Ultrasonic characterization of solid materials

Abstract

This research project aims to develop ultrasound measurement techniques for the characterization of solid materials (both piezoelectric and non-piezoelectric). Learning the properties of such materials is important for modeling ultrasonic transducers, which have been under investigation by the Laboratory of Ultrasound at the School of Engineering at University of Sao Paulo. In addition, accurate measurement of anisotropic material properties is strongly applied in aerospace and naval industries. New methodologies will be developed to determine the complex properties of piezoelectric ceramics with circular and annular geometries. The variation with temperature of piezoelectric, dielectric and elastic properties of piezoelectric materials will also be studied. Regarding the characterization of non-piezoelectric materials, techniques and experimental setups will be implemented to allow the measurement of elastic constants of isotropic materials (metals, plastics and polymers) and anisotropic materials (fiber glass / carbon) with a better temperature control. After characterizing the materials that compose the transducer, simulation of the models (piezoelectric ceramic, ceramic glued on the plate/disc, ultrasonic transducers) will be carried out. For validating the determination of non-piezoelectric and piezoelectric properties, the theoretical results (finite element method - 2D and 3D) of the vibration of piezoelectric ceramics, piezoelectric transducers and the propagation of elastic waves in plates and metal discs will be compared to the experimental results (interferometer, electrical impedance). (AU)