Term of Award

Summer 2021

Degree Name

Master of Science, Mechanical Engineering

Document Type and Release Option

Thesis (open access)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Department

Department of Mechanical Engineering

Committee Chair

Jinki Kim

Committee Member 1

Ermias Koricho

Committee Member 2

Jung Choi

Abstract

In recent years, lightweight structures have become mature and adopted in various applications. The importance of quality assurance cannot be overemphasized hence extensive research has been conducted to assess the quality of lightweight structures. This study investigates a novel process that exploits motion magnification to investigate the damage characteristics of lightweight mission-critical parts. The goal is to assure the structural integrity of 3D printed structures and composite structures by determining the inherent defects present in the part by exploiting their vibration characteristics. The minuscule vibration of the structure was recorded with the aid of a high-speed digital camera, and the motion was estimated by applying a phase-based algorithm. The spectral information was compared with the results obtained by a laser displacement sensor for validation. Then, the video-based results were used to perform damage identification by comparing the extracted information with that of a baseline. The resonance frequencies and the corresponding operational mode shapes of the test structure was obtained using the motion magnification algorithm by applying a bandpass filter around selected resonant frequencies. The resonance frequency and operational mode shape are quantified to compare the damaged structure with the baseline. The damage characteristics depending on the location and depth of damages were experimentally explored and numerically analyzed. Overall, this study provides an accurate, easily available and fast approach in structural health monitoring, utilizing video-based vibration analysis. It is envisioned that this study will provide a foundation for both commercial and non-commercial purposes exploiting the straightforward and low-cost implementation of video-based method.

Research Data and Supplementary Material

Yes

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