ASA 127th Meeting M.I.T. 1994 June 6-10

4aEA8. A perturbation method applied in a study of lamb wave sensors.

Zhemin Zhu

Jian Li

Inst. of Acoust., Nanjing Univ., Nanjing, People's Republic of China

Junru Wu

Univ. of Vermont, Burlington, VT 05405

There are basically two approaches in studies of sensing using Lamb wave sensors [J. Acoust. Soc. Am. 91, 861--867 (1992)]: the dispersion equation method and the acoustic impedance method. The first approach is exact but complicated; the latter is simple but approximate. In many Lamb wave sensing applications, changes of the boundary conditions to be detected can be considered to be small perturbations to the propagation of free Lamb wave in a thin plate. General dispersion equations for Lamb waves in a plate with proper perturbed boundary conditions are derived. The equations are then applied to various sensing applications including viscous mass loading. [Work of JWU supported by NSF and Vermont EPSCoR.]