Mechanical Engineering ETDs

Publication Date

Fall 12-15-2024

Abstract

Piezoelectric micro ultrasound transducers (PMUT array) are pivotal in MEMS applications. They typically operate in the fundamental (0,1) acoustic mode and are not significantly researched for higher modes (0,2) and (0,3). Similarly, vibrating mesh atomizers (VMAs) demand the second (0,2) mode and third mode (0,3) for effective aerosol generation, highlighting the need for optimized electrode configurations—a relatively unexplored area. This study presents the first comprehensive analysis of how electrode designs influence PMUT performance in the (0,2) mode for VMA applications.

Utilizing COMSOL multiphysics finite element modeling (FEM) with residual stress considerations alongside experimental validation, we demonstrate that optimized electrode configurations can enhance PMUT displacement and velocity by up to 4.7 times compared to conventional electrode designs. Among the seven configurations experimentally tested, multiple-ring electrode model 6 aligned with stress nodal circles achieved the highest performance during single-phase actuation, delivering 4.1 times greater actuation than the center-only electrode model 1 design. These enhancements improve membrane dynamics, enabling resonance frequencies that are ideal for efficient atomization.

Our findings significantly advance Vibrating Mesh Atomizer (VMA) technology by enabling more precise and reliable aerosol generation for medical drug delivery and ultrasound imaging applications. Additionally, the optimized electrode strategies offer potential improvements for higher-order PMUT array modes in ultrasound imaging, providing better axial resolution. This pioneering work underscores the critical role of electrode configuration in optimizing PMUT functionality, paving the way for advanced MEMS device applications and improved performance in various technological fields.

Keywords

Piezoelectric Micromachined Ultrasonic Transducer (PMUT), Eigen-Frequency Analysis, Mode (0, 2), Frequency Domain Analysis, Stress Nodal Circles, Nodal Diameters, Vibrating Mesh Atomizer (VMA), PZT (52/48), Con- tact Poling, Interferometer, Electrode Optimization, Finite Element Method, Micro- electromechanical Systems (MEMS), Single Phase Actuation, Dual Phase Actuation

Degree Name

Manufacturing Engineering

Level of Degree

Masters

Department Name

Mechanical Engineering

First Committee Member (Chair)

Nathan Jackson

Second Committee Member

Matthias Pleil

Third Committee Member

Heng Zuo

Document Type

Thesis

Language

English

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