title: Beam diffraction effects in sound transmission of a fluid-embedded viscoelastic plate at normal incidence.
abstract: The characteristics of a sound beam transmitted through a fluid-embedded viscoelastic plate at normal incidence can deviate significantly from those of a plane-wave. Phenomena such as frequency shift, signal amplification or reduction, and changed beam properties, are observed for resonance peaks associated with specific leaky Lamb modes. When interpreting measurements using plane-wave theory, such deviations will influence the measurement of material parameters and plate thickness. The finite-element-based models used in this study describe the signal chain from the electrical voltage excitation at the piezoelectric transducer terminals to the sound pressure propagated through the plate and fluid to the position at which it is measured by a hydrophone. The measured phenomena are described at a quantitative level.
authors.affiliation: Department of Physics and Technology, University of Bergen, P.O. Box 7803, N-5020 Bergen, Norway magne.aanes@uib.no.
authors.forename: Magne
authors.initials: M
authors.lastname: Aanes
authors.affiliation: Christian Michelsen Research AS, P.O. Box 6031, Postterminalen, N-5892 Bergen, Norway kjetil@cmr.no.
authors.forename: Kjetil Daae
authors.initials: KD
authors.lastname: Lohne
authors.affiliation: Department of Physics and Technology, University of Bergen, P.O. Box 7803, N-5020 Bergen, Norway per.lunde@uib.no, magne.vestrheim@uib.no.
authors.forename: Per
authors.initials: P
authors.lastname: Lunde
authors.affiliation: Department of Physics and Technology, University of Bergen, P.O. Box 7803, N-5020 Bergen, Norway per.lunde@uib.no, magne.vestrheim@uib.no.
authors.forename: Magne
authors.initials: M
authors.lastname: Vestrheim