Dispersion Behaviors of ASF Modes Propagating along Wedges Tips with Coatings
Acoustic sensors frequently rely on the detection of small mass changes that results from binding of a coated layer coupled to the active sensor surface. Anti-symmetric flexural (ASF) modes are anti-symmetric type of guided waves propagating along the tip of wedge-shaped waveguides. Like surface acoustic waves, ASF can be a potential candidate for the purpose of acting as acoustic sensors. This paper employs a combined numerical and experimental study for the dispersion behaviors of ASF modes propagating along wedge tips with a layer of coating. The numerical study is based on finite element method while the experimental study employs a laser ultrasound technique. Velocity for the ASF mode propagating along the wedge tip with a slower coating is found out to start at the ASF velocity of the matrix wedge at the low frequency regime, and gradually influenced by the coating as the frequency increases. Enhanced loaded effects from the coating are founded due to the wedge tip geometry. In general, the numerical results show good agreement with the measurements.
KeywordsSurface Acoustic Wave Apex Angle Dispersion Behavior Signal Processing Scheme Wedge Sample
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- 3.Lagasse, P.E., Mason I.M., Ash E.A.: Microwave Theory and Technique, IEEE Trans. Sonics Ultrason. 20 143-154 (1973).Google Scholar
- 4.McKenna, J., Boyd, G.D., Thurston R.N.: Plate theory solution for guided flexural acoustic waves along the tip of a wedge, IEEE Trans. Sonics and Ultrasonics. 21 178-186 (1974).Google Scholar
- 5.Krylov, V.V., Shanin, A.V.: Scattering of an acoustic wedge wave by a shallow notch. Sov. Phys. Acoust. 37 65 (1991).Google Scholar
- 8.Chamuel, J.R.: Flexural edge waves along free and immersed elastic wave guides. Review of Progress in Quantitative Nondestructive Evaluation 16 129-136 (1997).Google Scholar
- 12.Farnell, G.W., Adler, E.L. Physical Acoustics, Mason, W.P., Thurston R.N., (eds.), 9, 35 Academic Press, New York (1972).Google Scholar