Direct tension indicator method |
Type of Method: Direct
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Nature of signal: No Signal
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Suitability for online CM: NO
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Analysis field: Without signal processing
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Relative cost of method: Low
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Advantages: Easy implementation, simple theory, low cost.
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Disadvantages: Low accuracy, not suitable for in situ monitoring, need for specific designs for each structure.
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Strain gauges |
Type of Method: Direct
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Nature of signal: No Signal
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Suitability for online CM: NO
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Analysis field: Without signal processing
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Relative cost of method: Low
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Advantages: Easy implementation, simple theory, low cost.
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Disadvantages: Low accuracy, not suitable for in situ monitoring.
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Torque control |
Type of Method: Direct
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Nature of signal: No Signal
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Suitability for online CM: NO
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Analysis field: Without signal processing
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Relative cost of method: Low
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Advantages: Easy implementation, simple theory, low cost.
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Disadvantages: more than 50% error, depending on inspector experiences, not suitable for in situ monitoring.
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Impedance based methods |
Type of Method: Indirect
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Nature of signal: Impedance
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Suitability for online CM: YES
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Analysis field: Time or frequency.
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Relative cost of method: Relatively high
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Advantages: high sensitivity, suitable for in situ monitoring, acceptable performance for complex structures.
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Disadvantages: Relatively high cost, high size of setup, sensitivity to thermal and load fluctuations.
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Case studies: Bolted joints in pipelines (Park, et al., 2003Park, G., Sohn, H., Farrar, C. R. & Inman, D. J., 2003. Overview of piezoelectric impedance-based health monitoring and path forward. Shock and Vibration Digest, 35(6), pp. 451-463.; Park, et al., 2001), thin plates (Pavelko, et al., 2011Pavelko, V., Ozolinsh, I., Kuznetsov, S. & Pavelko, I., 2011. Structural health monitoring of aircraft structure by method of electromechanical impedance. s.l., s.n., pp. 207-223.) and experimental setups (Ritdumrongkul, et al., 2004Ritdumrongkul, C., Abe, M., Fujino, Y. & Miyashita, T., 2004. Quantitative health monitoring of bolted joints using a piezoceramic actuator-sensor. Smart materials and structures, 13(1), pp. 120-29.; Wait, et al., 2005Wait, J. R., Park, G. & Farrar, C. R., 2005. Integrated structural health assesment using piezoelectric active sensors. Shock and Vibration, Volume 12, pp. 389-405.; An & Sohn, 2012An, Y. K. & Sohn, H., 2012. Integrated impedance and guided wave based damage detection. Mechanical Systems and signal processing, Volume 28, pp. 50-62.; Mascarenas, et al., 2009Mascarenas, D. L. et al., 2009. A low-power wireless sensing device for remote inspection of bolted joints. s.l., s.n., pp. 565-575.). |
Vibration based methods |
Type of Method: Indirect
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Nature of signal: Displacement, Velocity or Acceleration
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Suitability for online CM: YES
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Analysis field: Time, frequency or time-frequency.
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Relative cost of method: Relatively low
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Advantages: Theoretical and operational simplicity, relatively low cost, acceptable accuracy.
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Disadvantages: Depending on inspector experiences, barely suitable for in situ monitoring.
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Case studies: bolted joints in robots (Trendafilova & Brussel, 2001Trendafilova, I. & Brussel, H. V., 2001. Non-linear dynamics tools for the motion analysis and condition monitoring of robot joints. Mechanical Systems and Signal Processing, 15(6), pp. 1141-1164.; Tjahjowidodo, et al., 2007Tjahjowidodo, T., Al-Bender, F. & Brussel, H. V., 2007. Experimental dynamic identification of backlash using skeleton methods. Mechanical Systems and Signal Processing, 21(2), pp. 959-972.), metal (Guarino & Hamilton, 2009Guarino, J. & Hamilton, R., 2009. Acoustic detection of bolt detorquing in structures. s.l., Acoustical Society of America.) and composite (Caccese, et al., 2004Caccese, V., Mewer, R. & Vel, S. S., 2004. Detection of bolt load loss in hybrid composite/metal bolted connections. Engineering Structures, 26(7), pp. 895-906.) structures, pipelines (Esmaeel, et al., 2012Esmaeel, R. A., Briand, J. & Taheri, F., 2012. Computational simulation and experimental verification of a new vibration-based structural health monitoring approach using piezoelectric sensors. Structural Health Monitoring, 11(2).) and experimental setups (Adams & Farrar, 2002Adams, D. & Farrar, C., 2002. Classifying linear and nonlinear structural damage using frequency domain arx models. Structural Health Moniting, 1(2), pp. 185-201.; Wit, et al., 1995Wit, C. D., Olsson, H., Astrom, K. & Lischinsky, P., 1995. A new model for control of systems with friction. Autom. Control IEEE Trans, 40(3), pp. 419-425.; Nichols, 2007Nichols, J. M., Trickey, S. T., Seaver, M., Motley, S. R., & Eisner, E. D., 2007. Using ambient vibrations to detect loosening of a compositeto- metal bolted joint in the presence of strong temperature fluctuations. Journal of Vibration and Acoustic, 129(6), pp. 710-717.; Milanese, et al., 2008Milanese, A. et al., 2008. Modeling and Detection of Joint Loosening using Output-Only Broad-Band Vibration Data. 7(4), pp. 309-328.; Razi, et al., 2013Razi, P., Esmaeel, R. A. & Taheri, F., 2013. Improvement of a vibration-based damage detection approach for health monitoring of bolted flange joints in pipelines. Structural health monitoring, 12(3), pp. 207-224.).
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Piezo active sensing method |
Type of Method: Indirect
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Type of Method: Indirect
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Type of Method: Indirect
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Analysis field: Time or frequency.
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Analysis field: Time or frequency.
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Advantages: Relatively low cost, suitable for in situ monitoring, acceptable accuracy.
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Disadvantages: High size of setup for complex structures and consequently high costs.
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Case studies: Experimental setup (Wang, et al., 2013Wang, T., Song, G., Wang, Z. G. & Li., Y. R., 2013. Proof-of-concept study of monitoring bolt connection status using a piezoelectric based active sensing method. Smart Materials and Structures, 22(8).; Chang & Yang, 2006Chang, J. & Yang, F. K., 2006. Detection of bolt loosening in C-C composite thermal protection panels: II. Experimental verification. Smart Materials and Structures, 15(2), pp. 591-599.; Doyle, et al., 2010Doyle, D., Zagrai, A., Arritt, B. & Akan, H. C., 2010. Damage detection in bolted space structures. Journal of Intelligent Material Systems and Structures, 21(3), pp. 251-264.). |
Acoustoelastic based methods |
Type of Method: Indirect
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Nature of signal: Time (TOF), Velocity (Velocity ratio) or Frequency (MRFS)
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Suitability for online CM: NO
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Analysis field: Time or frequency.
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Relative cost of method: High
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Advantages: simple and understandable theory, low sensitivity to environmental noises (TOF), No need to dismantle the bolts (Velocity ratio). |
Disadvantages: Inability to do online monitoring (TOF), need to dismantle the bolts (TOF), high sampling rate and consequently high costs. |
Case studies: bolted joints in steel structures (Liew, et al., 2006Liew, F. K., Hamdan, S. & Osman, M. S., 2006. The Relationship between the Applied Torque and Stresses in Post-Tension Structures. ECNDT.) and experimental setups (Hirao, et al., 1994Hirao, M., Ogi, H. & Fukuoka, H., 1994. Advanced ultrasonic method for measuring rail axial stresses with electromagnetic acoustic transducer. Research in Nondestructive Evaluation, 5(3), pp. 211-223.; Kawashima & Yasui, 2000Kawashima, H. & Yasui, K., 2000. Acoustoelastic measurement of bolt axial load with velocity ratio method. Italy, Rome, s.n., pp. 750-756.). |
Side band method |
Type of Method: Indirect
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Nature of signal: Displacement, Velocity or Acceleration
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Suitability for online CM: YES
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Analysis field: Frequency or Time-Frequency
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Relative cost of method: Relatively high
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Advantages: High accuracy, suitable for in situ monitoring and low sensitivity to environmental noises.
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Disadvantages: Complicated theory, relatively high cost
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Case studies: Bolted joints in plates (Meo & Amerini, 2011Meo, M. & Amerini, F., 2011. Structural health monitoring of bolted joints using linear and nonlinear acoustic/ultrasound methods. Structural health monitoring, Volume 10, pp. 659-672.; Amerini, et al., 2010) and experimental setups (Meyer & Adams, 2015Meyer, J. J. & Adams, D. E., 2015. Theoretical and experimental evidence for using impact modulation to assess bolted joints. Nonlinear Dynamics.). |