Term of Award

Summer 2024

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

Hossain Ahmed

Committee Member 1

Mohammad Ahad

Committee Member 2

Mosfequr Rahman

Non-Voting Committee Member

Riaz Ahmed

Abstract

This research project reports an exploratory investigation of energy harvesting effect on isotropic material that goes through low frequency mechanical fatigue. Energy harvesting is a growing field of study that can recycle ambient energy back into a system that would otherwise be lost. This is a significantly useful method for the ongoing energy crisis and provides an alternate route to design and upgrade systems to be more efficient and last longer than current system designs. However, it is time to investigate if there is any effect vibration-based energy harvesting has on the structure from which energy is being harvested. To answer this novel research question, both numerical and experimental studies are designed to determine the ultimate tensile strength and fatigue life of Aluminum structures with and without employing energy harvesting technique. Numerical studies are performed by commercial finite element solver and the experimental studies are performed by well controlled material testing systems. Two sets of specimens are prepared following ASTM standards. While the first set is reserved for baseline tests to determine ultimate tensile strengths and fatigue life without energy harvesting, the second set is used for inducing fatigue test with varying fatigue loads (3 Hz and 5 Hz). Energy is harvested from the second set of specimens. To quantify the material property degradations, linear ultrasonic wave velocity and non-linear normalized second harmonic frequencies are determined. Finally, the remaining strengths of the fatigued specimens are determined, and a correlation is drawn if energy harvesting has any effects on these mechanically fatigued specimens. A good match is found between the experimental and simulation results. The results show an average decrease in ultimate strength of 8% at 5Hz frequency and 13% at 3Hz frequency.

Research Data and Supplementary Material

Yes

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