Study of the homogeneity of isostatic pressing of piezoceramic hyperspherical caps and planning of external green machining

• Grant number: 18/07928-2
• Support Opportunities: Scholarships in Brazil - Master
• Start date: September 01, 2018
• End date: February 29, 2020
• Field of knowledge: Engineering - Mechanical Engineering - Manufacturing Processes
• Agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Carlos Alberto Fortulan
• Grantee: Mateus Mota Morais
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

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.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

MORAIS, MATEUS MOTA; DE MELO, CAIUA CALDEIRA; CANTO, RODRIGO BRESCIANI; FORTULAN, CARLOS ALBERTO. Calibration of powder constitutive model using digital image correlation validated for hollow hemisphere of lead zirconate titanate. Powder Technology, v. 392, p. 212-223, NOV 2021. (18/02801-4, 18/07928-2)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

MORAIS, Mateus Mota. Design and manufacture of piezoceramic semi-spherical caps for hydrophone applications. 2020. Master's Dissertation - Universidade de São Paulo (USP). Escola de Engenharia de São Carlos (EESC/SBD) São Carlos.