From: Fred Dahlgren
Sent: Thursday, October 04, 2007 12:58 PM
To: Michael R. Kalish
Subject: PF coil Preliminary stress analysis

Attachments: dfout7d-ohmic-1.7T@t=.140-peak-pf4-.txt;
dfout7d-2.0T@t=0.192-peak-pf456-209kA-Plasma.txt;
dfout7d-320kA-ohmic-@t=0.206sec.-46.7kA-PF1.txt;
dfout7d-HiBeta-1.7T@t=.240-peak-pf4-.txt;
dfout7d-ohmic-1.7T@t=.0-peak-pf5&pf6-.txt;
dfout7d-HiBeta-1.7T@t=0-peak-pf5&6-.txt;
dfout7d-2.0T@t=.192-peak-pf4.txt

Mike,

I re-ran the various coil scenarios with the mod coil fields  
included. I have also upped the current in PF1a to 46.7kA per Mike  
Z.s' request. He is hoping to run these at 64kA which may not be  
possible due to stress & thermal limitations.

The worst case average hoop stress (other than PF1a) is 2.385 ksi in  
PF4 for the 320kA ohmic scenario @t=2.06 sec.
(Note there may not be sufficient volt-secs. in the PF1a swing to get  
the full 320kA plasma current).
A comparison of FEA runs with DFORCE7 results for PF1a indicate that  
the average hoop stress calculated by DFORCE7 is generally 60-70% of  
the peak stress calculated by the FEA. I would expect similar peaking  
factors for the other PF coils.

For the other scenarios the hoop & combined stresses are less than 2ksi.
The exception is PF1a which is up to ~11 ksi peak & ~7ksi for the  
average hoop stress in most scenarios.
This is predominantly due to the self fields generated at 46.7kA.

The run summaries are attached below.

-Fred