Abstract
Flexural wave analysis has been applied to the detection and quantitative assessment of delaminations in structures. To validate analytical methods, an extensive experimental study is conducted. The test beam is of infinite length, and a delamination of prescribed length is artificially created at predetermined locations. Using two different types of excitations and measurements, the effect on the beam response of delamination length and depth, the beam material, excitation frequencies and location of excitation are analyzed. A technique for predicting the location and size of the delamination is also proposed. On each case, good comparison between analytical and experimental results is achieved.
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References
Erf, R.K., Holographic Nondestructive Testing, Academic Press, New York (1974).
Vest, C.M., Holographic Interferometry, John Wiley, New York (1979).
Shang, H.M., Chau, F.S., Tay, C.J., andToh, S.L., “Estimating the Depth and Width of Arbitrarily Oriented Disbonds in Laminates Using Shearography,”J. Nondestruct. Eval.,9 (1),19–26 (1990).
Shang, H.M., Toh, S.L., Chau, F.S., Tay, C.J., andTay, T.E., “Holographic Inspection of Laminated Plates Containing Two Fully-overlapping Identical Debonds,”J. Nondestruct. Eval.,10 (1),7–17 (1991).
Shang, H.M., Tham, L.M., andChau, F.S., “Shearographic and Holographic Assessment of Defective Laminates with Bond-lines of Different Elasticities,”ASME Trans. J. Eng. Mat. Tech.,117,322–329 (1995).
Qin, S., Shang, H.M., Giam, C.L., andTee, C.E., “Holographic Evaluation of Edge Delamination in Bars Bonded to a Rigid Support with Foamadhesive,”Trans. ASME J. Eng. Mat. Tech.,118,330–334 (1996).
Toh, S.L., Shang, H.M., Chau, F.S. andTay, C.J., “Flaw Detection in Composites Using Time-average Shearography,”Opt. Laser Tech.,23 (1),25–30 (1991).
Hung, Y.Y., “Automated Nondestructive Shearographic Inspection of Debonds in Composites Using Multi-frequency Vibrational Stressing,” Proceedings of the 1997 SEM Spring Conference, Bellevue, Washington, 98–99 (June 1997).
Hung, Y.Y., Luo, W.D., Lin, L., and Shang, H.M., “Inspection of Joined Surfaces Using Time-integrated Shearography with Multiple-frequency Sweep,” Proceedings of the 2nd International Conference on Experimental Mechanics, Singapore (Nov.–Dec. 2000).
Cawley, P., “The Impedance Method of Non-destructive Inspection,”NDT Int.,17 (2),59–65 (1984).
Cawley, P., “The Senstivity of the Mechanical Impedance Method of Non-destructive Testing,”NDT Int.,20,209–215 (1987).
Tracy, J.J. andPardoen, G.C., “Effect of Delamination on the Natural Frequencies of Composite Laminates,”J. Composite Mat.,23,1201–1215 (1989).
Silva, J.M.M.E. andGomes, A.J.M.A., “Experimental Dynamic Analysis of Cracked Free-free Beams,” EXPERIMENTAL MECHANICS,30,20–25 (1990).
Wang, J.T.S., Liu, Y.Y., andGibby, J.A., “Vibrations of Split Beams,”J. Sound Vib.,84,491–502 (1982).
Mujumdar, P.M. andSuryanarayan, S., “Flexural Vibrations of Beams with Delaminations,”J. Sound Vib.,125,441–461 (1988).
Ju, F., Lee, H.P., andLee, K.H., “Free-vibration Analysis of Composite Beams with Multiple Delaminations,”Composites Eng.,4,715–730 (1994).
Doyle, J.F. andKamle, S., “An Experimental Study of the Reflection and Transmission of Flexural Waves at Discontinuities,”ASME J. Appl. Mech.,52,669–673 (1985).
Doyle, J.F. andKamle, S., “An Experimental Study of the Reflection and Transmission of Flexural Waves at an Arbitrary T-joint,”ASME J. Appl. Mech.,54,136–140 (1987).
Liew, K.M., Jiang, L., Lim, M.K., andLow, S.C., “Experimental Detection of Disbonds and Delaminations in Honeycomb Structures,”Eng. Franct. Mech.,47,723–741 (1994).
Liew, K.M. andLim, C.S., “Analysis of Dynamic Responses of Delaminated Honeycomb Panels,”Composite Struct.,39,111–121 (1997).
Liu, G.R. andAchenbach, J.D., “A Strip Element Method for Stress Analysis of Anisotropic Linearly Elastic Solids,”ASME J. Appl. Mech.,61,270–277 (1994).
Liu, G.R. andLam, K.Y., “Characterization of a Horizontal Crack in Anisotropic Laminated Plates,”Int. J. Solids Struct.,31,2965–2977 (1994).
Liu, G.R. andLam, K.Y., “Scattering of SH Waves by Flaws in Sandwich Plates and Its Use in Flaw Detection,”Composite Struct.,34,251–261 (1996).
Liu, G.R., Lam, K.Y., andShang, H.M., “Scattering of Waves by Flaws in Anisotropic Laminated Plates,”Composites: Part B,27B,431–437 (1996).
Lam, K.Y., Liu, G.R., andWang, Y.Y., “Characterization of a Vertical Surface-breaking Crack Plates,”Computat. Acoust.,3,297–310 (1995).
Lam, K.Y., Liu, G.R., andWang, Y.Y., “Time-harmonic Response of a Vertical Crack in Plates,”Theoret. Appl. Fract Mech.,27,21–28 (1997).
Ishak, S.I., Liu, G.R., and Shang, H.M., “A Study on Mechanical Impedance Method for Characterisation of Delaminations in Laminated Material,” Proceedings of the 3rd International Symposium in Impact Engineering, 333–339 (1998).
Ishak, S.I., Liu, G.R., andLim, S.P., “Study on Characterization of Horizontal Cracks in Isotropic Beam,”J. Sound Vib.,238,661–671 (2000).
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Ishak, S.I., Liu, G.R., Lim, S.P. et al. Experimental study on employing flexural wave measurement to characterize delamination in beams. Experimental Mechanics 41, 157–164 (2001). https://doi.org/10.1007/BF02323192
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DOI: https://doi.org/10.1007/BF02323192