Date of Award

Spring 2023

Document Type

Open Access Thesis

Department

Computer Science and Engineering

First Advisor

Victor Giurgiutiu

Abstract

Piezoelectric materials, defined by their ability to display a charge across their surface in response to mechanical strain, are great for use in actuation and sensing applications. Actuation applications include acoustic devices, motors and vibration damping while sensing applications include pressure sensors, medical devices, energy harvesting and structural health monitoring (SHM). The use of piezoelectric actuation and sensing across the lifecycle of aerospace metals is currently an expanding field with use cases beginning with the manufacturing process and ending with SHM.

The research presented in this thesis had three goals: (i) to develop methods for implementation of piezoelectric actuation in the additive manufacturing (AM) process; (ii) investigation of a novel method of determining instrumentation quality of piezoelectric wafer active sensors (PWAS) used in SHM; (iii) investigation into the effects of defects in piezoelectric sensors and sensor bonding on the PWAS response. Chapter 1 presents a review of piezoelectric material properties and fundamental equations. Chapter 2 centers on a fixture for implementation and maximization of ultrasonic wave propagation through to the substrate in the AM process using a piezoelectric transducer. Three transducer implementations were analyzed based on their transmission of out of plane ultrasonic velocity and it was determined that a thin plate glued to the piezoelectric transducer surface provided the best results for implementation, with 100% transmission of velocity and energy. Chapter 3 discusses a novel method of determination of piezoelectric instrumentation quality as well as investigation into the effects of defects in piezoelectric sensors and their bond to the structure on the PWAS response. This method was able to confirm defect-less instrumentation when PWAS instrumentation is analyzed in pairs. It was found that defective instrumentation resulted in decreasing amplitude of received and transmitted signals as well as changes in the frequency spectrums of the signals. The techniques developed during this research have wide application in state-of-the-art research for AM and SHM.

Rights

© 2023, Connor Griffin

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