Optical breakdown acoustics : transduction and sensing underwater

In the sea, infrastructures such as ships, pipelines, and wind turbines are exposed to harsh conditions that can wear down the structures through wave loading and corrosion. Because of these wear mechanisms, maritime structures require regular inspections to identify early signs of damage or fatigue. Currently, inspections are performed visually or with contact acoustic transducers, often by a human diver. However, these methods are slow and costly, and can be hindered by surface irregularities like biofouling. Therefore, new sensing techniques are needed to meet the rising demand for offshore infrastructure monitoring. In this thesis, I develop optical breakdown as an acoustic source for non-contact measurements of underwater structures. Optical breakdown occurs when a high-power laser is focused to a small spot, causing nonlinear interactions between the light and water. A compact plasma forms at the focus and expands explosively, radiating a loud, broadband pressure wave.

Name thesis:degree_name

Doctoral

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2019

Author dc:creator

• Athanassiadis, Athanasios G.

Advisor dc:contributor.advisor

• Douglas P. Hart.

• Mechanical Engineering.

Statement dc:rights

• MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1721.1/122069

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/122069