Expertise:

• Linear and nonlinear ultrasonics for characterization of material properties, including temperature dependence (-200 to 350 ºC)
• Design and development of linear, nonlinear, high power and array ultrasonic sensors
• Laser-based linear and nonlinear ultrasonics
• Interaction of ultrasound with light (Bragg diffraction)
• Giant magneto-resistive (GMR) sensor-based eddy current techniques and NDI sensor development

Experience:

Since summer of 2006, Dr. Na has been employed by UDRI to conduct research on the use of linear, non-linear, laser ultrasonics and GMR sensor-based eddy current techniques for characterizing aerospace materials as well as detecting flaws in aerospace structures. Dr. Na conducts his work at the Nondestructive Evaluation Branch in the Air Force Research Laboratory’s Materials and Manufacturing Directorate. Prior to joining UDRI, Dr. Na worked for Wyle Laboratories, Inc. as a technical leader in the company for five  years (2001 – 2006) and conducted research and development for various customers like the US Air Force, Boeing Co. and electric power-generating companies for their NDI system developments.

Dr. Na invented a GMR sensor-based handheld eddy current lap joint scribe line crack detection system for various commercial aircraft fuselages and currently this patent is pending. Dr. Na also conducted research and development at the NASA Langley Research Center for 10 years (1991 – 2001). During this period, he conducted a variety of research projects, including ultrasonic fatigue sensor development for metals. The fatigue sensing technique based on the nonlinear acoustic second harmonic generation method was fully developed for over six years and patented by NASA. This technique is currently being used at the power plants to assess the remaining fatigue lives of steam turbine blades.

Education:

Ph. D., Physics, University of Tennessee, Knoxville, TN 1991
M. S., Physics, University of Tennessee, Knoxville, TN 1986
M. S., Physics, Dong-A University, Korea, 1984
B. S., Physics, Dong-A University, Korea, 1982

Selected Publications:

J. K. Na, “Ultrasonic Inspection of Thin High Performance Composite Structures,” 33rd Annual Review of Progress in Quantitative Nondestructive Evaluation, Vol. 26, 2006 (forthcoming).

J. K. Na, M. A. Franklin, and J. R. Linn, “Detection of Hidden Cracks on Aircraft Lap Joints with GMR based Eddy Current Technology,” 32nd Annual Review of Progress in Quantitative Nondestructive Evaluation, Vol. 25, 2005, pp. 345 – 352.

J. K. Na and M. A. Franklin, “Detection of Subsurface Flaws in Metals with GMR Sensors,” 31st Annual Review of Progress in Quantitative Nondestructive Evaluation, Vol. 24, 2004, pp. 1600 – 1607.

Jeong K. Na, William T. Yost, John, H, Cantrell, and Gregory L. Kessel, “Effects of Surface Roughness and Nonparallelism on the Measurement of the Acoustic Nonlinearity Parameter in Steam Turbine Blades,” 25th Annual Review of Progress in Quantitative Nondestructive Evaluation, Vol. 19, 1999, pp. 1417 – 1424.

Jerome Frouin, Shamachary Sathish, Theodore E. Matikas, and Jeong K. Na, “Ultrasonic Linear and Nonlinear Behavior of Fatigued Ti-6Al-4V”, Journal of Materials Research, Vol. 14, No. 4, pp. 1295-1298.

Jeong K. Na, John, H. Cantrell, and William T. Yost, “Linear and Nonlinear Ultrasonic Properties of Fatigued 410Cb Stainless Steel,” 22nd Annual Review of Progress in Quantitative Nondestructive Evaluation, Vol. 15, 1996, pp. 1347 – 1352.

Jeong K. Na and Mack A. Breazeale, “Ultrasonic Nonlinear Properties of PZT Ceramics,” Journal of the Acoustical Society of America, Vol. 95, No. 6, June 1994, pp. 3213 – 3221.

Van Den Abeele K., Beazeale M. A., Leroy O., and Na J. K., “Strong Interaction of Arbitrary Fields of Sound and Light: Application to Higher-Order Bragg Imaging,” Journal of Applied Physics, Vol. 75, No. 1, January 1994, pp. 84 - 95.

Jeong K. Na and M. A. Breazeale, “Second Harmonic Generation of Ultrasound in Piezoelectric Materials,” Frontiers of Nonlinear Acoustics, M. F. Hamilton and D. T. Blackstock, eds., Elsevier Applied Science, London and New York, 1990, pp. 571 - 576.

Patents:

“GMR Sensor-Based Subsurface Flaw Detection NDI System” (pending)