3. Stack type 1 (x6)4. Stack type 2 (x1)5. Stack type 3 (x1)6. Manifold cover (tank int.) + vacuum tube P1 (x8)7. Manifold small cover 3 + small cover 3 insert (x32=4x8)
TIG WELDING1. Manifold cover 2 assembly (x8)
MACHINING1. WFM WG brazed (x24=3x8)2. WG damping interface (x16=2x8)
BRAZING(Au/Cu 25/75, 1040 °C)
1. Manifold (hor) assembly (x8=1x8)2. Hor. manifold (mirrored) assembly (x8=1x8)3. Vert. manifold assembly (x16=8x2)
BRAZING(Au/Cu 35/65, 1020 °C)
1. Structure type 1 (x6)2. Structure type 2 (x1)3. Structure type 3 (x1)
BRAZING(Au/Cu 50/50, 980 °C)
1. Brazed stack 1 + AS cooling fitting adapters2. Brazed stack 2 + AS cooling fitting adapters
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Brazing process
900 °C
1020 °C
Temperature history
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Assembly on tooling
Rod
Nut
Lower plate
Lateral support
Lateral spring
Lateral plate
Upper support
Upper spring
Wedges
• Lower plate (graphite): support the assembly during alignment operations and brazing cycle.
• Wedges (ceramic): allow small adjustment of manifolds in the vertical direction.
• Lateral springs (graphite): apply an horizontal force to the manifolds through the lateral plates and allow thermal expansion of the assembly during the brazing cycle (k=20 N/mm).
• Lateral supports (stainless steel): support the springs.
• Upper spring (graphite): apply a vertical force on the manifolds through the upper support and allow thermal expansion of the assembly during the brazing cycle.
• Rod (stainless steel): connect upper support and lower plate.
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Assembly on tooling
1. Graphite plate 2. Disks stack 3. Wedges 4. Manifolds
5. Lateral supports, plates and springs
6. Upper support 7. Rod 8. Upper spring and nut
Tooling for the 1st brazing step
FEA
A static thermal and structural analysis with a temperature variation from 20 °Cto 1020 °C was carried out for the accelerating structure
The thermal expansion is constrained only by the springs, which are situated on the opposite sides of the fixed lateral support
All the connections were considered ideally frictionless to reduce the computational time
Fixed surfaces connected to the lateral support (without springs)
Free surfaces constrained by the springs
Supported on the ground
For the springs a constant stiffness of 20
N/mm was used
Results – thermal expansion
xyz
Max. in x-direction 4.6 mm Max. in y-direction 7.2 mm
Max. in z-direction 5.3 mm
Results – stresses
Max. 0.1 MPa
Stress due to thermal expansion
On the basis of the FEA the displacements and the stresses due to thermal expansion have been calculated
The transversal displacement of the manifolds is approximately 5 mm The axial displacement of the whole structure is approximately 5 mm During the brazing process the calculated stresses are below the copper yield
strength at 1020 °C (σY = 7.5 MPa)
Future work
- Transient thermal analysis to model the temperature history- Thermal and structural simulations for the brazing of 4 AS - Structural analysis for the AS intermediate EBW tooling
Conclusion