Finite-element electroacoustic analysis and Taguchi design of piezoelectric buzzers based on the vibration absorber model

Lumped parameter models of piezoelectric buzzers are established with finite element-based electroacoustic parameter identification procedures. The analysis starts with modeling the diaphragm structure by using finite element method (FEM). The FEM model is then converted into electro-mechanical two-ports to fit into the electro-mechano-acoustical (EMA) analogous circuit. Electrical impedance of the piezoelectric diaphragm is simulated using the model. An ‘added-mass’ method is developed to identify the lumped parameters. Electrical impedance and on-axis sound pressure level (SPL) of a piezoelectric buzzer (containing the diaphragm and case) can be simulated by solving the loop equations of the analogous circuits. On the basis of the model, optimal structural parameters and configurations for the buzzer can be found to maximize the sound pressure output, using the Taguchi method and constrained optimization. Simulation and experimental results showed that the performance has been significantly improved using the optimal design. Design guidelines for the piezoelectric buzzers are summarized.