Computational and experimental investigation of the fields generated by a 1-3 piezocomposite transducer

Large-scale three-dimensional numerical simulations using the finite-differ ence time domain technique are used to compute the continuous wave fields a ssociated with a composite transducer. The interior of the transducer is ma de of a periodic array of square rods. This lattice causes elastic wave Bra gg diffraction similar to electrons in a periodic lattice, A low frequency mode shape is assumed for the rods. This prescribed motion includes longitu dinal and transverse components. It is shown that the transverse motion in the rod gives rise to shear waves causing standing waves (lateral resonance s) in the polymer regions. This is also confirmed by experimental results p resented here and other independent analytical and experimental work. The f ull-scale numerical simulation is performed on a large parallel supercomput er and permits modeling of not only the composite transducer but the radiat ed pressure from near to far field. In addition, cover plates and edge effe cts are included, unlike analytical treatments. Although only mechanical ef fects are included, the wave propagation approach captures many essential f eatures. (C) 2001 Elsevier Science B.V. All rights reserved.