OPTIMAL-DESIGN 1-3 COMPOSITE PIEZOELECTRICS

An optimal design problem for piezoelectric composite hydrophones is c onsidered. The hydrophone consists of parallel piezoelectric rods embe dded in a porous transversely isotropic polymer matrix. We find the sh ape, volume fraction, and spatial arrangement of the piezoceramic rods , and the structure of the matrix material that maximizes the hydropho ne performance characteristics. We found that the optimal composite co nsists of a hexagonal array of rods with small volume fraction, in a h ighly anisotropic matrix that is characterized by negative Poisson's r atios in certain directions. The performance characteristics of hydrop hones with such a matrix are significantly higher than those with an i sotropic polymer matrix. The results can be viewed as theoretical uppe r bounds on the hydrophone performance.