# Presentation: 629442

## Preliminary Analysis 

- Preliminary Analysis
- of
- TF Joint Behavior*
- C Neumeyer
- NSTX Team Meeting
- 2/12/4
**Summary from 1/29/4 Presentation*

## Outline

-  Overall Questions to be Addressed
-  Description of Measurements
-  Measurements from ISTP Shots
-  Measurements vs. Analysis
-  Measurement Trends
-  Issues & Follow-on Work

## Questions To Be Addressed

- Does measured behavior agree with analytic model?
- How much difference between measurements and predictions?
- Does model need to be changed?
- Does operating envelope need to be reconsidered?
- Do all joints of the same type behave the same way?
- What variation exists joint-to-joint?
- Are any joints significantly different than others?
- 3) 	Is behavior changing as more load cycles are applied?

## Resistance Measurements

- R = Rbulk + Rcontact

-  Outer:
- - Predicted 75nOhm
- - Measured 40nOhm avg.
-  Inner:
- - Predicted 95nOhm
- - Measured 75nOhm avg.

## Fiber Optic Temperature, Strain, 

- Displacment Measurements

-  Four Flags (inner, outer/top, bottom)
- 4 flags x 3 strain/flag = 12 strain
- 4 flags x 1 temp/flag = 4 temp

- FISO Technologies, Inc.

*Total 21 transducers*

*8 conditioner channels*

-  Hub and Flag twist angle (inner, outer/top, bottom)
- 4 displacement

-  Spline (top only)
- 1 displacement

## ISTP-001 Shot & Signal List

- 14 shots 1/16-1/20

## TF-only Shots (110795,6,7,8)

- TF-only Shots (110795,6,7,8)

* **53.4kA shot non-linearity*
* **LH/RH Strain gauges disagree at 46.2 & 53.4kA*

- Vprobe x100 (V)

- Itf
- (A)

- Tflag (degC)

- ∆ Sflag (μS)

- ∆ Sflag (μS)

- ∆LSpline (mils)

*Non-linear behavior*

## Combined Field Shots (110799,803)

- Vprobe x100 (V)

- 795
- 799
- 798
- 803

- 795
- 799
- 798
- 803

- 795
- 799
- 798
- 803

- 799
- 803

- Tflag (degC)

- ∆ Sflag (μS)

- ∆LSpline (mils)

- ∆ Sflag (μS)

- Ioh
- (A)

- Ioh
- (A)

*OOP Effect*

*Temperatures*
*Not effected much*

*OOP Effect LH & RH Side*

*Vibration?*

## Analysis vs. Measurements - Resistance

- 20_20 = Outer/Top

- TF-Only Measured

- Combined TF-PF (max time point)

- Brooks Analysis
- (two sides of joint,
- Combined TF-PF)

- OOP Effect

* **IP may be on*
*Track, but OOP*
*appears larger*
* **Some joints show much *
*larger IP-OOP variation*

## Analysis vs. Measurements - Temperature

*Discrepancies may arise from... *
*probe response*
*probe averaging over length*
*non-linear behavior inc’l contact thermal conductivity*

## Analysis vs. Measurements - Strain (TF-Only)

*Tracks pretty well *
*until 53.4 kA case*

## Analysis vs. Measurements - Strain (con’t)

* **Analysis predicts more OOP strain variation than measured*
* **Analysis predicts more EOFT strain than measured*

## Analysis vs. Measurements - Strain (con’t)

* **Analysis overestimates up to 46.1kA, underestimates at 53.4kA*

## Trending of Resistance Measurements

- (H. Schneider/R.Marsala/D. Mastrovito)

- SOP

- SOFT

- EOFT

- EOFT

- R = Vavg/Iavg over interval

## 200A Trend from 1/12 to 2/6/04 

*Data includes 2 measurements at 2 gains per test*

## 5kA SOP Trend

- Last 200 shot #’s

*Some early data did not have clean TF-only pedestal*

## SOFT Trend

- Last 200 shot #’s

*19_19*

*TF Current*

## Summary

- 	@ full I2T we have... 4.5e9A^2-sec*200e-9ohm ~1000W-sec
- 2) Difficult nano-Ohm  resistance measurements have been successful
- ~ 200x resolution of prior method
- 3) Refinements of FEA models are needed to benchmark against measurements
- 4) Joint-joint variations exist, but min/max depends on case (200A/SOP/SOFT/EOFT)

## Need to Develop Spin-off FEA Models to Capture Detailed Behavior at Joint Where Probes Are Located

## Issues & Follow-On Work

- 2) Measure joint resistance vs. pressure of prototype flag
- 3) Using 1) and 2), benchmark model vs. measurements
- 4) Repeat prototype test
- - reconsider method of force application to better simulate real condition
- - vary in-plane and out-of-plane loads and measure resistance
- run high current test?
- 5) Based on all the above, and consideration of measurement variability, develop definition of allowable for TF operation (6kG)

- (R. Woolley, I. Zatz)