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A High-frequency High-temperature Optical Strain/Displacement Gage

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Abstract

This paper describes an optical method for measuring strain or crack-opening displacement at high frequencies (20 kHz) and high temperatures (590°C) on a near-real-time basis. Two small reflective markers are placed on a smooth specimen or across a crack. When illuminated with a laser, interference fringes are generated; their motion can be monitored with photomultiplier tubes. The data acquisition system acquires 200 points per 50 microsecond cycle. These are processed, displayed, and stored at a rate of 25 Hz. Applications are in the general area of very high cycle (109 cycles or more) fatigue. Demonstration tests at 20 kHz at room temperature with a strain range of 0.45 percent and at 590°C with a range of 0.2 percent are presented along with room temperature displacements up to 0.7 µm across the center of a 1.4 mm long crack.

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References

  1. Juvinall RC, Marshek KM (2005) Fundamentals of machine component design. Wiley, pp 293–296

  2. Bathias C, Paris PC (2005) Gigacycle fatigue in mechanical practice, Marcel Dekker.

  3. Nicholas T (2006) High cycle fatigue, Elsevier

  4. Shyam A, Torbet CJ, Jha SK, Larsen JM, Caton MJ, Szczepanski CJ, Pollock TM, Jones JW (2004) Development of ultrasonic fatigue for rapid, high temperature fatigue studies in turbine engine materials. Proceedings International Symposium on Superalloys, SUPERALLOYS 2004, pp 259-268.

  5. Sharpe WN Jr (1989) An interferometric Strain/Displacement measurement system. NASA Technical Memorandum 101638 .

  6. Sharpe WN Jr (2003) Tensile testing at the micrometer scale: opportunities in experimental mechanics. Experimental Mechanics 43:228–237

    Google Scholar 

  7. Sharpe WN, Jr (2007) A 20 Kilohertz optical strain gage. Proceedings Fourth International Conference on Very High Cycle Fatigue

  8. Sharpe WN Jr (2007) A 20 kilohertz, high temperature, optical strain gage. Proceedings 2007 SEM Annual Conference and Exposition on Experimental and Applied Mechanics

  9. Sharpe WN Jr (2007) A 20 kilohertz optical strain gage. Proceedings International Conference on Experimental Mechanics-13

  10. Sharpe WN Jr (2007) High-frequency high-temperature strain/displacement gage. DARPA Contract No. FA8650-04-5212 http://www.me.jhu.edu/sharpe/DARPAFinalReport23.pdf

  11. Jenkins FA, White HE (1950) Fundamentals of optics. McGraw Hill, New York

    Google Scholar 

  12. Sharpe WN Jr, Waclawiw Z, Douglas AS (1988) Dynamic measurement of CTOD. Proceedings ASTM STP 969, Fracture Mechanics: Nineteenth Symposium, American Society for Testing and Materials, pp 466-481

  13. Sukere AA, Sharpe WN Jr (1983) Transient response of a central crack to a tensile pulse. Experimental Mechanics 23:89–98

    Article  Google Scholar 

  14. Sharpe WN Jr, Shapiro JM (1990) Dynamic K measurements in three-point-bend specimens. Journal of Testing & Evaluation 18:38–44

    Article  Google Scholar 

  15. Tregoning RL, Shapiro JM, Sharpe WN, Jr. (1994) Dynamic Crack-Tip Opening Displacement (CTOD) measurements with application to fracture toughness testing. Proceedings ASTM STP 1130, Rapid Load Fracture Testing, pp 118-133

  16. Sharpe WN Jr (1970) Dynamic strain measurement with the interferometric strain gage. Experimental Mechanics 10:89–92

    Article  Google Scholar 

  17. Li K, Sharpe WN Jr (1996) Viscoplastic behavior of a notch root at 650°C: ISDG measurement and finite element modeling. Journal of Engineering Materials and Technology 118:88–93

    Article  Google Scholar 

  18. Bagdahn J, Sharpe WN Jr (2003) Fatigue of polycrystalline silicon under long-term cyclic loading. Sensors and Actuators A (Physical) A103:9–15

    Article  Google Scholar 

  19. Kim, Chung-Youb. Division of Mechanical and Automotive Engineering, Chonnam National University, San 96-1, Dunduck-dong, Yosu, Chonnam, 550-749, Korea. Email kimcy@chonnam.ac.kr.

  20. Sharpe WN Jr, Turner KT (1999) Fatigue testing of materials used in microelectromechanical systems. Proceedings FATIGUE ’99 – Proceedings of the Seventh International Fatigue Congress, Beijing, pp 1837-1844.

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Acknowledgements

Professor Wayne Jones of the University of Michigan’s Department of Material Science stimulated this work. Graduate student Chris Szczepanski and Research Engineer Chris Torbet of his group assisted in the installation and testing in his laboratory. Dr. Leo Christodoulo of DARPA arranged the financial support to develop the prototype presented here through Contract No. FA8650-04-5212 in 2005. The author is very grateful to them all for the opportunity to work on a very interesting and rewarding experimental solid mechanics system.

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Authors and Affiliations

  1. Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA

    W. N. Sharpe Jr. (SEM member)

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  1. W. N. Sharpe Jr.
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Correspondence to W. N. Sharpe Jr..

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Sharpe, W.N. A High-frequency High-temperature Optical Strain/Displacement Gage. Exp Mech 50, 227–237 (2010). https://doi.org/10.1007/s11340-009-9278-x

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  • DOI: https://doi.org/10.1007/s11340-009-9278-x

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