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Official Journal of the Japan Wood Research Society

Effect of coupling media on velocity and attenuation of ultrasonic waves in Brazilian wood


Coupling media are necessary to ensure that transducers bond to wood specimens to minimize coupling losses and improve the accuracy of ultrasonic measurements. There are several types of coupling media available, and the optimal choice is not known. In this work, we analyzed the results of ultrasonic wave attenuation for 0.1-MHz longitudinal and transverse transducers with six different materials as coupling media in nine species of Brazilian wood with densities in the range 700–1170 kg/m3. Tests were performed using constant pressure on the transducer and with wave propagation in the longitudinal direction. For transverse transducers, the polarization was in the radial and tangential directions. The results were analyzed statistically and showed that, for attenuation in both longitudinal and transverse waves, the material used for coupling had significant effects, whereas the wood species had no effect. For longitudinal waves, the statistical evaluation showed that the coupling material performance was strongly dependent on the species of wood, but it was not possible to observe any tendency of behavior associated with specific anatomical properties.


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Correspondence to Raquel Gonçalves.

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Part of this article was presented at the 16th International Symposium on Nondestructive Testing and Evaluation, Beijing, China, October 2009

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Gonçalves, R., Trinca, A.J. & dos Santos Ferreira, G.C. Effect of coupling media on velocity and attenuation of ultrasonic waves in Brazilian wood. J Wood Sci 57, 282–287 (2011).

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Key words

  • Nondestructive testing
  • Nondestructive evaluation
  • Longitudinal waves
  • Transverse waves