Los Alamos National LaboratoryEngineering Institute
Addressing national needs by fostering specialized recruiting and strategic partnerships

Structural Health Monitoring Publications

Publications are organized by topic.

Contact  

  • Institute Director
  • Charles Farrar
  • (505) 663-5330
  • Email
  • UCSD EI Director
  • Michael Todd
  • (858) 534-5951
  • Program Administrator
  • Ellie Vigil
  • (505) 667-2818
  • Email
  • Office Administrator
  • Vacant

Structural Health Monitoring is the process of implementing a damage detection strategy for aerospace, civil and mechanical engineering infrastructure is referred to as Structural Health Monitoring (SHM).

The SHM process involves the observation of a system over time using periodically sampled dynamic response measurements from an array of sensors. The extraction of damage-sensitive features from these measurements and the statistical analysis of these features is then used to determine the current state of system health.

For long term SHM, the output of this process is periodically updated information regarding the ability of the structure to perform its intended function in light of the inevitable aging and degradation resulting from operational environments. After extreme events, such as earthquakes or blast loading, SHM is used for rapid condition screening and aims to provide, in near real time, reliable information regarding the integrity of the structure.

Impedance Method
  • S.G. Taylor, K. M. Farinholt, G. Park, C. R. Farrar, M. D. Todd, and J.-R. Lee, “Incipient crack detection in composite wind turbine blades,” accepted for publication in J. of Intelligent Material Systems and Structures, 2013.
  • H-J Shin, C-Y Yun, G. Park, K. M. Farinholt, J-R Lee, C-Y Park, S-M Jun and C. R. Farrar, “Assessing joint integrity of a lug assembly using piezoelectric active sensors,” Structural Control Health Monitoring, 2012; 19 pp. 621–631.
  • A. B. Thien, G. Park and C. R. Farrar, “Health Monitoring of Pipeline Systems using Macro-fiber Composite Active-Sensors,” Int. J. of Steel Structures, 2007; 7(1), pp.33-48.
  • A. C. Rutherford, G. Park and C. R. Farrar, “Nonlinear Feature Identification Based on Self-sensing Impedance Measurement for Structural Health Assessment,” Mechanical Systems and Signal Processing, 2007; 21(1), pp. 322-333.
  • J. R. Wait, G. Park, C. R. Farrar, “Integrated Structural Health Assessment using Piezoelectric Active Sensors,” Shock and Vibration, 2005; 12(6), pp.389-405.
  • Fasel, T. R., H. Sohn, G. Park, and C. R. Farrar “Active Sensing using Impedance-Based ARX Models and Extreme Value Statistics for Damage Detection,” Earthquake Engineering and Structural Dynamics, 2005; 34(1) pp. 763-785.
  • G. Park, A. C. Rutherford, H. Sohn and C. R. Farrar, “An Outlier Analysis Framework for Impedance-based Structural Health Monitoring,” J. of Sound and Vibration, 2005; 286(1-2) pp. 229-250.
  • G. Park, H. Sohn, C. R. Farrar and D. J. Inman, “Overview of Piezoelectric Impedance-Based Health Monitoring and Path Forward,” Shock and Vibration Digest, 2003; 35(6) pp. 451-463.
Guided Waves
  • S.G. Taylor, K. M. Farinholt, G. Park, C. R. Farrar, M. D. Todd, and J.-R. Lee, “Incipient crack detection in composite wind turbine blades,” accepted for publication in J. of Intelligent Material Systems and Structures, 2013.
  • G. Park, J-S Lee, C-G-Park, and C. R. Farrar, “Use of Relative Baseline Features of Guide Waves for In-Situ Structural Health Monitoring,” J. of Intelligent Materials Systems and Structures, 2011; 22 (2) pp. 175-189  
  • T.G. Overly, L.D. Jacobs, K. M. Farinholt, G. Park, C.R. Farrar, E.B. Flynn, M.D.Todd, “Developing an Integrated Software Solution for Active-Sensing SHM,” Smart Structures and Systems, 2009; 5(4), pp. 457-468.
  • A. B. Thien, G. Park and C. R. Farrar, “Health Monitoring of Pipeline Systems using Macro-fiber Composite Active-Sensors,” Int. J. of Steel Structures, 2007; 7(1), pp.33-48.
  • F. Lanza di Scalea, H. Matt, H., I. Bartoli, S.  Coccia, G. Park and C. R. Farrar, “Health Monitoring of UAV Wing Skin-to-Spar Joints using Guided Waves and macro Fiber composite Transducers,” J. of Intelligent Material, Systems and Structures, 2007; 18(4), pp. 373-388.
  • H. Sohn, H. W. Park, K. H.  Law and C. R. Farrar, “Damage Detection in Composite Plates by Using an Enhanced Time Reversal Method,” J. of Aerospace Engineering, 2007; 20(3), pp. 141-151.
  • H. W. Park, H. Sohn, K. H.  Law and C. R. Farrar, “Time Reversal Active Sensing for Health Monitoring of a Composite Plate,” J. of Sound and Vibration, 2007; 302(1-2), pp. 50-66.  
  • G. Park, C. R. Farrar, F. Lanza. di Scalea and S. Coccia “Performance Assessment and Validation of Piezoelectric Active-Sensors in Structural Health Monitoring,” J. of Smart Material and Structures, 2006; 15(6), pp. 1673-168.
  • H. Sohn, H. W. Park, K. Law and C. R. Farrar, “Combination of a Time Reversal Process and a Consecutive Outlier Analysis for Baseline-free Damage Diagnosis,” J. of Intelligent Material Systems and Structures, 2007; 18(4), pp. 335-346.
  • H. Sohn, G. Park, J. Wait, N. P. Limback and C. R. Farrar, “Wavelet-Based Active Sensing for Delamination Detection in Composite Plates,” J. of Smart Material and Structures, 2004; 13(1) pp. 153 - 160.
Modal Properties
  • D. E. Adams, J. White, M. Rumsey and C. R. Farrar “Structural Health Monitoring of Wind Turbines: Method and Application to a HAWT,” Wind Energy, 2011; 14(4), pp. 603-623.
  • S. W. Doebling, and C. R. Farrar, "Estimation of Statistical distributions for Modal Parameters Identified from Averaged Frequency Response Function Data," Journal of Vibration and Control, 2001; 7(4), pp.603-624.
  • T. A. Duffey, Doebling, S. W., Farrar, C. R., Baker, W. E., and Rhee, W. H., "Vibration-Based Damage Identification in Structures Exhibiting Axial and Torsional Response," J. of Vibration and Acoustics, 2001; 123(1) pp. 84-91
  • C. R. Farrar and D. V. Jauregui, "A Comparative Study of Damage Identification Algorithms Applied to a Bridge: Part I, Experimental" J. of Smart Materials and Structure, 1998; 7(5), pp.704-719.
  • C. R. Farrar and D. V. Jauregui, "A Comparative Study of Damage Identification Algorithms Applied to a Bridge: Part II, Numerical" J. of Smart Materials and Structure, 1998; 7(5), pp.720-731.
  • C. R. Farrar and S. W. Doebling, “Vibration-Based Health Monitoring and Model Refinement of Civil Engineering Structures,” Technology, 2000; 7, pp. 43-54.
  • P. J. Cornwell, S. W. Doebling and C. R. Farrar, “Application of the Strain Energy Damage Detection Method to Plate-like Structures,” J. of Sound and Vibration, 1999; 224(2), pp.359-374.
Model Updating
  • S. W. Doebling, C. R. Farrar, M. B. Prime and D. W. Shevitz, "A Review of Damage Identification Methods that Examine Changes in Dynamic Properties," Shock and Vibration Digest 1998; 30(2), pp. 91-105. 
Sensing Technologies
  • N. Sharp, A. Kuntz, C. Brubaker, S. Amos, W. Gao, G. Gupta, A. Mohite, C. Farrar, and D. Mascareñas, “A bio-inspired asynchronous skin system for crack detection applications" accepted for publication in Smart Materials and Structures.
  • Stull, C.J., Taylor, S. G., Wren, J., Mascarenas, D.L., Farrar, C. R., “Real-Time Condition Assessment of the Raptor Telescope System,” accepted for publication in ASCE J. of Structural Engineering (theme issue on applications of structural health monitoring to in situ structures).
  • J. H. Park, J.T. Kim, G.S. Hong, D. Mascarenas, J. P. Lynch, “Autonomous smart sensor nodes for global and local damage detection of prestressed concrete bridges based on accelerations and impedance measurements,” Smart Structures and Systems, 2010, 6(5-6) pp 711-730.
  • S. G. Taylor, K. M, Farinholt, G. Park, M. D. Todd and C. R. Farrar, “Multi-scale wireless sensor node for health monitoring of civil infrastructure and mechanical systems," Smart Structures and Systems, 2010; 6(5-6), pp. 661-673.
  • K.M. Farinholt, N. Miller, W. Sifuentes, J. MacDonald, G. Park, and C.R. Farrar, “Energy Harvesting and Wireless Energy Transmission for Embedded SHM Sensor Nodes," International Journal of Structural Health Monitoring, 2010; 9(3), pp.269-280.
  • D. L. Mascarenas, E. Flynn, M. D. Todd, T. G. Overly, K. M. Farinholt, G. Park, C. R. Farrar, “Development of Capacitance-Based and Impedance-Based Wireless Sensors and Sensor Nodes for Structural Health Monitoring Applications,” J. of Sound and Vibration, 2010; 329(12), pp. 2410-2420.
  • D. L. Mascarenas, E. Flynn, M. D. Todd, T. G. Overly, K. M. Farinholt, G. Park, C. R. Farrar, ”Experimental Studies of using Wireless Energy Transmission for Powering Embedded Sensor Nodes,” J. of Sound and Vibration, 2010; 329(12), pp. 2421-2433.
  • D. Mascarenas, E. Flynn, C. Farrar, G. Park, and M. Todd, “A mobile host approach for wireless powering and interrogation of structural health monitoring sensor networks,” IEEE Sensors J., 2009; 9(12), pp. 1719-1726.
  • K. M. Farinholt, N. Pedrazas, D. Schluneker, D. Burt and C. Farrar, “An Energy Harvesting Comparison of Piezoelectric and Ionically Conductive Polymers,” J. of Intelligent Materials Systems and Structures, 2009; 20(5), pp. 633-642.
  • K. M. Farinholt, G. Park and C. R. Farrar, “RF Energy Transmission for a Low-Power Wireless Impedance Sensor Node,” IEEE Sensors J., 2009; 9(7), pp. 793-800.
  • T. G. Overly, K. M. Farinholt, G. Park and C. R. Farrar, “Piezoelectric Active-Sensor Diagnostics and Validation Using Instantaneous Baseline Data,” IEEE Sensor J., 2009; 9(11), pp. 1414-1421.
  • D. L. Mascarenas, G. Park, G., K. M. Farinholt, M. D. Todd and C. R. Farrar, "A Low-Power Wireless Sensing Device for Remote Inspection of Bolted Joints," J. of Aerospace Engineering, Part G of the Proc. of the Institution of Mechanical Engineers, 2009; 233(5), pp. 565-575.
  • S. G. Taylor, K. M. Farinholt, E. B. Flynn, E. Figueiredo, D. L. Mascarenas, E. A. Moro, G. Park, M. D. Todd, C. R. Farrar, “Mobile-agent based wireless sensing network for structural monitoring applications,” Measurement Science and Technology, 2009; 20(4), pp. 1-14.
  • Park, S., Park, G., Yun, C.B., Farrar, C.R., “Sensor Self-Diagnosis Using a Modified Impedance Model for Active-Sensing Structural Health Monitoring,” Int. J. of Structural Health Monitoring, 2009; 8(1), pp. 71-82.
  • D.M. Mascarenas, E.B. Flynn, M.D. Todd, G. Park, G., C.R. Farrar, “Wireless Sensor Technologies for Monitoring Civil Structures,” Sound and Vibration, April, 2008, pp. 16-20.
  • T. G. Overly, G. Park, K. M. Farinholt, and C. R. Farrar, “Development of an Extremely Compact Impedance-Based Wireless Sensing Device,” Smart Materials and Structures, 2008; 17(6), pp. 065011.
  • D. L. Mascarenas, G. Park, M. D. Todd and C. R. Farrar, “Development of an Impedance-based Wireless Sensor Node for Structural Health Monitoring, Smart Materials and Structures, 2007; 16(6), pp. 2137–2145.  
  • G. Park, T. Rosing, M. D. Todd, C. R. Farrar and W. Hodgkiss, “Energy Harvesting for Structural Health Monitoring Sensor Networks, ASCE J. of Infrastructure Systems, 2008;14(1), pp. 64-79.
  • A. B. Thien, G. Park and C. R. Farrar, “Health Monitoring of Pipeline Systems using Macro-fiber Composite Active-Sensors,” Int. J. of Steel Structures, 2007; 7(1), pp.33-48.
  • G. Park, C. R. Farrar, F. Lanza. di Scalea and S. Coccia “Performance Assessment and Validation of Piezoelectric Active-Sensors in Structural Health Monitoring,” J. of Smart Material and Structures, 2006; 15(6), pp. 1673-1683
  • C. R. Farrar, D. W. Allen, G. Park, S. Ball and M. Masquelier, “Coupling Sensing Hardware with Data Interrogation Software for Structural Health Monitoring, Shock and Vibration, 2006; 13(4-5), pp. 519-530.
  • G. Park, C. R. Farrar, A. C. Rutherford, and A. N. Robertson, “Piezoelectric Active Sensor Self-diagnostics using Electrical Admittance Measurements,” ASME J. of Vibrations and Acoustics, 2006; 128(4), pp.469 - 476.
  • C. R. Farrar, G. Park, D. W. Allen and M. D. Todd, “Sensor Network Paradigms for Structural Health Monitoring,” J. of Structural Control and Health Monitoring, 2006; 13(1), pp. 210–225.
  • J. R. Dove, G. Park, and C. R. Farrar, “Hardware Design of Hierarchal Active-Sensing Networks for Structural Health Monitoring,” Smart Materials and Structures 2006; 15(1), pp.139-146.
  • G. E. Simmers, J. Hodgkins, D. Mascarenas, G. Park, and H. Sohn, “Improved Piezoelectric Self-Sensing Actuation,” Journal of Intelligent Material Systems and Structures, 2004, 15(12), pp. 941-953, 2004.
  • J. P Lynch, K. H. Law, A. S. Kiremidjian, E. Carryer, C. R. Farrar, H. Sohn, D. W. Allen, B Nadler, and J. R. Wait, “Design and Performance Validation of a  Wireless Sensing Unit for Structural Monitoring Applications,” Int. J. of Structural Engineering and Mechanic, 2004; 17(3-4) pp. 393 – 408.
  • N. Tanner, J. Wait, C. R. Farrar and H. Sohn, “Structural Health Monitoring Using Modular Wireless Sensors,” J. of Intelligent Material Systems and Structures, 2003; 14(1) pp.43-56.
  • C. R. Farrar, T. Darling, and A. Migliori, "Microwave Interferometers for Remote Non-Contact Vibration Measurements on Large Structures," Mechanical Systems and Signal Processing, 1999; 13(2), pp 241-253.
Time Series Analysis, Machine Learning, and Statistical Methods
  • Dervilies, N., Choi, M., Taylor, S.G., Barthorpe, R.J., Park, G., Farrar, C.R., Worden, K. “On damage diagnosis for a wind turbine blade using pattern recognition,” accepted for publication in J. of Sound and Vibration.
  • D. L. Mascarenas, A. Cattaneo, J. Theiler, C. R. Farrar, “Compressed Sensing Techniques for Detecting Damage in Structures, Int. J. of Structural Health Monitoring, 2013; 12(4) pp. 325-338.
  • E. Figueiredo, G. Park, J. Figueiras, C. R. Farrar and K. Worden, “Data Normalization for Nonlinear Damage Detection under Operational and Environmental conditions,” accepted for publication in  Int. J. of Structural Health Monitoring
  • E. Figueiredo, G. Park, K. M. Farinholt, C. R. Farrar and J-R Lee, “Use of Time-Series Predictive Models for Piezoelectric Active-Sensing in Structural Health Monitoring Applications,” J. of Vibration and Acoustics, 2012; 134(4) pp. 041014.1-10.
  • Stull, C.J., Taylor, S. G., Wren, J., Mascarenas, D.L., Farrar, C. R., “Real-Time Condition Assessment of the Raptor Telescope System,” accepted for publication in ASCE J. of Structural Engineering (theme issue on applications of structural health monitoring to in situ structures).
  • E. Figueiredo, G. Park, C. R. Farrar, K. Worden and J. Figueiras “Machine Learning Algorithms for Damage Detection under Operational and Environmental Variability,” Int. J. of Structural Health Monitoring, 2011; 10(6), pp. 559-572
  • Z Q Lang, G Park, C R Farrar, M D Todd, Z Mao, L Zhao, and K Worden “Transmissibility of Nonlinear Output Frequency Response Functions with Application in Detection and Location of Damage in MDOF Structural Systems,” International Journal of Nonlinear Mechanics, 2011; 46(6), pp. 841-853.
  • E. Figueiredo, J. Figueiras, G. Park, and C. R. Farrar, “Influence of Model Order Selection on Damage Detection,” Int. J. of Computer-Aided Civil and Infrastructure Engineering, 2011; 26(3), pp. 225-238.
  • L. Bornn, C. R. Farrar and G. Park, “Damage Detection in Initially Nonlinear Systems,” Int. J. of Engineering Science, 2010; 48(10), pp. 909-920.
  • E. Figueiredo, M. D. Todd, C. R. Farrar and E. Flynn “Autoregressive Modeling with State-Space Embedding Vectors for Damage Detection Under Operational Variability,” Int. J. of Engineering Science, 2010;48(10), pp. 822-834.
  • M. R. Hernandez-Garcia, S. F. Masri, R. Ghanem, E. Figueiredo and C. R. Farrar , “A structural decomposition approach for detecting, locating, and quantifying nonlinearities in chain-like systems, Journal of Structural Control and Health Monitoring, 2010;17 (7), pp. 761-777.
  • M. R. Hernandez-Garcia, S. F. Masri, R. Ghanem, E. Figueiredo and C. R. Farrar, “An experimental study of change detection in uncertain chain-like systems", Journal of Sound and Vibration, 2010; 329(1), pp. 2395–2409.
  • L. Bornn, C. R. Farrar, G. Park and K. M. Farinholt, “Structural Health Monitoring Using Autoregressive Support Vector Machines, ASME Journal of Vibration and Acoustic, 2009; 131(2), pp. 021004.
  • G. Park, A. C. Rutherford, J. R. Wait, B. R. Nadler, C. R. Farrar and T. N Claytor, “High-Frequency Response Functions for Composite Plate Monitoring with Ultrasonic Validation,” AIAA Journal, 2005; 43(11), pp. 2431-2437.
  • H. Sohn, K. Worden, D. Allen and C. R. Farrar, “Structural Damage Classification Using Extreme Value Statistics,” J. of Dynamic Systems, Measurement, and Control, 2005; 127(1) pp.125-132.
  • H. Sohn, A. N. Robertson and C. R. Farrar, “Holder Exponent Analysis for Discontinuity Detection,” Int. J. of Structural Engineering and Mechanic, 2004; 17(3-4) pp. 409 – 428.
  • A. N. Robertson, C. R. Farrar and H. Sohn, “Singularity Detection for Structural Health Monitoring Using Holder Exponents,” Mechanical Systems and Signal Processing, 2003; 17(6) pp. 1163-1184.
  • H. Sohn, D. W. Allen, K. Worden, and C. R. Farrar, “Statistical Damage Classification Using Sequential Probability Ratio Tests,” Int. J. of Structural Health Monitoring, 2003; 2(1) pp. 57- 74.  
  • H. Sohn, K. Worden, and C. R. Farrar, “Statistical Damage Classification under Changing Environmental and Operational Conditions,” J. of Intelligent Materials Systems and Structures, 2003; 13(9) pp.561-574.  
  • K. Worden, H. Sohn, and C. R. Farrar, “Novelty Detection in a Changing Environment: Regression and Interpolation Approaches,” J. of Sound and Vibration, 2002; 258(4) pp.741-761.
  • D. Adams and C. R. Farrar, “Classifying Linear and Nonlinear Structural Damage Using Frequency Domain ARX Models,” Int. J. of Structural Health Monitoring, 2002; 1(2) pp. 183- 201.
  • H. Sohn and C. R. Farrar, “Damage Diagnosis Using Time Series Analysis of Vibration Signals,” Journal of Smart Materials and Structures, 2001; 10(3), pp.446-451.
  • H. Sohn, C. R. Farrar, N. F. Hunter, and K. Worden, “Structural Health Monitoring Using Statistical Pattern Recognition Techniques,” ASME Journal of Dynamic Systems, Measurement and Control Special Issue on Identification of Mechanical Systems, 2001; 123(4), pp. 706 -711.
  • M. L. Fugate, H. Sohn, and C. R. Farrar, “Vibration-Based Damage Detection Using Statistical Process Control,” Mechanical Systems and Signal Processing, 2001; 15(4) pp.707-721.
  • C. R. Farrar, S. W. Doebling and D. A. Nix, “Vibration-Based Structural Damage Identification” Philosophical Transactions of the Royal Society: Mathematical, Physical & Engineering Sciences, 2001; 359(1778) pp. 131 – 149.
  • H. Sohn, J. Czarnecki, and C. R. Farrar, “Structural Health Monitoring Using Statistical Process Control,” J. of Structural Engineering, ASCE, 2000, 126(11); pp. 1356-1363.
Optimization & Robustness
  • M. Pasquali, C.J. Stull and C.R. Farrar, “Info-gap robustness of an input signal optimization algorithm for damage detection,” accepted for publication in Mechanical Systems and Signal Processing.
  • C. J. Stull, F. M. Hemez and C. R. Farrar, “On Assessing the Robustness of Structural Health Monitoring Technologies,” Int. J. of Structural Health Monitoring, 2012; 11(6) pp. 712-723.
  • C. C. Olson, M. D. Todd, K. Worden and C. R. Farrar “Improving Excitations for Active Sensing in Structural Health Monitoring via Evolutionary Programming,” ASME J. of Vibration and Acoustics, 2007; 129(6), pp. 784-802 
Summaries & Reviews
  • D. Dhital, J. R. Lee, C.R. Farrar and D. Mascareñas, “A review of flaws and damage in space launch vehicles: Motors and engines,” J. of Intelligent Material Systems and Structures, 2014, 25(5), pp. 524-540.
  • K. Worden, C. R. Farrar, G. Manson and G. Park “The Fundamental Axioms of Structural Health Monitoring,” Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2007; 463(2082), pp.1639-1664.
  • K. Worden, C. R. Farrar, J. Hayward and M. D. Todd “A Review of Nonlinear Dynamics Applications to Structural Health Monitoring,” J. of Structural Control and Health Monitoring, 2007; 15(4), pp. 540-567.  
  • C. R. Farrar and K. Worden “An Introduction to Structural Health Monitoring,” Philosophical Transactions of the Royal Society A, 2007; 365(1851), pp. 303-315.
  • C. R. Farrar and N. Lieven “Damage Prognosis: The Future of Structural Health Monitoring,” Philosophical Transactions of the Royal Society A, 2007; 365(1851), pp.623-632.
  • C. R. Farrar, D. W. Allen, G. Park, S. Ball and M. Masquelier, “Coupling Sensing Hardware with Data Interrogation Software for Structural Health Monitoring, Shock and Vibration, 2006; 13(4-5), pp. 519-530.  
  • C. R. Farrar, G. Park, D. W. Allen and M. D. Todd, “Sensor Network Paradigms for Structural Health Monitoring,” J. of Structural Control and Health Monitoring, 2006; 13(1), pp. 210–225.
  • C. R. Farrar, H. Sohn, G. Park, and F. M. Hemez, “Developing Impact and Fatigue Damage Prognosis Solutions for Composites,” JOM-Journal of Minerals, Metals & Materials Society, 2004, 56(3) pp. 40-43.  
  • G. Park, H. Sohn, C. R. Farrar and D. J. Inman, “Overview of Piezoelectric Impedance-Based Health Monitoring and Path Forward,” Shock and Vibration Digest, 2003; 35(6) pp. 451-463. 
  • C. R. Farrar, S. W. Doebling and D. A. Nix, “Vibration-Based Structural Damage Identification” Philosophical Transactions of the Royal Society: Mathematical, Physical & Engineering Sciences, 2001; 359(1778) pp. 131 – 149.
  • C. R. Farrar and S. W. Doebling, “Vibration-Based Health Monitoring and Model Refinement of Civil Engineering Structures,” Technology, 2000; 7, pp. 43-54.
  • C. R. Farrar, and T. A. Duffey, "Vibration-Based Damage Detection in Rotating Machinery," Key Engineering Materials, 1999; 167-168, pp. 224-235.  
  • S. W. Doebling, C. R. Farrar, M. B. Prime and D. W. Shevitz, "A Review of Damage Identification Methods that Examine Changes in Dynamic Properties," Shock and Vibration Digest 1998; 30(2), pp. 91-105.