Properties of attenuating ultrasonic waves
This is a joint project with Dr Marc Deschamps at the University of Bordeaux. The theory of guided wave propagation in plates is well understood for structures in which there is no significant energy loss, such as Lamb waves in a free metal plate. However, there are circumstances when the energy of the waves may decay rather rapidly. These include leaky waves, when a plate is immersed in a fluid or embedded in another solid, and damped waves, when materials such as plastics have strong energy-absorbing characteristics. Theoretical models have been developed for these cases and are mostly satisfactory, but there are some aspects which are poorly understood. This project aims to improve the understanding of the decay phenomena. This understanding will be very valuable for the development of inspection techniques for such structures.
Simonetti, F. and Cawley, P. 'A guided wave technique for the characterization of highly attenuative viscoelastic materials', J Acoust Soc Am, Vol 114, pp158-165, 2003.
Simonetti, F. and Cawley, P. 'Ultrasonic interferometry for the measurement of shear velocity and attenuation in viscoelastic solids', J Acoust Soc Am, Vol 115, pp157-164, 2004.
Simonetti, F. and Cawley, P. 'On the nature of shear horizontal wave propagation in elastic plates coated with viscoelastic materials', Proc Royal Soc Lond: Mathematical, Physical and Engineering Sciences, Vol 460, pp2197-2221, 2004.
Simonetti, F., Cawley, P. and Demcenko, A. 'On the measurement of the Young's modulus of small samples by acoustic interferometry', Journal of the Acoustical Society of America, Vol: 118, pp832-840, 2005.
A Bernard, M Deschamps M J S Lowe, "Comparison between the dispersion curves calculated in complex frequency and the minima of the reflection coefficients for an embedded layer ", J.Acoust. Soc. Am., vol. 107, pp. 793-800, 2000.
F Simonetti, M Lowe, "On the meaning of Lamb mode non-propagating branches", J.Acoust. Soc. Am, vol. 118, 186-192, 2005.