New 1-3 type piezoelectric composite material for kilohertz frequency range transducers

1-3 type composite materials have been successfully used in transducers for medical imaging and nondestructive evaluation, where the typical frequency is in the megahertz range. In this paper, the authors present a new 1-3 type composite design which has the longitudinal (thickness) resonant mode in the kilohertz frequency range. The new 1-3 type composite material is created by a laminating technique. A head mass and a tail mass are bonded to the ceramic rod. These laminated rods are aligned in a matrix and embedded in an epoxy, polymer or urethane resin. The laminated rod matrix not only retains the advantages of conventional 1-3 type piezocomposite material, but also can achieve better acoustic impedance coupling to water. A three-dimensional finite element algorithm developed by Huang is used to simulate the new 1-3 type composite material. The general theory is described briefly. Good agreement between the theory and experiment is obtained