engineering division 1 vacuum vessel production readiness review july 29, 2009 allan demello...
TRANSCRIPT
Engineering Division1
Vacuum Vessel Production Readiness
Review
July 29, 2009
Allan DeMelloLawrence Berkeley National Lab
Muon Ionization Cooling Experiment (MICE)
Radio Frequency/Coupling Coil Module (RFCC)
Engineering Division2
MICE Beamline
Engineering Division3
Radio Frequency/Coupling Coil Module (RFCC)
Engineering Division4
RFCC Quarter Section View
Engineering Division5
Vacuum Vessel Exploded
Major Components of the Vacuum Vessel
Engineering Division6
• Fabricate of vacuum vessel in 3 sections – two 316L stainless steel flanged sections and one 316L stainless steel central sleeve
• Assemble 3 vacuum vessel sections to the coupling coil (in appropriate fixturing)
• Verify alignment of all vacuum vessel components• Weld all joints and gussets• Weld on the vacuum pump manifolds and RF
feedthroughs• Leak check vacuum vessel
Overview of Fabrication Procedure
Engineering Division7
Rolled Cylinder
Engineering Division8
Fabrication of Vacuum Vessel Flanged Section
Engineering Division9
Vacuum Vessel to Coupling Coil Gussets
•Remove vessel section from the coupling coil and complete the welding of the gussets to the vessel
Tack weld a stainless steel bar across the gusset pairs to help maintain their position
Align gussets to coupling coil and tack weld to vacuum vessel
Engineering Division10
Final Machining of Vessel Section
Engineering Division11
Weld on Strut Mounting Posts
Engineering Division12
Vacuum Vessel Central Sleeve
•Precision machined central sleeve•5.08mm (0.200 in.) wall thickness•1384.93mm O.D.•1374.77mm I.D.
Engineering Division13
Assemble Vacuum Vessel and Weld
Engineering Division14
Weld on Manifold and Feedthroughs
Vacuum Vessel and Coupling Coil Assembly
Engineering Division15
Vacuum Vessel Assembly Fixturing Scheme
Engineering Division16
Vacuum Vessel Analysis
Engineering Division17
• Calculate stress for thin walled pressure vessel• Analyze vacuum vessel per 2007 ASME Boiler and
Pressure Vessel Code VIII, Division 1• ANSYS analysis for vessel with external pressure• ANSYS analysis for the 50-ton magnetic load• ANSYS analysis for tilting to horizontal position• ANSYS analysis for lifting from four points
Vacuum Vessel Analysis
Engineering Division18
Thin Walled Cylinder Stress - 0.200 inch
Engineering Division19
Thin Walled Cylinder Stress - 0.500 inch
Engineering Division20
Length
÷ O
uts
ide D
iam
ete
r =
L/
Do
Outside Diameter ÷ Wall Thickness = Do/t
Factor A
Factor A
Fact
or
B
Charts used to find Factor A and Factor B which are used in ASME Boiler and Pressure Vessel Code Calculations
ASME Boiler and Pressure Vessel Code
Engineering Division21
Minimum Wall Thickness(2007 ASME Boiler and Pressure Vessel
Code)
Engineering Division22
Design Verification – External Pressure(2007 ASME Boiler and Pressure Vessel
Code)
Engineering Division23
Design Verification – Internal Pressure(2007 ASME Boiler and Pressure Vessel
Code)
•A burst disc will be installed on the vessel to avoid the possibility of over-pressure (25psi max)
Engineering Division24
Design Verification – External Pressure (1/3 Vessel)(2007 ASME Boiler and Pressure Vessel
Code)
Engineering Division25
Design Verification – External Pressure(2007 ASME Boiler and Pressure Vessel Code)
Engineering Division26
ANSYS Analysis
ANSYS Analysis
Engineering Division27
Vacuum Vessel w/o Coupling Coil
Engineering Division28
Model of Vacuum Vessel for ANSYS
•14.7 psi external pressure applied to stainless steel vessel
Engineering Division29
ANSYS Results - Equivalent Stress
•14.7 psi external pressure applied to stainless steel vessel•1888 psi maximum equivalent (von Mises) stress•Maximum allowable stress for 316L stainless steel from ASME Boiler and Pressure Vessel Code is 16,700 psi•Weld efficiency of 60% reduces the maximum allowable stress to 10,020 psi•With the de-rated welds the maximum stress is 5.3 times less than the maximum allowable stress
Engineering Division30
Model - Vessel With Gussets Added
•14.7 psi external pressure applied to stainless steel vessel
Engineering Division31
ANSYS Results - Equivalent Stress
•14.7 psi external pressure applied to stainless steel vessel with gussets•2041 psi maximum stress•Weld efficiency of 60% reduces the maximum allowable stress to 10,020 psi•With the de-rated welds the maximum stress is ~5 times less than the maximum allowable stress
Engineering Division32
Bellows Bridge Bolts
•Bridge bolts are needed to transmit the potential 50-ton magnetic force when the magnet quenches
Bridge bolts – exterior view
Bridge bolt – section view
•36 - ten millimeter bolts will bridge the RFCC to AFC bellows
Bellows pulled back for module clearance
Engineering Division33
Model – Vessel with Bridge Bolts
36 bolts in flange
•Stand fixed at base pads•Vessel fixed at bolt face•50-ton load applied to coupling coil
Engineering Division34
50 Ton Magnetic Force -36 Bridge Bolts
• A 50 ton force is applied to the coupling coil• The vacuum vessel has an increased density to simulate the presence of the cavities• 36 bridge bolts per side to transfer the load to the rest of the MICE beamline.• von Mises max
stress of 32,263 psi on bolt cross section
• Strain hardened 316L stainless steel bolts which have a yield strength of 100,000 psi (minimum) will be used to bridge the bellows
Engineering Division35
Tilting of Vacuum VesselThe vacuum vessel will be tilted from the vertical (operational) position to the horizontal (shipping) position. It will be tilted back again to the operational position in the U.K.
RF cavities are removed for shipping
Engineering Division36
ANSYS Analysis - Tilting of Vacuum Vessel
• The vacuum vessel is modeled in ANSYS to simulate hanging from 2 of the pick points. • The cavities are assumed to be removed. • Ends of vacuum vessel are capped with 0.375 thick aluminum• The force of gravity is applied
6867 psi equivalent stress is well below yield stress for 316L stainless steel of 42000 psi
Engineering Division37
Anticipating the possibility that the complete RFCC module will be lifted using the 4 pick points provided for tilting the assembly - an ANSYS analysis of the lifted assembly was done
Lifting of RFCC Assembly
Engineering Division38
Lifting the RFCC Assembly – ANSYS Results
10161 psi equivalent stress is well below yield stress for 316L stainless steel of 42000 psi
• The vacuum vessel is modeled in ANSYS to simulate hanging from the 4 pick points. • The cavities are assumed to be in place. • Ends of vacuum vessel are capped with 0.375 thick aluminum• The force of gravity is applied
Engineering Division39
• Because of the tight interface between the O.D. of the vacuum vessel and the I.D. of the coupling coil the vacuum vessel is assembled from three major parts
• The two flanged section are fabricated in several steps to minimize the distortion of the welding
• The central sleeve is precision machined to guarantee it will fit into the coupling coil I.D.
• Analysis verifies the ability of the vacuum vessel to withstand the vacuum loads
• Strain hardened 316 stainless steel bridge bolts will be needed to transfer the magnetic loads through the bellows joint
• Tilting and lifting are possible with this design
Summary
Engineering Division40
Thank You