| Author: | Wen, Fuzhen |
| Title: | Shear-horizontal waves generation and reception using piezoelectric wafers for thin-plate structure damage detection |
| Advisors: | Cheng, Li (ME) |
| Degree: | M.Sc. |
| Year: | 2017 |
| Subject: | Hong Kong Polytechnic University -- Dissertations Shear waves Structural health monitoring |
| Department: | Department of Mechanical Engineering |
| Pages: | xiii, 93 pages : color illustrations |
| Language: | English |
| Abstract: | Structural health monitoring (SHM) techniques with shear horizontal (SH) waves have shown attractive advantages due to the non-dispersion feature of the fundamental SH0 mode wave. This work investigates the SH0 wave generation and reception using d35-mode shear horizontal piezoelectric wafer sensors (SH-PWAS). Finite Element (FE) and experimental results show that not only SH0 wave but also S0 mode and A0 mode of Lamb waves can be excited and received by SH-PWAS transducers, suggesting the necessity of considering the parameter-design of the SHM system to eliminate the Lamb-wave interference to the SH0 wave. Experiments are carried out to calibrate the group velocity, dispersion curves, the amplitude-frequency relationship, as well as the intensity attenuation of the guided waves in a 1.5-thick aluminum plate. An FE model is established with four SH-PWAS transducers serving as a sensor network for the detection of a 16mm-long and 0.3mm-wide non-thickness-through crack in the plate. It is observed that additional SH0 wave generated by the crack can be captured by one SH-PWAS sensor. The mode-conversion from SH0 wave to S0 and A0 waves can be detected by another SH-PWAS sensor, providing multiple diagnosis information for the damage detection. Following the configuration of the FE model, experiments are conducted using a baseline method based on the pristine and cracked results. A fairly good agreement is found among the FE simulations and experiments, thus confirming the practicability of the proposed sensor network. This work, as a whole, establishes the fact that SH0 wave can be effectively generated and captured using SH-PWAS sensors. The study also reveals various physical phenomena which provide useful guidelines for future SH0-based SHM technology in terms of both system design and SHM diagnosis. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 991021962224103411.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 6.39 MB | Adobe PDF | View/Open |
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