Theses and Dissertations

Date of Award


Document Type


Degree Name

Master of Science (MS)


Mechanical Engineering

First Advisor

Dr. Yingchen Yang

Second Advisor

Dr. Horacio Vasquez

Third Advisor

Dr. Dumitru Caruntu


Autonomous underwater vehicles' (AUVs) endurance is constrained by the lifetime of their batteries and the distance that tether wires can traverse. Solving the endurance problem of AUV using the enormous potential of ocean wave energy is the motivation behind this thesis. The objective of this research is to model a mass-spring-damper system to emulate the permanent magnet linear generator (PMLG) of a self-recharging AUV and identify its energy absorption capability through numerical simulation and experimental testing. The research activities started with modeling and fabricating a 1:5 scale model. The scaling was done by comparing the most common AUV size of 1.5m. The preliminary dry testing result confirmed the inadequate damping of the devised prototype. After detailed wave tank testing with a fixed PTO, the vertical orientation of the converter was chosen for the second stage research. A modified 1:3 large-scale prototype was developed in the next phase. The model showed strong oscillating mass motion in the dry test rig. Comparison with numerical simulation showed that for lower wave frequency, the damping coefficient of the model matches well with the experimental result. But the prototype damping behavior is much more complex for a higher wave frequency. The tank testing confirmed that the prototype pitch amplitude in the wave needs to be enhanced for higher energy absorption.


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