John C. Cochran - Introduction to Sonar Transducer Design

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John C. Cochran

Raytheon Technologies, RI, USA (Retired)

This edition first published 2022 © 2022 John Wiley & Sons, Inc.

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I dedicate this book to those who have alwaysbeen there for me: my wife Elizabeth; my children Laura, Daniel, Sarah, and Rebecca; and my mom and dad. I love you all.

This text is the result of my efforts over the years to understand the broad subject of underwater electroacoustic transducer design. To fully understand underwater transducers, one must understand many different aspects of physics, electrical, and mechanical engineering. It is the broad nature of acoustic transduction that I enjoy very much.

I started working in the underwater transducer business in 1983. I joined a small company which specialized in the design and manufacture of underwater acoustic transducers. At the time, I had no idea what a transducer was. I quickly found that you had to be a jack‐of‐all‐trades in order to be successful at making transducers. The wide range of expertise required to fully understand underwater transducer design was very attractive to me. I was not one to be pigeonholed into any one particular area of engineering discipline. I embraced the opportunity to be what I consider a true engineer to be – an individual who employs the basic principles of physics and chemistry to solve practical problems and who can implement these solutions into a manufacturable product.

Unfortunately, the process of “coming up to speed” in transducer design is made very difficult by the lack of specific texts that address the subject. There are texts that address the mechanics of piezo‐electric materials and texts on acoustic theory, but there are very few texts that address the broad range of topics associated with underwater transducer design. As a result, I was constantly bombarded with “rules of thumb” that had their basis in sound physical principles but for which no one could account. Not being one to accept the “rules of thumb” on faith alone, I have endeavored to understand the basis for the theories that are applicable to underwater transducer design. It is these basic principles that I hope to document in this text.

I consider the text to be an introductory text in underwater acoustic transducer design. The text walks through the development of various theories starting from the first principles. In some cases, the mathematical development may lead someone to think that I should have jumped to the answer sooner. However, it is for the beginner in this field that I have written this book. The beginner should feel that he can follow mathematical development completely. I have put many of the intermediate mathematical steps into this text.

Though written for the beginner in this field, the text is also for the advanced student or practicing engineer. The mathematical development is fairly thorough and requires some experience with advanced mathematical functions (such as Bessel’s functions) in order to get the most out of it.