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October 2001Pixel Week N. Hartman LBNL 2
ATLAS Pixel Detector
Current Design Status• FEA Modeling
– Design Variables– Recent Analysis Results– Low Stiffness Forwards– SCT Reaction Loads– Comparison to SCT analysis
• Testing– Friction Tester Constructed– Slider Materials Delivered– Carbon Samples Ordered
• Prototyping Plans– One Foot Sample Mandrel will be fabricated– Initial Autoclave Tryout Run Will Be Completed Soon– Mandrel Quotes Received
October 2001Pixel Week N. Hartman LBNL 3
ATLAS Pixel Detector
Design Variables
• Flange Material (PEEK or Carbon Fiber)• Longitudinal Ribs• Hoop Stiffeners (in Forwards)• End Plug (PP1 panel)• Flange Shape• Barrel Constraints (ties across SCT diameter)• Service Mass (incorporated in forward shell material)• Fiberglass Forward Shells• 1 or 2 Z Constraints• Forward End Constraints
October 2001Pixel Week N. Hartman LBNL 5
ATLAS Pixel Detector
FEA Model – Important Features
Bolt flanges
Sct mount padsEnd Plugs (1 mm equiv. carbon sheet)
Hoop Hat Stiffeners(section view)
30
4510
End Support
End Supports
October 2001Pixel Week N. Hartman LBNL 6
ATLAS Pixel Detector
Support Tube – Flange Details
Flange x-section detail
End view of barrel flange(forward flanges have no Mount bosses and no gas seal features – see below)
barrelforward
Constraint Areas
October 2001Pixel Week N. Hartman LBNL 7
ATLAS Pixel Detector
Flange Bolt Spacing CalculationsFlange is conservatively modeled as a simple beam:
- modeled as guided beam with length of bolt spacing/2- cross section is assumed to be smallest flange section (forward)- flange force given by support tube loads (next slide)
L
L/2
Flange Load
Number of Bolts Bolt Spacing (m) Delta (microns)32 0.046 11.4540 0.037 5.8648 0.031 3.3956 0.026 2.1464 0.023 1.43
October 2001Pixel Week N. Hartman LBNL 8
ATLAS Pixel Detector
Flange Bolt Spacing Calculations (cont.)
Forward TubeBarrel tubeAssumed rigid
ForwardAnd servicesmass
Flange load=(Forward Load*(L/d))
Tube Deflection is calculated based on following assumptions:- forward tube pivots rigidly about bottom of flange- total forward tube mass (including services) is cantilevered- full flange load is taken by upper bolts only (3 bolts)- all structures rigid
Frequency is estimated based on tube deflection using f=(1/2 * (g/)1/2)
Flange delta
tubeDeflection
( )
Number of Bolts Delta Tube (microns) Frequency32 64.55 62.6440 33.05 87.5548 19.13 115.0856 12.04 145.0264 8.07 177.18
desire frequency > 100 Hznumber at left assumes no ribs -ribs act like bolt constraints -evenly spaced ribs allow half the number of boltsDesign for 24 bolts in flange
d
L
October 2001Pixel Week N. Hartman LBNL 9
ATLAS Pixel Detector
Flange Face (machined layup)
Flange base(Layup)
Stiffeners(layups)
Support Flange Bonded Assembly
T-nuts(bonded)
Old design - now gone forindependent thermal barrier
October 2001Pixel Week N. Hartman LBNL 11
ATLAS Pixel Detector
PST Position in Inner Detector
PIXEL SUPPORT TUBE
SCT
TRT
ID Vee Rail
ID Flat Rail
Side C Side A
View from top—allTube Supports are
Horizontal and Co-planar
Properties TBD
Constraint TBD
Support Positions are shown,But constraint conditions areNot indicated here.
+Z
+X
+Y Vertical
Agreed Support Positions outside PST
PST Support Conditions Under Investigation
October 2001Pixel Week N. Hartman LBNL 12
ATLAS Pixel Detector
Constraint Conditions: Fixed/Free ends
Side C Barrel Side a
Side C Barrel Side a
Fixed X
Fixed XYZ
Fixed Z
Fixed Y
Fixed Forward Ends
Free Forward Ends
+Z
+X
+Y Vertical
October 2001Pixel Week N. Hartman LBNL 13
ATLAS Pixel Detector
Model Properties
Material Model Material Location
Fiber Modulus (GPa)
Bulk Modulus (GPa)
Density(kg/m3)
High Mod. Carbon
Shell, Hat Stiffeners
420 98 1650
Ultra High Mod. Carbon
Flanges(Option 1)
560 126 1650
PEEK (graphite filled)
Flanges(Option 2)
N/A 3.5 1500
Glass (Quartz) Forward Shells 91 21 1800
HM Carbon (incl. service mass)
Forward Shells 420 98 12300
Glass (incl. service mass)
Forward Shells 91 21 12450
October 2001Pixel Week N. Hartman LBNL 15
ATLAS Pixel Detector
Original Model
Side C Barrel Side aSide C Barrel Side a
ModelDescription Mode 1 Mode 2 Mode 3 Mode 4 Mode 1 Mode 2 Mode 3 Mode 4
Original Model 8.9 11.9 17.9 26 12.9 13.7 18 42.1Carbon Flange Material 24.5 41.2 61.5 65.6 54.7 55.6 69.9 72.8
Without Ribs 25.8 44 55.9 62.4 58.5 59.2 67.9 68.5With Hoops and End Plugs 64 114.6 116.5 117.9
Carbon Flange Concept 31.4 48.4 55.3 62.2 88.7 118.6 119 123.6Barrel Constr. Across SCT 51.3 53.8 55.3 62.2 118.8 119 123.6 123.7
Service Mass (13 kg) 26.4 27.7 28.6 32.3 53.1 53.2 54.2 54.2Glass Shells – 1 Hoop 27.4 27.4 27.8 27.9
Glass Shells – 3 Hoops 43.7 43.7 43.8 43.8
Free Forwards Fixed Forwards
Modes in Italics are shells modes , Modes in bold are beam (cantilever) modes.
PEEK Flanges
Longitudinal Ribs
October 2001Pixel Week N. Hartman LBNL 16
ATLAS Pixel Detector
Carbon Flange Material
Side C Barrel Side aSide C Barrel Side a
ModelDescription Mode 1 Mode 2 Mode 3 Mode 4 Mode 1 Mode 2 Mode 3 Mode 4
Original Model 8.9 11.9 17.9 26 12.9 13.7 18 42.1Carbon Flange Material 24.5 41.2 61.5 65.6 54.7 55.6 69.9 72.8
Without Ribs 25.8 44 55.9 62.4 58.5 59.2 67.9 68.5With Hoops and End Plugs 64 114.6 116.5 117.9
Carbon Flange Concept 31.4 48.4 55.3 62.2 88.7 118.6 119 123.6Barrel Constr. Across SCT 51.3 53.8 55.3 62.2 118.8 119 123.6 123.7
Service Mass (13 kg) 26.4 27.7 28.6 32.3 53.1 53.2 54.2 54.2Glass Shells – 1 Hoop 27.4 27.4 27.8 27.9
Glass Shells – 3 Hoops 43.7 43.7 43.8 43.8
Free Forwards Fixed Forwards
Modes in Italics are shells modes , Modes in bold are beam (cantilever) modes.
Carbon Flanges
Longitudinal Ribs
October 2001Pixel Week N. Hartman LBNL 17
ATLAS Pixel Detector
Removing Ribs
Side C Barrel Side aSide C Barrel Side a
ModelDescription Mode 1 Mode 2 Mode 3 Mode 4 Mode 1 Mode 2 Mode 3 Mode 4
Original Model 8.9 11.9 17.9 26 12.9 13.7 18 42.1Carbon Flange Material 24.5 41.2 61.5 65.6 54.7 55.6 69.9 72.8
Without Ribs 25.8 44 55.9 62.4 58.5 59.2 67.9 68.5With Hoops and End Plugs 64 114.6 116.5 117.9
Carbon Flange Concept 31.4 48.4 55.3 62.2 88.7 118.6 119 123.6Barrel Constr. Across SCT 51.3 53.8 55.3 62.2 118.8 119 123.6 123.7
Service Mass (13 kg) 26.4 27.7 28.6 32.3 53.1 53.2 54.2 54.2Glass Shells – 1 Hoop 27.4 27.4 27.8 27.9
Glass Shells – 3 Hoops 43.7 43.7 43.8 43.8
Free Forwards Fixed Forwards
Modes in Italics are shells modes , Modes in bold are beam (cantilever) modes.
No Longitudinal Ribs
PST Rib Comparisons Area (mm^2) Inertia (mm^4) PST Tube 726 1.93E+07
PST Ribs (6) 360 1.92E+07 Tube + Ribs 1086 3.85E+07
October 2001Pixel Week N. Hartman LBNL 18
ATLAS Pixel Detector
Constrain across SCT
Side C Barrel Side aSide C Barrel Side a
ModelDescription Mode 1 Mode 2 Mode 3 Mode 4 Mode 1 Mode 2 Mode 3 Mode 4
Original Model 8.9 11.9 17.9 26 12.9 13.7 18 42.1Carbon Flange Material 24.5 41.2 61.5 65.6 54.7 55.6 69.9 72.8
Without Ribs 25.8 44 55.9 62.4 58.5 59.2 67.9 68.5With Hoops and End Plugs 64 114.6 116.5 117.9
Carbon Flange Concept 31.4 48.4 55.3 62.2 88.7 118.6 119 123.6Barrel Constr. Across SCT 51.3 53.8 55.3 62.2 118.8 119 123.6 123.7
Service Mass (13 kg) 26.4 27.7 28.6 32.3 53.1 53.2 54.2 54.2Glass Shells – 1 Hoop 27.4 27.4 27.8 27.9
Glass Shells – 3 Hoops 43.7 43.7 43.8 43.8
Free Forwards Fixed Forwards
Modes in Italics are shells modes , Modes in bold are beam (cantilever) modes.
October 2001Pixel Week N. Hartman LBNL 19
ATLAS Pixel Detector
Modal Shapes
Hoops and End Plugs New Flange Shape
Barrel Constraints
Modes: 119 / 119 / 124 / 124
October 2001Pixel Week N. Hartman LBNL 20
ATLAS Pixel Detector
Low Stiffness Forwards
Model Fixed Forwards
Description Mode 1 Mode 2 Mode 3 Mode 4
Carbon Shells – 1 Hoop 53.1 53.2 54.2 54.2 Glass Shells – 1 Hoop 27.4 27.4 27.8 27.9 Glass Shells – 3 Hoops 43.7 43.7 43.8 43.8
Additional Hoops
October 2001Pixel Week N. Hartman LBNL 21
ATLAS Pixel Detector
Vibration Results Summary
ModelDescription Mode 1 Mode 2 Mode 3 Mode 4 Mode 1 Mode 2 Mode 3 Mode 4
Original Model 8.9 11.9 17.9 26 12.9 13.7 18 42.1Carbon Flange Material 24.5 41.2 61.5 65.6 54.7 55.6 69.9 72.8
Without Ribs 25.8 44 55.9 62.4 58.5 59.2 67.9 68.5With Hoops and End Plugs 64 114.6 116.5 117.9
Carbon Flange Concept 31.4 48.4 55.3 62.2 88.7 118.6 119 123.6Barrel Constr. Across SCT 51.3 53.8 55.3 62.2 118.8 119 123.6 123.7
Service Mass (13 kg) 26.4 27.7 28.6 32.3 53.1 53.2 54.2 54.2Glass Shells – 1 Hoop 27.4 27.4 27.8 27.9
Glass Shells – 3 Hoops 43.7 43.7 43.8 43.8
Free Forwards Fixed Forwards
Modes in Italics are shells modes , Modes in bold are beam (cantilever) modes.
October 2001Pixel Week N. Hartman LBNL 22
ATLAS Pixel Detector
Reaction Loads On SCT
Model Material FX (N)
FY (N)
FZ (N)
MX (Nm)
MY (Nm)
MZ (Nm)
Carbon - 151 0 253 - -
Glass - 53 0 89 - -
Vertical Bending – Both Ends
Both Ends Bent – 1 Z ConstraintModel Material FX (N) FY (N) FZ (N) MX
(Nm)MY
(Nm)MZ
(Nm)
Carbon 146 - - - 233 -
Glass 52 - - - 83 -Both Ends Bent – 2 Z Constraints
Model Material FX (N) FY (N) FZ (N) MX (Nm)
MY (Nm)
MZ (Nm)
Carbon 297 - 1870 - 536 -
Glass 108 - 468 - 110 -
One End Bent – 1 Z ConstraintModel Material FX (N) FY (N) FZ (N) MX
(Nm)MY
(Nm)MZ
(Nm)
Carbon 390 - - - 623 -
Glass 137 - - - 218 -
Horizontal Bending
October 2001Pixel Week N. Hartman LBNL 23
ATLAS Pixel Detector
Gravity Sag Calculations
Carbon Glass
October 2001Pixel Week N. Hartman LBNL 24
ATLAS Pixel Detector
Comparison to SCT AnalysesSCT Analysis Comparisons
Bend Direction
Load Case FX (N) FY (N) FZ (N)
Y dy1 = dy2 = 2 mm SCT 141 Y dy1 = dy2 = 2 mm Carbon 151 Y dy1 = dy2 = 2 mm Glass 53 Y dy1 = dy2 = 2 mm Projected* 49
X dx1 = dx2 = 2mm SCT^ 325 588 X dx1 = dx2 = 2mm Carbon^ 297 1870 X dx1 = dx2 = 2mm Glass^ 108 468 X dx1 = dx2 = 2mm Projected*^ 118 147
Force Load Case DY (mm)
G Carbon .57 G SCT Carbon .61 G Glass 1.64 G SCT Glass 2.88
• Discrepancies Due To:– Properties (SCT used different tube modulus; barrel modulus and
forward modulus changed to glass)– Loads (pixel detector distributed, not supported on mounts)– Constraints
• Extra Z constraint• SCT intrinsic compliance• Simple instead of complete constraints at Barrel
Projected uses ratioof SCT to our FEA with carbon forward tubes
October 2001Pixel Week N. Hartman LBNL 25
ATLAS Pixel Detector
Slider design - materials testing
• Friction Tester nearing completion– Applies variable pressure– Measures angular acceleration– Slides sample against interchangeable disk of given material
M
slider to be tested
turntable (carbon disk)
position is movable along arm
M
Mass provides normal force
Encoder on shaft measures acceleration
arm hinge
G
October 2001Pixel Week N. Hartman LBNL 26
ATLAS Pixel Detector
Materials to Be Tested
• Sliding Materials– PEEK
• Glass Filled• Virgin
– Vespel• Moly-Disulfide Filled• Virgin
– PPS• Teflon, Carbon, glass, moly-disulfide filled• Probably not viable
• Substrates– Carbon fiber disks (prospective material and Layup)
• 420 GPa Fiber• 8 Ply Quasi-iso layup• 437 micron thickness
– Non-Woven glass mat on surface (some samples)• Work just starting. No conclusions. May investigate roller
depending upon results
October 2001Pixel Week N. Hartman LBNL 27
ATLAS Pixel Detector
Prototyping Plans
• Short Mandrel– 1 foot long - 1 for glass, 1 for carbon – aluminum or steel– “Dry-run” in autoclave to determine thermal response– Determine final diameters from test layups
• Full Size Mandrel (forward length)– Quotes already received
• Approximately 14,000 to 20,000 USD• 8 Weeks delivery
– Plans to Fabricate forward prototype in glass• All flanges and rail features• Use for production forwards if diameters are correct
• Implications of Glass Forwards/Carbon Barrel on prototyping plans must be assessed
October 2001Pixel Week N. Hartman LBNL 28
ATLAS Pixel Detector
Plans For Near Future
• Import SCT Model into current analyses– Double check SCT loads – ascertain acceptability– Determine pixel stability with reduced stiffnesses
• Begin detailed design of flanges and tubes• Fabricate sample tube sections (1 foot
lengths)• Analyze mounts/end constraints/service
interactions– Eric Anderssen’s presentation