Author

Bao Chi Ha

Date of Award

2020

Document Type

Thesis

Degree Name

Master of Science in Engineering (MSE)

Department

Mechanical and Aerospace Engineering

Committee Chair

Gang Wang

Committee Member

David Lineberry

Committee Member

Jason Mayeur

Subject(s)

Structural health monitoring, Lamb waves, Lead zirconate titanate

Abstract

Because of their electro-mechanical coupling property, Lead-Zirconate-Titanate (PZT) materials have been widely used for ultrasonic wave sensing and actuation in structural health monitoring applications. In this thesis, a PZT rosette sensor concept is proposed to conduct Lamb wave based damage detection in panel-like structures by exploring its best directional sensing capability. First, a directivity study was conducted to investigate sensing of flexural Lamb wave propagation using the d33 effect in a PZT fiber. Then, commercial off-the-shelf PZT fibers were polarized in-house in order to construct the PZT rosette in a rectangular configuration, in which three PZT fibers were oriented at 0, 45, 90 degrees, respectively. Since Lamb wave responses are directly related to measured PZT fiber voltage signals, a simple interrogation scheme was developed to calculate principal strain direction in order to locate acoustic source. Comprehensive tests were conducted to evaluate the performance of the proposed PZT rosette using an aluminum plate. It is shown that the PZT rosette is able to sense Lamb wave responses and accurately locate an acoustic source. In the future, the PZT rosette performance is going to be further evaluated with damages introduced to plate.

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