This article deals with the monitoring of the composite wing skin-to-spar joint in unmanned aerial vehicles using ultrasonic guided waves. The study investigates simulated wing skin-to-spar joints with two different types of bond defects, namely poorly cured adhesive and disbonded interfaces. The bond-sensitive feature considered is the ultrasonic strength of transmission through the joints. The dispersive wave propagation problem is studied numerically by a semi-analytical finite element method that accounts for viscoelastic damping, and experimentally by ultrasonic testing that uses highly durable, flexible macro fiber composite transducers. The discrete wavelet transform is also employed to de-noise and compress the ultrasonic measurements. Both numerical and experimental tests confirm that the ultrasonic strength of transmission increases across the defected bonds.
Abbate, A., Koay, J., Frankel, J., Schroeder, S.C. and Das, P.1994. ``Application of Wavelet Transform Signal Processor to Ultrasound,'' In: Proceedings Ultrasonic Symposium , 94CH3468-6:1147—1152.
2.
Barbezat, M., Brunner, A.J., Flüeler, P., Huber, C. and Kornmann, X.2004. ``Acoustic Emission Sensor Properties of Active Fibre Composite Elements Compared with Commercial Acoustic Emission Sensors,'' Sensors and Actuators A: Physical, 114:13—20.
3.
Bartoli, I., Marzani, A., Lanza di Scalea, F. and Viola, E. 2006. ``Modeling Wave Propagation in Damped Waveguides of Arbitrary Cross-section,'' Journal of Sound and Vibration (available on-line at doi: 10.1016/j.jsv.2006.01.021).
4.
Bernard, A., Lowe, M.J.S. and Deschamps, M.2001. ``Guided Waves Energy Velocity in Absorbing and Non-absorbing Plates,'' Journal of the Acoustical Society ofAmerica, 110:186—196.
5.
Bevan, J.S. and Mei, C.2001. ``Piezoceramic Actuator Placement for Structural Acoustic and Vibration Control of Flat and Curved Panels,'' In: ProceedingsSPIE, 4327:698—708.
6.
Brunner, A.J., Barbezat, M., Flüeler, P. and Huber, C.2004. ``Composites from Piezoelectric Fibers as Sensors and Emitters for Acoustic Applications,'' Journal of Acoustic Emission, 22:127—137.
7.
Chang, Z. and Mal, A.K.1995. ``A Global-local Method for Wave Propagation Across a Lap Joint,'' Numerical Methods in Structural Mechanics, 204:1—11.
8.
Finnveden, S.2004. ``Evaluation of Modal Density and Group Velocity by a Finite Element Method,''Journal of Sound and Vibration, 273:51—75.
9.
Gavrić, L.1995. ``Computation of Propagative Waves in Free Rail using a Finite Element Technique,''Journal of Sound and Vibration , 185:531—543.
10.
Gu, H., Lloyd, G.M. and Wang, M.L.2005. ``Interdigitated PVDF Transducers for Lamb Wave Generation and Reception,'' In: ProceedingsSPIE, Vol. 5765, pp. 302—312.
11.
Hay, T.R., Wei, L., Rose, J.L. and Hayashi, T.2003. ``Rapid Inspection of Composite Skin-honeycomb Core Structures with Ultrasonic Guided Waves,'' Journal ofComposite Materials , 37:929—939.
12.
Hayashi, T., Song, W.J. and Rose, J.L.2003. ``Guided Wave Dispersion Curves for a Bar with an Arbitrary Cross-section, a Rod and Rail Example,'' Ultrasonics, 41:175—183.
13.
Heller, K., Jacobs, L.J. and Qu, J.2000. ``Characterization of Adhesive Bond Properties Using Lamb Waves,'' NDT&E International, 33:555—563.
14.
Kundu, T., Maji, A., Ghosh, T. and Maslov, K.1998. ``Detection of Kissing Bonds by Lamb Waves,''Ultrasonics, 35:573—580.
15.
Lanza diScalea, F., Bonomo, M. and Tuzzeo, D.2001. ``Ultrasonic Guided Wave Inspection of Bonded Lap Joints: Noncontact Method and Photoelastic Visualization,'' Research in Nondestructive Evaluation, 13:153—171.
16.
Lanza diScalea, F., Rizzo, P. and Marzani, A.2004. ``Propagation of Ultrasonic Guided Waves in Lap-shear Adhesive Joints: Case of Incident a0 Lamb Wave,'' Journal of the Acoustical Society of America, 115:146—156.
17.
Lowe, M.J.S. and Cawley, P.1994. ``The Applicability of Plate Wave Techniques for the Inspection of Adhesive and Diffusion Bonded Joints,'' Journal of NondestructiveEvaluation, 13:185—200.
18.
Lowe, M.J.S., Challis, R.E. and Chan, C.W.2000. ``The Transmission of Lamb Waves Across Adhesively Bonded Lap Joints,'' Journal of the Acoustical Society ofAmerica , 107:1333—1345.
19.
Mal, A.K., Xu, P.C. and Bar-Cohen, Y.1990. ``Leaky Lamb Waves for the Ultrasonic Nondestructive Evaluation of Adhesive Bonds,'' ASME Journal of Engineering Materials Technology, 112:255—259.
20.
Mal, A.K., Chang, Z. and Guo, D.1996. ``Lap Joint Inspection using Plate Waves,'' In: ProceedingsSPIE, Vol. 2945, pp. 128—137.
21.
Mallat, S.G.1999. A Wavelet Tour of Signal Processing, Academic Press, New York, NY.
22.
Monkhouse, R.S.C., Wilcox, P.D. and Cawley, P.1997. ``Flexible Interdigital PVDF Transducers for the Generation of Lamb Waves in Structures,'' Ultrasonics, 35:489—498.
23.
Mukdadi, O.M. and Datta, S.K.2003. ``Transient Ultrasonic Guided Waves in Layered Plates with Rectangular Cross Section,'' Journal ofApplied Physics , 93:9360—9370.
24.
Mukdadi, O.M., Desai, Y.M., Datta, S.K., Shah, A.H. and Niklasson, A.J.2002. ``Elastic Guided Waves in a Layered Plate with Rectangular Cross Section,'' Journal of the Acoustical Society ofAmerica , 112:1766—1779.
25.
Nagy, P.B. and Adler, L.1989. ``Nondestructive Evaluation of Adhesive Joints by Guided Waves,'' Journal ofApplied Physics, 66:4658—4663.
26.
Neau, G., Lowe, M.J.S. and Deschamps, M.2002. ``Propagation of Lamb Waves in Anisotropic and Absorbing Plates: Theoretical Derivation and Experiments,'' Review of Progress in QNDE, 21:1062—1068.
27.
Paget, C.A., Grondel, S., Levin, K. and Delebarre, C.2003. ``Damage Assessment in Composites by Lamb Waves and Wavelet Coefficients,'' Smart Materials and Structures, 12:393—402.
28.
Rizzo, P. and Lanza di Scalea, F.2005. ``Ultrasonic Inspection of Multi-wire Steel Strands with the Aid of the Wavelet Transform,'' Smart Materials and Structures, 14:1—11.
29.
Rose, J.L., Rajana, K.M. and Hansch, M.K.T.1995. ``Ultrasonic Guided Waves for NDE of Adhesively Bonded Structures,'' Journal ofAdhesion, 50:71—82.
30.
Rose, J.L., Zhu, W. and M. Zaidi.1998. ``Ultrasonic NDT of Titanium Diffusion Bonding with Guided Waves,'' MaterialsEvaluation, 56:535—539.
31.
Schoenecker, A.J., Gebhardt, S.E., Rödig, T., Keitel, U., Bruckner, B., Schnetter, J. and Daue, T.2005. ``Piezocomposite Transducers for Smart Structures Applications ,'' In: ProceedingsSPIE, Vol. 5764, pp. 34—41.
32.
Seifried, R., Jacobs, L.J. and Qu, J.2002. ``Propagation of Guided Waves in Adhesive Bonded Components ,'' NDT&E International, 35:317—328.
33.
Staszewski, W.2002. ``Intelligent Signal Processing for Damage Detection in Composite Materials,'' CompositesScience and Technology, 62:941—950.
Thien, A.B., Chiamori, H.C., Ching, J.T., Wait, J.R. and Park, G.2005. ``Piezoelectric Active Sensing for Damage Detection in Pipeline Structures,'' In: Proceedings 23rd International Modal Analysis Conference, Orlando, FL, pp. 323—336.
36.
Wilkie, W.K., Bryant, R.G., High, J.W., Fox, R.L., Hellbaum, R.F., Jalink, A., Little, B.D. and Mirick, P.H.2000. ``Low-cost Piezocomposite Actuator for Structural Control Applications,'' In: Proceedings SPIE's 7th Annual International Symposium on Smart Structures and Materials, Newport Beach, CA, pp. 323—334.
37.
Williams, R.B., Park, G., Inman, D.J. and Wilkie, W.K.2002. ``An Overview of Composite Actuators with Piezoceramic Fibers,'' In: Proceedings 20th International Modal Analysis Conference, Los Angeles, CA.
