Agenda 09h00-09h10: Opening & Brief report on TWA16 activities / H. Kitaguchi (NIMS) 09h10-09h25: IEC/TC90 activitie

1. Agenda 09h00-09h10: Opening & Brief report on TWA16 activities / H. Kitaguchi (NIMS) 09h10-09h25: IEC/TC90 activities / Y. Tanaka (ISTEC) 09h25-10h20: Introduction of IEC/TC90 activities on Current Leads / Prof. T. Mito (NIFS) < Break> 10h40-12h00: Topics from participants & discussions Activities in Germany (and Europe) / W. Goldacker (FK) & M. Thoener (EAS) Activities in USA / H. Weijers (NHMFL) Activities in China / G. Zhang (IEE/CAS) < Lunch on each own> 13h00-14h20: Topics from participants & discussions Activities on AC loss of YBCO coated conductors / E. Collings (OSU) Activities on Surface resistance / S.Y. Lee (Konkuk Univ) & S. Kosaka (AIST) Activities on NDE of Ic / H. Yamasaki (AIST) < Break> 14h40-16h00: Topics from participants & discussions Activities on Irreversibility field measurements / T. Matsushita (KIT) Topics on Flux pinning / J. Sosnowski (IEL) Activities on Bending strain effect of HTS tapes / H. Kuroda (NIMS) Activities on Mechanical properties / K. Osamura (RIAS) 16h00: Closing & Adjourn

2. Activities in USA (NHMFL) Presented by H.W. Weijers Measurements performed by Bob Walsh and Dustin McRea Presented at NIMS, Tsukuba Nov 5th 2009

3. Outline • WG-5 • Contribution to KNC Draft IEC 61788-XX • Mechanical properties measurement- Room temperature tensile test of Ag/Bi2223 and Ag/Bi2212 composite superconductors • New activities • WG-12 HTS current leads • 4 kA lead pair test • Summary

4. Recent BSCCO testing • To support completing the draft • Student ran measurements with support • Used both Shepic and Nyilas type extensometer tape wire

5. General setup Load cell

6. Bi-2223 3-ply Brass“raw” data” 1,2 Shepic 3,3 Nyilas

7. Curve fitting of data • Purposes • Provide fit of data • Section Annex 3 • Method to determine initial slope E0 • Section Annex 10 Starting point is existing text for mechanical testing of Nb3Sn

10. Linear and 2nd order poly fit comparison Poly fit has almost always higher R2 value, otherwise equal

11. Curve fitting of initial slope • Proposed: F/So = a+Ei·+b·2 • 2nd order polynomial fit data better than 1st order (linear) fit • Not surprising, but both fit with R2 > 0.99 (old criterion) • Comparable scatter in E0 • Clearly higher R2 values for 2nd order fit • Linear fit trends down with increasing range for s,e, 2nd order fit doesn’t • Range of 0 to 20 MPa min to 100 MPa max • R2should be above 0.999 • “If the above procedure does not converge with increasing range and/or a modified or alternate procedure is used, then the procedure and results (calculated slope and regression coefficient versus stress range) shall be documented in detail (escape clause)

12. Curve fitting over larger rangeR2 values fit to 0.3% Data for increasing strain only (return lines removed)

13. Curve fitting of data 0 to 0.3% • 2nd order polynomial fit to replace power fit • Consistently higher R2 • Trendline power fit in Excel sometimes fails to find proper fit: solver works better • Minimize sum or relative errors • Removed text on increasing lower bound of range above zero (section A-10) • as it does not necessarily improve either fit • Range: 0.3% or 90% of Relasticmax, whichever is lower (was 0.5%) where s-e curve “kinks”

14. Results and proposals • Data with Nyilas and Shepic extensometers very comparable • 2nd order polynomial fit of initial slope • Fits better than linear or a(e-b)n • Not necessarily better predictor of Eo compared to linear • Range defined, and an “out” in case of insufficient convergence • 2nd order polynomial fit of curve to 0.3% • Fits better than a(e-b)n • Clearly a better choice • 0 to 0.5% is too large a range for BSCCO • Test report section 10.2, Optional results • When reporting % elongation to failure, add location of failure (at grips, within extensometer) to report

15. New developments • Bob Walsh is now US Expert on Working Group 5, mechanical properties

16. Robert P. Walsh Magnet Science & Technology, Scientific Staff Educational Background: Rochester Institute of Technology Mechanical Engineering BS (1982) Research Interests: Material properties at low temperature High strength materials Composite materials Mechanical test design Measurement sensor technology, computer data acquisition Professional Experience: 3/93-date Staff Scientist, Magnet Science & Technology, NHMFL, Tallahassee, Florida 5/82-3/93 Mechanical Test Engineer, Materials Reliability Division, NIST, Boulder, Colorado 1/80-5/82 Engineering Co-op Student, Fracture & Deformation Division, NIST Boulder, Colorado 9/78-9/79 Mechanical Technician, SCM Corporation, Cortland, NY Experience: ·Management of a Materials R&D Group (NHMFL) ·Conduct of materials research and development (NHMFL and NIST) ·Engineering materials selection for design (NHMFL and NIST) ··Measurement sensor technology (NHMFL and NIST) ·Technology transfer and data base management (NHMFL and NIST)

17. New developments • Bob Walsh is now US Expert on Working Group 5, mechanical properties • Primarily cryogenic testing • Primary focus is shifting from BSCCO to REBCO coated conductors • 32 T YBCO+LTS user magnet funded

18. Ic-strain apparatusYBCO Ic vs. strain extensometer Copper YBCO tape T = 77 K Voltage taps 40 mm Backing plate is 0.4 x 4 mm2 BeCu

19. Modified stress-strain rig to allow in-situ Icmeasurement of YBCO tape Vince Current contacts integrated with grips Voltage taps Reaction frame Under development now

20. The LN2 System 4 kA HTS current lead testing LN2 Fill Port N2 Supply to VCL Insulating Break LN2 intercept HTS section Terminal LN2 Reservoir Resistive HX > 1 m LN2 Supply to VCL • Instrumentation: • LN2 Level Sensor • 100 Watt Heater to mimic effects of heat load of radiation shield Leads operate in vacuum Cryostat omitted in images

21. 4 kA HTS current lead testing The LHe System Helium boil off is measure of 4 K heat leak (level drop and out-flow) Helium Return LHe Supply Quench Relief and Instrumentation Port Insulating Break 80 K Intercept • Instrumentation: • LHe Level Sensor • Voltage Taps • Pressure Transducer • He flow meter (room temperature) LHe Reservoir Terminals and superconducting jumper Leads operate in vacuum Cryostat omitted in images

22. HTS current lead testing Now we need to add ~0.06 T magnetic field in both radial and axial direction It was challenging to develop a standard that is generally applicable to small (<500 A) and large capacity (multi-kA) leads

23. Summary • Contributed to WG5 KNC draft • 2nd order polynomial fit default for initial slope and curve fit to 0.3% • Other fits allowed if insufficient convergence • Bob Walsh US expert for mechanical testing • Focus: Cryogenic testing & Coated conductors • 4 kA Current lead test (WG-12)