Coupled Layer Prototype Update

1. Coupled Layer Prototype Update E Anderssen, M Cepeda, M Gilchriese, N Hartman, T Johnson, J Silber, LBNL W Miller Allcomp Inc ATLAS Upgrade Week, November 2010 CERN

2. Thermo-Mechanical Prototype Tested • First functional prototype available since April • Recall that the goal is to use short prototype to verify FE Model parameters, then scale model in length • Used ‘K9’ Allcomp foam (130ppi 40W/mK)—then just available (April) • Layout design is diverging from this cross-section, but only in details, not scale

3. Laminate Definition (reminder) • Aim of laminates are to be balanced after bonding together as ‘core’ • Most important for “Web” Section—if it twists thermally, more difficult to make straight structures • Central Part of web has opposite angles ‘Top’ versus ‘Bottom’ • Requirement sets integral number of plies and sets of orientations • Room to Change Fibers/Angles to tune performance Upside Down “Web” Side B Side A

4. Deflection Test (done in April) • Measured Bottom to extract beam deflection • Loads not typical of Final application • Loads up to 4.6kg applied to Beam (~55g) • Required to get measurable deflections • Used results of this test to tune model material properties • Note significant twist—moved on to verify Plotted Deflection Four-Point Bend

5. Torsional Stiffness correlation • Load is applied eccentrically in four-point bend test (same load as before) • Deflections measured by dial test indicators • Captures more complex behavior than simply measuring deflection at one point • FEM seems to correlate well with the data +ecc LOAD

6. Thermal Performance Outer Face (April) • Increased Edge Thickness of Top Foam to improve thermal performance; plus larger tube • Model calculated temp to silicon w/SE4445 but did not include conductivity from the Si • Better width range 3.2C versus 5C • Power density is ~10% low (power supply limit) • Scaling for power, results appear within 10% of expected for average DT and Max to Coolant • Mid-line bond seems to be unimportant… Avg DT 8C 5C 9.4C Max DT from Coolant 0.458W/cm2 Coolant Temp 19.4

7. Thermal Performance Inner Face (April) • Smaller width and less overall power allow the tube to be smaller; doesn’t require foam to wrap around backside for adequate performance • Power density is correct at 0.5W/cm2 • Avg DT calculated and measured also appear to be within 10% • Range of 2.1C versus 3C comparable to outer from Si averaging 3C 7.5C Avg DT 6C Max DT from Coolant 0.503W/cm2 Coolant Temp 19.4

8. Foam Cross Sections versus Material (April) • Test Results indicate that current foam sections are adequate • Foam for both is K9 130ppi ~40W/mK • Hard to reduce cross-section of Inner Foam—Geometry Driven • Could go back to K7 100ppi foam ~20W/mK to reduce material, but increase DT • Something in-between might be desirable, but wait for X0 calc to guide decision • Outer Foam seems to require K9, and increased thickness at edges • Could investigate thinning section at edges, currently 2.4mm (reduce overall thickness for prototype) • ‘Final Design’ would be able to change angle of backside independently… ‘peaks’ removed For Fabrication

9. Structural Thermal Modeling 32655 Nodes 16050 Elements Sweep resolution is 50 divisions along the 1m length • Previous models (april) done in combination of Cosmos (Thermal), and ANSYS v11 (Structural) • New combined model in ANSYS V12.1 • Shell99 (and believe 199) no longer actively supported in v12 • Recently Acquired ANSYS Composite Pre/Post package which addresses this, but seeking guidance from ANSYS Corp.

10. Solid Model input to FEM 4cm x 4cm heater SE4445 bond Outer facesheet Carbon foam Cable Outer coolant tube Flange Web Close-out Inner coolant tube Cable Inner facesheet SE4445 bond 2cm x 4cm heater

11. Thermal Distortion Modeled/Tested 501 IR temp data  B.C. for FEA Solve two thermal-stress analyses at the two setpoints and then compare to TVH data TV holography data  Differential deflection between 2 setpoints (2 different power inputs to silicon)

12. Comparison of TVH to FEA 2.0m ‘zero’ is arbitrary In TVH Data… • 3D plot is inverted (artifact of ‘sense’ of TVH sensitive vector) • Character of deflection FEA vs TVH is similar—scaling is a bit off • FEA ~1.6m, TVH ~2m range, but noisy 2.1m

13. Comments • TVH measurement over ~1.8C; Temp measurement accuracy in the +/- 0.1-0.2C range • Imaging long thin objects difficult—limited pixel count across width, limits fringe count • Can change field of view to double deflection range (up to 4m), but only for short stave sample (will do) • As with thermal and deflection measurements, aim is to establish parameters for FEM, then use these to extend to model of full length stave • Current correlation is good, but would like to improve fidelity of TVH measurement It should be pointed out that these measurements are not indicative of final performance

14. Good Correlation • Good agreement between physical test and FEA under: • 4 point bend loading, with complex twists due to eccentricity • Thermal deflection • All ply thicknesses and orthotropic properties were determined directly by scripted calculations independent of ANSYS • Micromechanics for orthotropic stiffness and thermal properties • Resin bleed-out for cure ply thickness • Did not use Shell99/199 for these results • This gives confidence that we are accurately predicting our properties from “first principles” • Verifies that our manufacturing process conforms to our design • Have extended these to a 1m model, results follow

15. Simple Support Mode 1 • Mode is in the ‘less stiff’ direction of the I-Beam • End Fixity effect not dramatic for this mode • This is the ‘horizontal’ gravity deflection • Not easy to stiffen in this direction due to layout…

16. Simple Support Mode 2 • Deflection mostly ‘Vertical’ (in W direction) • Significant ‘rotation’ about simple support in this mode • This mode responds well to end fixity • Varies from 126Hz (simple) to 176Hz (fixed)

17. Simple Support Mode 3 • Mode shape as expected for HOM • Mostly lateral HOM of mode 1 shape • Insensitive to end fixity

18. Summary 1.2m Stave Performance • End fixity of model varied between simple and cantilever to bound problem • F1 is mostly ‘Horizontal’ so insensitive to end fixity • F2 is sufficiently high not to care ? • End fixity seems to be less important that lateral stiffness

19. Conclusion • Short I-Beam prototype testing correlates well with FEM • Ability to calculate FEA inputs for composite materials from FAW and RC demonstrated • Provides convincing evidence that scaling to Longer Length will be accurate, also studying effects from changes due to layout • Sectional inertia will likely decrease in the important dimension when realistic layouts are applied • Current Prototype(s) use M46J fiber which is~400GPa; 800GPa fibers are readily available • Next steps to complete a 1m prototype, and develop a more realistic service cross-section (layout)

20. Backup Slides

22. Clamped support, mode 1

23. Clamped support, mode 2

24. Clamped support, mode 3

25. Mesh, all bodies 32655 Nodes 16050 Elements Sweep resolution is 50 divisions along the 1m length

26. Mesh, composite shells only

27. FEA model showing shell bodies and solid bodies (dark background so that the faint shell edges will show up)

28. Solid model

29. Solid model