Ultrasound Transmission Through Periodically Perforated Plates

Extraordinary acoustic reflection enhancement by acoustically transparent thin plates

“…In most of these studies, rigid plates were employed or assumed, hence it is the apertures, either individually or collectively, that account for the phenomena. With the elasticity of the solid plates fully taken into account, the acoustic transmission enhancement originated in the resonant excitation of the intrinsic Lamb waves [16,17] has been observed too.…”

“…High transmission of the reference plate also attributes to the fact that the wavelength considered here is much larger than the plate thickness, which also account for no FP resonant peaks observed in the spectra. To verify the extraordinary reflection, experimental measurement based on the ultrasonic transmission technique [16,17] has been performed. In the experiment, the sample is clamped with desired tilted angles and placed in between a couple of generating and receiving transducers with diameters of 25.4mm and central frequencies at 0.5MHz .…”

“…The resonant modes in a thin strip are essentially the standing wave modes of the Lamb waves in the plate extending over the strip breadth. For an infinite solid plate immersed in liquid, there are rich numbers of intrinsic modes associated with the plate [16][17][18]20], generally classified as the symmetric and antisymmetric types.…”

Control of the stop band of an acoustic double fishnet

“…Studies of the acoustic response of such perforated solid bodies have shown that at certain frequencies, dictated by the slit (or hole) depth there may be near unity transmission of sound. [1][2][3] Another study 4 has shown that perforated plates may suppress the transmission of sound better than an entirely solid plate of real (i.e., not perfectly rigid) material across a narrow frequency band owing to diffraction effects. More recently, the response of two non-diffracting solid perforated plates separated by a small gap has been explored.…”