October 2001

1
PST Design UpdatePST CDRoctober 2001
2
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

3
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

4
PST Model
5
FEA Model Important Features
10
45
End Support
30
Hoop Hat Stiffeners (section view)
Bolt flanges
End Supports
Sct mount pads
End Plugs (1 mm equiv. carbon sheet)
6
Support Tube Flange Details
End view of barrel flange (forward flanges have
no Mount bosses and no gas seal features see
below)
Constraint Areas
barrel
forward
7
Flange Bolt Spacing Calculations
Flange 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)
8
Flange Bolt Spacing Calculations (cont.)
Flange load(Forward Load(L/d))
Forward Tube
Flange delta
Barrel tube Assumed rigid
d
Forward And services mass
L
tube Deflection ( 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(1/2p (g/d)1/2)
desire frequency 100 Hz number at left assumes
no ribs -ribs act like bolt constraints
-evenly spaced ribs allow half the number
of bolts Design for 24 bolts in flange
9
Support Flange Bonded Assembly
Old design - now gone for independent thermal
barrier
Flange Face (machined layup)
Stiffeners (layups)
T-nuts (bonded)
Flange base (Layup)
10
PST Boundary Conditions
11
PST Position in Inner Detector
Side C
Side A
ID Flat Rail
View from topall Tube Supports are Horizontal
and Co-planar
TRT
SCT
PIXEL
SUPPORT
TUBE
Support Positions are shown, But constraint
conditions are Not indicated here.
ID Vee Rail
Properties TBD
Constraint TBD
12
Constraint Conditions Fixed/Free ends
Fixed Forward Ends
Free Forward Ends
13
Model Properties
14
PST Analyses
15
Original Model
PEEK Flanges Longitudinal Ribs
16
Carbon Flange Material
Carbon Flanges Longitudinal Ribs
17
Removing Ribs
No Longitudinal Ribs
18
Constrain across SCT
Side C
Barrel
Side a
19
Modal Shapes
Hoops and End Plugs
New Flange Shape
Barrel Constraints
Modes 119 / 119 / 124 / 124
20
Low Stiffness Forwards
Additional Hoops
21
Vibration Results Summary
22
Reaction Loads On SCT
Vertical Bending Both Ends
Horizontal Bending
23
Gravity Sag Calculations
Carbon
Glass
 
DY .57 mm
DY 1.6 mm
24
Comparison to SCT Analyses
Projected uses ratio of SCT to our FEA with
carbon forward tubes

• 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

25
Slider design - materials testing

• Friction Tester nearing completion
• Applies variable pressure
• Measures angular acceleration
• Slides sample against interchangeable disk of
  given material

Mass provides normal force
position is movable along arm
M
arm hinge
turntable (carbon disk)
slider to be tested
Encoder on shaft measures acceleration
M
G
26
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

27
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

28
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 Anderssens presentation