Flywheel Safety - Richard thompson - Jan 2011


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Flywheel Safety - Richard thompson - Jan 2011

  1. 1. <ul><li>Center for Electromechics </li></ul><ul><li>The University of Texas at Austin </li></ul><ul><li>Flywheel Safety </li></ul><ul><li>Richard Thompson </li></ul><ul><li>January 6, 2011 </li></ul>
  2. 2. Presentation <ul><li>Our approach to flywheel safe and reliable operation </li></ul><ul><li>DARPA Flywheel Safety Program </li></ul><ul><li>Flywheel topologies </li></ul><ul><li>Flywheel rotor design approach </li></ul><ul><li>CEMWIND for advanced prototypes </li></ul><ul><li>ANSI/AIAA Flywheel Standard </li></ul><ul><li>Rotor testing </li></ul><ul><ul><li>Provides data for model correlation </li></ul></ul><ul><ul><li>Shows understanding of design and fabrication principles </li></ul></ul>
  3. 4. DEFENSE IN DEPTH PHILOSOPHY – Our approach to safe and reliable operation
  4. 5. DARPA Program Team <ul><li>Center for Transportation and the Environment, Program administrator </li></ul><ul><li>University of Texas –Center for Electromechanics, Co-program technical manager </li></ul><ul><li>Test Devices, Inc., Co-program technical manager </li></ul><ul><li>AFS Trinity Power Corp., Commercial flywheel developer </li></ul><ul><li>US Flywheel System, Commercial flywheel developer </li></ul><ul><li>Beacon Power Corp., Commercial flywheel developer </li></ul><ul><li>Lawrence Livermore National Laboratory </li></ul><ul><li>Oak Ridge National Laboratory </li></ul><ul><li>Argonne National Laboratory </li></ul>
  5. 6. Program Highlights <ul><li>Conducted more than 60 flywheel tests, including </li></ul><ul><ul><li>Flywheel only tests to identify failure modes and structural margins </li></ul></ul><ul><ul><li>Better understanding of safe flywheel designs </li></ul></ul><ul><ul><li>Flywheel burst tests to successfully proof test candidate containment designs </li></ul></ul><ul><li>Demonstrated life of more than 110,000 cycles with a 50% DOD </li></ul>
  6. 7. Flywheel Topologies
  7. 8. Range of CEM Flywheel Systems Designs Lab Bearing Amps Flywheel Transformer Rectifier Assembly Lab Safety Disconnect Converter Transit Bus Flywheel 150 kW (peak), 100 kW (cont.), 2 kW-h Advanced Locomotive Propulsion System Flywheel 3 MW (peak), 2 MW (cont.), 100 kW-h Combat Hybrid Power Systems (CHPS) Flywheel 5 MW (peak), 350 kW (cont.), 7 kW-h Space Station Flywheel (FESS) 5.0 kW (peak), 3.66 kW (cont.), 3.66 kW-h
  8. 9. Flywheel Rotor Design Approach <ul><li>Coupon-level testing – to determine material allowables </li></ul><ul><li>Component-level testing – first level of test verification </li></ul><ul><li>Prototype build and commissioning </li></ul>
  9. 10. Typical Types of Coupon-Level Tests <ul><li>Baseline material tests </li></ul><ul><li>Tensile </li></ul><ul><li>Compression </li></ul><ul><li>Shear </li></ul><ul><li>Thermal </li></ul><ul><li>Residual strength material tests </li></ul><ul><li>Hoop tensile </li></ul><ul><ul><li>Thermo-mechanical ultimate </li></ul></ul><ul><ul><li>Fatigue (accelerated) </li></ul></ul><ul><ul><li>Effects of vacuum/outgassing </li></ul></ul><ul><ul><li>Effects of critical flaws </li></ul></ul><ul><li>Creep – preload loss </li></ul><ul><li>Stress rupture </li></ul><ul><li>Objective: Obtain material property allowables specific to program requirements </li></ul><ul><li>Lowest level of definition is at the fiber ply level (unidirectional lamina tow) </li></ul><ul><li>Transversely isotropic materials have five independent modulus (~stiffness) components </li></ul><ul><ul><li> 11 ,  22 ,  12 ,  31 and  23 </li></ul></ul><ul><ul><li>Measured from induced strain response and calculated stresses </li></ul></ul>Tests measure shear strength within the plane of lamination (S 21 ).
  10. 11. Hydroburst Test Method (Circumferential Properties) <ul><li>To Characterize: </li></ul><ul><li>Tensile strength, modulus </li></ul><ul><li>Flaw sensitivity </li></ul><ul><li>Fatigue properties </li></ul><ul><ul><li>400,000 cycles </li></ul></ul><ul><ul><li>200 o F </li></ul></ul><ul><li>QA: assess material lot variability </li></ul><ul><li>Pressurized fluid enters through radial feed hole </li></ul><ul><li>Expands Teflon seal </li></ul><ul><li>Radial pressure induces hoop strain in composite ring </li></ul>
  11. 12. Coupon-Level Characterization Single cycle hydroburst fixture Fatigue cycle hydroburst fixture Hydroburst specimen Fixtures can be configured for elevated temperature testing
  12. 13. Hydroburst method has been well reviewed <ul><li>Hydroburst method valuable for </li></ul><ul><ul><li>CEM has seen good agreement between hydroburst data and prediction of flywheel rotor test results </li></ul></ul><ul><ul><li>Screening tool for flaw sensitivity and material QA </li></ul></ul><ul><li>ASTM Composite Materials: Testing and Design, 14 th Volume, STP 1436, “Hydroburst Test Methodology for Evaluation of Composite Structures” </li></ul>
  13. 14. Typical Stress Allowables (Past Composite Program)
  14. 15. Component-Level Characterization Arbor spin test Arbor static deflection test Rotordynamics Testing: Modal frequency test
  15. 16. Creep/Stress Relaxation Tests <ul><li>Creep/stress relaxation tests </li></ul><ul><ul><li>Monitor steel rings’ dimensional change vs time and temperature </li></ul></ul><ul><ul><li>Infer change in preload,  r </li></ul></ul><ul><ul><li>Test duration: 2 years </li></ul></ul><ul><ul><li>Projected  r change over 10 years at 200 o F is 7% </li></ul></ul>
  16. 17. Final Prototype Build and Commissioning Tests Final 2 Arbors In process winding of an arbor pair BUILD Rotor shafts with structural and cooling arbor assemblies installed FINAL PRODUCT In process winding of a B2 outer banding Twin rotors shown in incomplete assembly state ( some outer banding assemblies remain)
  17. 18. <ul><li>CEMWIND </li></ul><ul><li>Analysis Code for Complex Rotor Structures </li></ul>
  18. 19. Arbor Design Control <ul><li>CEMWIND: Filament winding design and fabrication code </li></ul><ul><li>Designer inputs </li></ul><ul><ul><li>r, z,  </li></ul></ul><ul><li>Fabrication checks </li></ul><ul><ul><li>Friction </li></ul></ul><ul><ul><li>Bridging </li></ul></ul><ul><li>Code attempts to optimize for geodesic wind </li></ul><ul><ul><li>No tow slip </li></ul></ul>
  19. 20. CEMWIND Outputs CEMWIND FE Mesh & Material Property Files Arbor Ply Thickness Build Profile Fiber motion files for input into CEM’s filament winding machine
  20. 21. CEMWIND Output Showing Arbor Shear Stress Profile Outputs ply-level stress and strain results. Direct comparison with fiber tow-level material allowables Arbor Stresses at 50 Krpm: Shear Stress Profile
  21. 22. ANSI/AIAA Standard for Flywheels Government Sponsors: Kerry L. McLallin, NASA Glenn Research Center Dr. Jerry Fausz, AFRL - Phillips Lab <ul><li>Objective </li></ul><ul><ul><li>Develop an industry consensus standard for the certification of flywheel rotors for aerospace applications </li></ul></ul><ul><ul><li>Assure that flywheel rotors developed for government missions can meet safety and life requirements </li></ul></ul><ul><ul><ul><li>Center for Electromechanics </li></ul></ul></ul><ul><ul><ul><li>Penn State University </li></ul></ul></ul><ul><ul><ul><li>Lockheed Martin </li></ul></ul></ul><ul><ul><ul><li>Honeywell </li></ul></ul></ul><ul><ul><ul><li>Flywheel Energy Systems/Canada </li></ul></ul></ul><ul><ul><ul><li>National Research Council/Canada </li></ul></ul></ul><ul><ul><ul><li>Toray Composite America </li></ul></ul></ul><ul><ul><ul><li>Beacon Power </li></ul></ul></ul><ul><ul><ul><li>Boeing Seattle </li></ul></ul></ul><ul><ul><ul><li>Barbour Stockwell </li></ul></ul></ul><ul><ul><ul><li>Oak Ridge National Lab </li></ul></ul></ul><ul><ul><ul><li>Lincoln Composites </li></ul></ul></ul><ul><ul><ul><li>Test Devices, Inc. </li></ul></ul></ul><ul><ul><ul><li>AFS Trinity </li></ul></ul></ul><ul><ul><li>ANSI/AIAA Standard was accepted in 2004 </li></ul></ul><ul><ul><li>S-096-2004, Space Systems – Flywheel Rotor Assemblies </li></ul></ul><ul><ul><li>Being used for non-military flywheel applications </li></ul></ul><ul><ul><ul><li>Performance race vehicles: Formula One </li></ul></ul></ul><ul><ul><ul><li>Others </li></ul></ul></ul>
  22. 23. Examples of Past Arbor Spin Tests <ul><li>Pulsed Generator Program </li></ul><ul><li>Successful completion of 1000 fatigue cycles between 7500 rpm to 15,000 rpm. </li></ul><ul><li>Well behaved, stable operation </li></ul><ul><li>Matched analysis predictions </li></ul><ul><li>NASA Arbor Development Program </li></ul><ul><li>Ten spin tests completed </li></ul><ul><li>Focus was composite arbor with high-strength rim </li></ul><ul><li>Demonstrated service speed of 50,000 rpm (1100 m/s) </li></ul><ul><li>Well behaved, stable operation </li></ul><ul><li>Matched analysis predictions </li></ul><ul><li>Overspeed test to verify margins </li></ul><ul><ul><li>Demonstrated FoS of 1.5 </li></ul></ul>Excerpt from NASA Glenn’s 2003 NASA R&T publication: “ The rotor was tested on 9/3/03 and successfully reached 1337 m/s (2990 mph) tip speed. This represents the highest known attained speed in any useable flywheel configuration .”
  23. 24. Rotor Fatigue Tests <ul><li>DARPA Flywheel Program, 2002 </li></ul><ul><li>Completed over 112,000 fatigue cycles </li></ul><ul><li>Flywheel speed excursions from 27,000 rpm to 36,000 rpm, with a peak tip speed of 825 meters/second, at about 140 o F </li></ul><ul><li>Flywheel test to overspeed - verified no loss in residual stiffness </li></ul><ul><li>Goal of test was to better understand flywheels for space applications – Low Earth Orbit </li></ul><ul><li>Significantly increased fatigue test cycles achieved for a full-scale composite flywheel operating in realistic simulated service conditions </li></ul><ul><li>Low earth orbit missions for a 15 year service life require about 90,000 cycles </li></ul><ul><li>Test exceeded this cycle requirement </li></ul><ul><li>At the time, at 50% DOD, much greater number of cycles than possible with chemical batteries </li></ul>
  24. 25. Loss of Vacuum Test <ul><li>Near instantaneous loss of vacuum from 900 m/s tip speed </li></ul><ul><li>No structural damage observed based upon results from follow-up spin tests </li></ul><ul><li>R.C. Thompson, J. Kramer, and R.J. Hayes, “Response of an urban bus flywheel battery to a rapid loss-of-vacuum event,” SAMPE (Society for the Advancement of Material and Process Engineering) Journal of Advanced Materials, vol. 37, no. 3, July 2005, pp. 42-50 </li></ul>Comparison of measured and calculated flywheel angular velocity during a loss-of-vacuum event Comparison of calculated flywheel surface temperature with measured temperature shifted to match room temperature prior to the transient
  25. 26. Methodologies for Composite Flywheel Certification <ul><li>G.Y. Baaklini, K.E. Konno, R.E. Martin, and R.C. Thompson, “NDE methodologies for composite flywheels certification,” 2000 Power Systems Conference, San Diego, California, U.S.A., October 31-November 2, 2000, SAE Document Number: 2000-01-3655. </li></ul><ul><li>Collaboration with NASA Glenn </li></ul><ul><li>Rotors were fabricated with flaws </li></ul><ul><ul><li>NDE methods were applied to evaluate their effectiveness for flaw detection </li></ul></ul><ul><ul><li>CT, radiography, ultrasonics </li></ul></ul><ul><li>Also,intentionally seeded delamination, tow break, and foreign materials (bagging materials) into hydroburst rings </li></ul><ul><ul><li>Determine effects of induced flaws on hydroburst material allowables (damage tolerance) </li></ul></ul>