Journal or Book Title
Applied Physics Letters
A Lamb wave resonance has been found that allows unusually efﬁcient transmission of airborne sound waves through plates. This occurs at the zero-group-velocity point at the frequency minimum of the ﬁrst-order symmetric (S1 ) Lamb mode. At this frequency, plane waves with a range of incident angles can couple between the air and the Lamb mode in the solid plate, dominating the spectrum of transmitted focused sound beams by 10 dB or more. We use this frequency for C-scan imaging, and demonstrate the detection of both a 3.2-mm-diameter buried ﬂaw and a subwavelength thickness changes of .005l ~1%!.
Copyright 2003 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
American Institute of Physics
Holland, Stephen D. and Chimenti, Dale E., "Air-coupled acoustic imaging with zero-group-velocity Lamb modes" (2003). Aerospace Engineering Publications. 4.