Hydrophones are electroacoustic aquatic transducers that convert mechanical energy from sound waves to electrical energy. Such sensors are used in applications such as in the study of marine biology, analysis and design of vessels, sonar systems, torpedoes and surveillance systems. The spherical hydrophone model consists of two hollow piezoceramic hemispheres coated internally and externally with electrodes. The operation is based on the generation of electrical signals in response to the mechanical vibrations of the sensor. The signal generated quality (amplitude and frequency response) is dependent on the geometric and dimensional characteristics of the piezoceramic layer. This master project aims to study the isostatic pressing of piezoceramic semispheres and the subsequent green machining, aiming to achieve uniform thickness, sphericity and homogeneity. For the project development finite elements simulations will be done to assist in optimized design of molds for isostatic pressing. The software ABAQUS will be used for the simulations using the Drucker-Prager / cap model for the ceramic powder and a hyperelastic model for the mold. For the finite element model implementation, mechanical tests are necessary to calibrate the parameters of the behavior of the ceramic powder, mold and the friction between both. Eventual geometric distortions will be compensated in subsequent green machining of the external surface of the hemispheres. For this purpose, a functional prototype of an abrasive machining apparatus will be constructed. The green machining will be optimized with respect to the cutting parameters and tool trajectory. The project is expected to develop a structured manufacturing methodology of piezoelectric semispheres that meet the requirements of high performance signal capture for a long life in service.
News published in Agência FAPESP Newsletter about the scholarship: