1. Pressure vs height (solid CPA plane)
Pressure as a function height. Data is “smeared” by pressure variations through the length of the TPC
Linear pressure distribution is assumed for input into a standard beam equation.
1.27
0.84

2. Estimated deflection as a function of height (x) for 6
Estimated deflection as a function of height (x) for 6.35mm thick DUNE (11.8m tall) CPA

3. Estimated deflection as a function of height (x) based on 2 3
Estimated deflection as a function of height (x) based on mm skins with 19mm separation

4. View of CPA model from Bill Sands
1/8” skin
¾” thick bars that space out skins
Interconnecting pieces

5. CPA mechanical requirements (mostly from last meeting)
Flatness less than 10mm (installed flatness plus deflection from convective and pumping flows)
Coating must be protected from scratches once it is applied
CPA must accommodate support movement during roof deflection (Dan Wenman to extract support deflection information from analysis)
Must support the FC and GP above and below.
Structural elements and joints must handle all the combined loads for all load cases.
Must withstand forces during FC installation. ( I think it is best to design connections to avoid moments so only direct loads are applied)
No trapped volumes

6. Addition comments:
If the CPA is assembled on a flat surface and the skins are locked into the structure, the panels should remain pretty flat. Planes must not slip during temperature transients or during cold state.
Fitting a linearly varying load to the CPA plane provides a pretty crude approximation of deflection. FEA would help accuracy.
How accurate is the CFD and what are we comfortable with for safety factor for strength and stiffness?
How comfortable are we with the interconnector strength or do we need to do FEA analysis on the local area around the higher stressed joints.

7. Perforated Cathode Plane

8. DUNE FD
Pressure on CPA with 20% opening
1.27cm holes at 2.54cm center SQ. grid
3mm thick walls separated by 1.27cm.

9. Pressure as a function of TPC length
Pressure as a function of TPC length. Data is “smeared” due to variations in pressure from bottom to top of the plane.

10. 0.196 open fraction in CPA plane
Pressure as a function in height based on CPA fraction open. Data is smeared by pressure variations through the length of the TPC
Maximum pressure profile will have a much different deflection than average pressure profile.
Approximate maximum pressure profile at x= 48m
.72
.36
.19
.32
Approximate average pressure profile

11. Deflection will more likely be something like this, but error bars are large. FEA is really needed.
Deflections estimation for open fraction in CPA plane
Worse case for local APA Column

12. Pressure as a function of TPC length
Pressure as a function of TPC length. Data is “smeared” due to variations in pressure from bottom to top of the plane.