Global Supports Update W.O. Miller October 2001 US ATLAS Pixel Detector Global Supports Status W.O. Miller, R. Smith, W.K. Miller, G. Hayman, R. Baer HYTEC

Global Supports UpdateW.O. MillerOctober 2001

US ATLAS Pixel Detector

Global Supports Status

W.O. Miller, R. Smith, W.K. Miller, G. Hayman, R. Baer

HYTEC

G. Gilchriese, E. Anderssen, N. Hartman, F. Goozen

LBNLOuter Frame and End Cone


US ATLAS Pixel Detector Topics

• Identification of remaining frame issues

– Needs:

• Confirmation and finalization of the global support frame design

– Need information on outer support tube and connection of frame to support tube although largely decoupled by plates at end of frame to which mounts attach

– Present approach

• Preparation of global support details drawings in process

• Updating of the frame dynamic analysis studies will be postponed until all information is firm

• Present results of testing with an end cone designed for the 500mm dia. Frame

The easiest item first

– Frame----where we are now and what we are doing in the near term


US ATLAS Pixel Detector Revised Mass Inputs

Item Frame Structural

Mass-kg Non-Frame Structural Mass-kg

Added-non Structural Mass-kg

Total Mass-kg

Outer frame-3sections 2.55 2.55 End cones-2 0.3 0.3 Disk Support Rings-6 0.47 0.47 Support Ring Mounts-18 0.28 0.28 Sectors-48 2.16 2.16 Disk Services-(30%) 0.78 0.78 Barrel Layer 2 Shell 0.9 0.9 Barrel Layer 1 Shell 0.65 0.65 Staves Layer 1 & 2-(90) 9.90 9.90 Stave Services L1/L2 (30%) 2.85 2.85 B-Layer Shell 0.65 0.65 B-layer Staves-(22) 2.42 2.42 B-Layer Services-(30%) 0.73 0.73 Totals 2.85 0.75 21.04 24.64

Updating of the mass information is in process via Marco

Changes to 0.52

major addition

Barrels(1&2) +disk services, along the outer frame up to PPOCurrent assumption is no weight sharing with outer support tube

10.4kg



Service Ties

Proposed general position of inserts on frame

Approximate location of corner splice

Also here?



Frame Dynamic Solutions

• Comments on new mass inputs

– New input agrees fairly closely to what has been used in our FE analysis: for example the barrel services on the end cone per side was 1.29kg, now is 1.2kg

– Other individual items used at the CDR agree well

– The new item of 5.2kg per side for services (barrel and disks), is shown as “along the outer frame up to PP0”

• Question: what is the mass distribution between frame and support tube?

• At the present we are holding off on any new frame solutions until issues are resolved with the integration of the frame with the support tube and we need this information by about mid-November

– We are, however, proceeding with the preparation of the detail frame drawings and the tooling design

– Our objective is to prepare for the PRR in February 2002



End Cone Developments

(Sponsored by a DOE SBIR)



Development End Cone

• Salient construction points– End Cone for 500mm

frame design

– P30Carbon-carbon facings, ~0.44mm

– XN50/cyanate ester graphite fiber honeycomb, 4mm thick

– YSH50 quasi-isotropic laminate for outer supports and inner tabs

• Static tests– End Cone is mounted on

an optical table, using the 8-mounting tabs

– Force is applied and the deflection monitored with holographic imaging system

White paint on short tab for holographic measurements



End Cone Components

Panel bonding fixture

End cone components

Cone Bi-panel testing

Emphasis on correlations with predictions



• Static Test– Load application on inner mounting tabs– Compliance recorded for mounting tab of

17.6m/N, load applied 2.223cm from end of tab

– Slight error noted in fringe counting over large deflection range

– Approximately 78m’s for 1lbf(4.448N) load

– We note that the fringes are smooth and continuous over the Bi-panel joint indicating proper structural behavior

Bi-Panel Static Test



End Cone TVH Testing

• Static Load Tests– Concentrated force applied to short and

long tabs• For long tab, force was applied at

two radial locations– 1.5875cm, 33.82 m/N – 2.8575cm, two values 16.11

m/N and 11.39 m/N • For short tab force was applied at

one location– 0.635cm—two values

1.733m/N and 1.767 m/N

• Analysis– Can not explain data for the long tab,

force applied at 1.5875cm and 2.8575cm, performed on separate tabs as well

• For a given tab, deflection does not scale as one would expect

• Observations– However, fringe patterns appear to be

smooth and continuous, indicating proper structural behavior

Long Tab

Short Tab



Long Tab Compliance

• Long tab under increased loading

– Blow-up of fringe region

– We see a very localized fringe where tab joins the sandwich

– The localized pattern is suggestive of local bending of the facings

• The FE model may be falling short of correctly depicting the compliance at this interface

• Current thinking is that we need to improve the load transfer in the region of the tab connection to the end cone.

Blue lines are the approximate edge of the sandwich facing



End Cone TVH Results

• Results– Decent comparison

between measured predicted only exists for the inner short tab

– No reasonable explanation exists at this point in time between predicted and measured data for the end cone on the long tabs

– Tests were repeated on the long tab at a location of 2.8575cm, using dial indicator, and similar range in values was noted

– More testing is needed

Distance of from end of tab-

cm

Effective Lever

arm-cm

Measured Compliance

m/N

FEM Compliance

m/N End Cone

Long Tab 2.8575 12.412 11.39/16.11 7.98 1.5875 13.682 33.82 (?) 13.33

Short Tab 0.635 8.842 1.733 1.52



Axial Compliance

• A possible question----how efficient is the conical sandwich structure?

• Consider the deflection of a short tab without sandwich panels on either side.

– For 1kgf, the strip deflects 0.03268cm, at point of load application, a compliance of 33.32m/N (versus 1.733)

– Compliance of a short strip without sandwich panels has 19.23 greater compliance.

• Effect of the panels is quite pronounced, which is desired

Short Tab

Continuous over the joint

Strip only Units cm



• Next, look at the deflection of a long strip without sandwich panels on either side.

– For 1kgf, the strip deflects 0.09831cm, at point of load application, a compliance of 100.3m/N (versus ~16.5)

– Compliance of long tab without sandwich panels has 6.1 greater compliance.

• Again, the panel effect is substantial

Axial Compliance

Full cone

Long tab

Strip only

Units cm



Tangential Compliance

• Objective: figure of merit for R compliance

– Load applied to short tab causing a rotation about a corner

– Deflection amounts to .0396m/N or 0.44 rad/N of rotation at the applied load

• Tangential compliance quoted is for one tab:

– For outer shell the tangential compliance goes down by factor of 8, with a shell connected to all 8-tabs

Applied load

Units cm



Long Tab, connected to three shells

End Cone Tabs

Short Tab, connected to one shell

Stiffness of tabs will be enhanced to some extent by connection to the shell, multiple shells in the case of the long tab



End Cone Summary

• The end cone (500mm dia) tests confirmed our expectations– Axial stiffness of the short tabs is quite high-7*105 N/m (4011lbf/in) per

tab• Axial natural frequency of the barrel region would meet or exceed

the 100Hz goal• However, the analysis of end cone test results is still an active SBIR item

– Our desire is to understand what caused the deviation between predicted and measured results for the long tab

• Simple material tests are planned to ensure the appropriate modulus is being used---although this is not expected to be a significant contributor

• A further evaluation will be made of the connection (FE model) between the sandwich structure and the solid laminate

• A design is under consideration that should simplify the construction of the joint between adjacent flat panels and possibly improve the joint load transfer

• With regards to ATLAS, we just need to verify that our CAD files properly reflect the interface control drawing for Cone A and Cone C.

• We are still on track for the PRR in February 2002

Documents

Global Supports Update W.O. Miller October 2001 US ATLAS Pixel Detector Global Supports Status W.O. Miller, R. Smith, W.K. Miller, G. Hayman, R. Baer HYTEC