Simultaneous Measurement of Longitudinal and Transverse Waves Velocities Employing Spherically Focused Acoustic Transducer


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Scanning acoustic microscopy (SAM) has been applied successfully to measure leaky surface wave(LSAW) velocity from V(z) curve for material characterization. Besides LSAW, SAM produces a variety of wave modes in the material propagating with different phase speeds and features, one of which is the mode-converted ultrasound. In this paper, a novel method for simultaneous measurement of longitudinal and transverse acoustic wave velocities using the mode-converted ultrasound is developed and studied at SAM. Each ultrasound arriving at the acoustic lens with different speed and phase (or time-of-flight (TOF)) is measured by the defocused transducer to calculate longitudinal and transverse wave velocities. Simple mathematical ray analysis for the mode conversion is conducted to determine the relationship of acoustic velocities with TOF of the waves in plate. Experimental results for metals and glass show that the longitudinal and transverse wave velocities measured by the proposed method are as accurate as maximum 3% in error.



Key Engineering Materials (Volumes 321-323)

Edited by:

Seung-Seok Lee, Joon Hyun Lee, Ik Keun Park, Sung-Jin Song, Man Yong Choi




N. Y. Kim and C. K. Lee, "Simultaneous Measurement of Longitudinal and Transverse Waves Velocities Employing Spherically Focused Acoustic Transducer", Key Engineering Materials, Vols. 321-323, pp. 574-577, 2006

Online since:

October 2006




[1] H. S. Cao, et al., Determination of elastic modulus of nanocrystalline iron and titanium by means of acoustic miscroscopy, Scripta Materialia(2002), Vol 46, pp.55-60.


[2] C. Comte, J. von Stebut, Microprobe-type measurement of Young 's modulus and Poisson coefficient by means of depth sensing indentation and acoustic microscopy, Surface and Coatings Technology(2002 ), Vol. 154, pp.42-48.


[3] E. Drescher-Krasicka, Journal of acoustic Society of America(1993), Vol. 94, pp.453-464.

[4] N. Kim et al., Ultrasonic characterization of Elastic Moduli using defocused scanning acoustic microscopy, 2004 Japan-Korea Joint Workshop on Advanced Semiconductor Processes and Equipments(2004), Unzen, Japan, Nov. 18-20.

[5] M. Linda and J. Plesek, Contrast Enhancement of ultrasonic imaging of internal stresses in materials, Ultrasonics (2002), Vol. 40, pp.531-535.


[6] P. R. Murray and R. J. Dewhurst, Application of a laser/EMAT system for using shear and LS mode converted waves, Ultrasonics(2002), Vol. 40, pp.771-776.