ASTM International, ASTM E1316, Standard Terminology for Nondestructive Examinations, West Conshohocken, PA, ASTM International, 2006. Bellenger, F., H. Mazille and H. Idrissi, “Use of Acoustic Emission Technique for the Early Detection of Aluminum Alloys Exfoliation Corrosion,” NDT&E International, Vol. 35, 2002, pp. 385-392. Dai, Y. and S.A. McInerny, “Basic Vibration Signal Processing for Bearing Fault Detection,” IEEE Transactions on Education, Vol. 46, No. 1, 2003, pp. 149-156. Davidson, J.A., “A Review of the Fatigue Properties of Spot-Welded Sheet Steels,” SAE Technical Paper No. 830033, Society of Automotive Engineers, Warrendale, PA, 1983. Dimarogonas, A.D., “Vibration of Cracked Structures: A State of the Art Review,” Engineering Fracture Mechanics, Vol. 55, No. 5, 1996, pp. 831–857. Doebling, S.W., C.R. Farrar and M.B. Prime, “A Summery Review of Vibration- based Damage Identification Methods,” Shock and Vibration Digest, Vol. 30, No. 2, 1998, pp. 91-105. Emamian, V., “Acoustic Emission Classification for Failure Prediction Due to Mechanical Fatigue,” Proceedings of SPIE, Vol. 3986, 2000. Friswell, M.I., J. Penny and D. Wilson, “Using Vibration Data and Statistical Measures to Locate Damage in Structures,” Modal Analysis, Vol. 9, 1994, pp. 239-254. Grondel, S., C. Delebarre, J. Assaad, J. Dupuis and L. Reithler, “Fatigue Crack Monitoring of Riveted Aluminium Strap Joints by Lamb Wave Analysis and Acoustic Emission Measurement Techniques,” NDT & E International, Vol. 35, No. 3, 2002, pp. 137-146. Hanchi, J. and B.E. Klamecki, “Acoustic Emission Monitoring of the Wear Process,” Wear, Vol. 145, 1991, pp. 1-27. Ismail, F., A. Ibrahim and H.R. Martin, “Identification of Fatigue Cracks from Vibration Testing,” Journal of Sound and Vibration, Vol. 140, 1990, pp. 305-317. Kim, Y.P., M. Freqonese, H. Mazille, D. Feron and G. Santarini, “Ability of Acoustic Emission Technique for Detection and Monitoring of Crevice Corrosion on 304L Austenitic Stainless Steel,” NDT&E International, Vol. 36, 2003, pp. 553-562. Krawczuk, M. and W. Ostachowicz, “Damage Indicators for Diagnostic of Fatigue Cracks in Structures by Vibration Measurements — A Survey,” Journal of Theoretical and Applied Mechanics, Vol. 34(2), 1996, pp. 307- 326. Ostachowicz, M.W. and M. Krawczuk, “Analysis of the Effect of Cracks on the Natural Frequencies of a Cantilever Beam,” Journal of Sound and Vibration, Vol. 150, 1991, pp. 191-201. Pal, K. and D.L. Cronin, “Static and Dynamic Characteristics of Spot Welded Sheet Metal Beams,” Journal of Engineering for Industry, Vol. 117, 1995, pp. 316-322. Pandey, A.K. and M. Biswas, “Damage Detection in Structures Using Changes in Flexibility,” Journal of Sound and Vibration, Vol. 169, No. 1, 1994, pp. 3-17. Physical Acoustics Corporation sensor calibration certificates. Roques, A., M. Browne, J. Thompson, C. Rowland and A. Taylor, “Investigation of Fatigue Crack Growth in Acrylic Bone Cement Using the Acoustic Emission Technique,” Biomaterials, Vol. 25, No. 5, 2004, pp. 769- 778. Salawu, O.S., “Detection of Structural Damage through Changes in Frequencies: A Review,” Engineering Structures, Vol. 19, No. 9, 1997, pp. 718-723. Satonaka, S. and K. Matsyama, “Review on Inspection Techniques for Spot welds,” Welding Research Abroad, Vol. 47, No. 3, 2001, pp. 4-10. Shang, D., M.E. Barkey, Y. Wang and T.C. Lim, “Effect of Fatigue Damage on Dynamic Response Frequency of Spot-welded Joints,” International Journal of Fatigue, Vol. 25, No. 4, 2003, pp. 311-316. Shen, M.H.H. and C. Pierre, “Natural Modes of Bernoulli-Euler Beam with Symmetric Cracks,” Journal of Sound and Vibration, Vol. 138, 1990, pp. 115-134. Shen, M.H.H. and J.E. Taylor, “An Identification Problem for Vibrating Cracked Beams,” Journal of Sound and Vibration, Vol. 150, 1991, pp. 457- 484. Sheppard, S.D. and M. Strange, “Fatigue Life Estimation in Resistance Spot Welds: Initiation and Early Growth Phase,” Fatigue & Fracture of Engineering Materials & Structures, Vol. 15, No. 6, 1992, pp. 531-549. Shiwa, M., A. Yamaguchi, M. Sato, S. Murao and M. Nagai, “Acoustic Emission Waveform Analysis from Weld Defects in Steel Ring Samples,” NDE Performance Demonstration, Planning, and Research, ASME Pressure Vessels and Piping Conference, PVP v352/NDE, Vol. 16, July 27- 31, 1997, pp. 65-70. Singh, A., D.R. Houser and S. Vijayakar, “Detecting Gear Tooth Breakage Using Acoustic Emission: A Feasibility and Sensor Placement Study,” Journal of Mechanical Design, Vol. 121, 1999, pp. 587-593. Sun, Q., S.A. McInerny and W. Hardman, “Detection of a Helicopter Input Pinion Bearing Fault Using Interstitial Envelope Analysis,” International Journal of Vibration and Acoustics, Vol. 11, No. 3, 2006. Tandon N. and A. Choudhury, “A Review of Vibration and Acoustic Emission Measurement Methods for the Detection of Defects in Rolling Element Bearings,” Tribology International, Vol. 32, 1999, pp. 469-480. Thrane, N., “The Hilbert Transform,” Technical Review No. 3 – 1984, Bruel & Kjaer Instruments, Marlborough, MA, 1984. Tsyfansky, S.L. and V.I. Beresnevich, “Detection of Fatigue Cracks in Flexible Geometrically Non-linear Bars by Vibration Monitoring,” Journal of Sound and Vibration, Vol. 213, No. 1, 1998, pp. 159-168. Wang, Y. and T.C. Lim, “An Experimental and Computational Study of the Dynamic Characteristics of Spot-welded Sheet Metal Structures,” Spot Welding and Weld Joint Failure Processes, SP-1621, 2001, pp. 85–93. Wang G. and M.E. Barkey, “Investigating the Spot Weld Fatigue Crack Growth Process Using X-ray Imaging,” Welding Journal, 2006, pp. 84-90. White, G., “Amplitude Demodulation Principles, V. 1.2,” DLI Engineering Corporation, Bainbridge Island, WA, July 1995.