About Me


Biography

I am:

a consultant in vibration and acoustics, flow induced vibration, and noise control

a Retired Professor in the Penn State Graduate Program in Acoustics

Former Director of Penn State's Center for Acoustics and Vibration (CAV)


Education

D.Sc. Mechanical Engineering, 1996, the George Washington University,
Thesis topic: Formulations and Methods for Robust and Efficient Optimization of Acoustic Radiated Noise Problems

M.S. Mechanical Engineering, 1987, Virginia Tech,
Thesis topic: Structural Shape Optimization of 3D Finite Element Models

B.S. Mechanical Engineering, 1986, Virginia Tech.



Professional Affiliations

Fellow, Institute for Noise Control Engineering (INCE)

Fellow, American Society of Mechanical Engineering (ASME), Member and past President of ASME Noise Control and Acoustics Division

Vice President of Rules and Governance, International INCE

International Organizing Committee for the NOVEM (Noise and Vibration EMerging Methods) and FLINOVIA (FLow Induced NOise and Vibration Issues and Aspects) conference series.

For more details download my full resume

Consulting

I serve as a subject matter expert for US government agencies and commercial companies, as well as an expert witness in litigation cases. Contact me for my rates. The first phone or web consultation is always free.

MODELING METHODS

I provide guidance on accurate and cost-effective ways to model vibration and sound in complex structures and systems, as well as mechanically and flow-induced forcing functions.

I am an expert in finite element analysis (FEA) for structural vibrations and sound in enclosed spaces, boundary element analysis (BEA) for exterior sound, and statistical energy analysis (SEA) and hybrid SEA-FE methods for mid- to high-frequency vibroacoustic analysis.

I also perform vibration-induced structural fatigue assessments for metals and composites and consult on nonlinear vibration phenomena, such as shock and earthquake induced vibration on large structures and buildings.

MEASUREMENTS

I evaluate measured:

vibrations (modal analysis and vibrations during operation),

sound pressures (in air or in water),

flow-induced wall pressure distributions for low and high-speed flows (including transonic).

I also provide guidance on measurement plans and instrumentation for upcoming tests, including multi-sensor signal processing analysis.

EXPERT WITNESS

I provide expert reports and testimony on acoustics and vibration issues including:

compliance with measurement standards, noise ordinances, and health requirements;

patent and intellectual property infringement disputes;

remediation planning.

Teaching and Training


INCE-USA Noise Control Course - Advanced

I teach the third and final online Advanced course in Noise Control for INCE-USA Students who successfully complete the course may apply for INCE board certification without taking the Board exam.

Topics include:

- Sources of noise (machinery and turbomachinery)

- Outdoor noise and structural acoustics

- Advanced measurement and analysis (spectral analysis, modal analysis)

- Noise and vibration treatments (Mounts, enclosures, damping, mufflers, active control)

- Numerical methods (finite elements, boundary elements, statistical energy analysis)


Short Courses

UPCOMING
I will be giving a one day short course on Fundamentals of Vibration and Sound on Sunday, 9 June 2024, before the 2024 Noise-Con in New Orleans, Louisiana. I will add the registration link here when it's available.

CUSTOM
I also assemble and teach customized short courses both on-site and online for US government agencies and commercial companies.

Course lengths vary from a single day to three days, and cover topics in vibration, acoustics, noise control, flow-induced forces (turbulent flows, instabilities, tonal noise), modeling methods, and measurement methods.

I usually include customized course material for individual clients based on their target applications.

Contact me to discuss your interests - I'll put together a proposed customized course at no obligation.


Online Demonstrators

Interact with sound and vibration online!

I have developed a series of javascript-based online interactive demonstrators of acoustics and vibration behavior for my short course participants and customers.

Use sliders and dropdown menus to change properties and watch sound fields, vibration patterns, and responses like mobilities and radiated sound power change.

Animate pressure waves and structural modes. You can also learn about signal processing by creating your own waveforms and generating frequency spectra using different processing parameters.

I add new demonstrators often so check back for updates.

Research

Some brief examples of my research interests are shown below. See my publications and resume for more details.

Structural Vibration

A flat plate mode of vibration. Here, the edge boundaries are simply supported, with two half waves spanning each plate direction.

I have performed many experimental and computational modal analyses on complex structures. The modes are the fundamental basis of forced vibration and sound analyses.

Sound Radiation

A plate mode of vibration (bottom) radiates a spatially varying sound field. I teach vibration and radiated sound theory in INCE-USA's Advanced Noise Control Engineering course.

I have also investigated many computational and experimental ways to model and measure radiated sound.

Flow Induced Noise and Vibration

Wall pressures induced by turbulent shear flow from an upstream nozzle wash over a plate. These pulsations can be strong enough to cause structural fatigue cracking and failure.

I have also investigated flow induced vibration and noise caused by turbulent boundary layers, ingested turbulence, and jets.

Noise Control

A sound wave on the left strikes a noise barrier, which vibrates and radiates a weaker sound wave to the right. You can learn more about this problem in the sound transmission loss tutorial below.

I have also designed noise control treatments like viscoelastomers for structural damping, composite sound barriers, particle impact dampers; and developed methods to optimize structural shapes and treatments for reduced vibration and sound radiation.

Here is a video recorded by International INCE (Institute for Noise Control Engineering) of my talk on Flow Induced Noise and Vibration at the 2017 Hong Kong Internoise. After some preliminaries about the 2017 Flinovia II Symposium held at Penn State in May 2017 is my attempt to summarize this field, drawing from work by symposium authors. Here is the paper that accompanies this talk. A proceedings book on FLINOVIA II has been published by Springer - see the link in the Publications section below.

I gave a plenary at the Madrid 2019 Internoise on infinite structure mobility theory - one of the most useful tools a vibroacoustician has. It wasn't recorded, but I gave the same talk to our Center for Acoustics and Vibration (CAV) at Penn State - here's the video. The accompanying paper is in the section below.

The internet is full of freely available fantastic vibroacoustic resources, if you know where to look. Here is my talk to our Center for Acoustics and Vibration (CAV) at Penn State on this topic. The accompanying paper is in the section below.

I was honored to present the Rayleigh Lecture at the ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE). I gave a tutorial on vibroacoustics based on the material in my book (see below). You can watch the lecture on the ASME site but you will need to enter your name and contact info first (you can opt out of any ASME communications though).

ASME_IMECE

Publications

Below are links to my books and tutorials. You can find the rest of my journal and conference publications on my Google Citations page.

Engineering Vibroacoustics

I co-edited/co-wrote this book, published as part of Wiley's Book Series on Acoustics, with Don Nefske and Sue Sung. The book includes 15 chapters ranging from the basics of structural vibration and radiated sound to numerical methods and noise control treatments. You can buy it from Wiley

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1st Flinovia Proceedings

My colleagues from Italy and France and I organized the first Symposium on Flow Induced Noise Issues and Aspects in Rome, Italy in November 2013. The book includes 15 papers by world-renowned experts in this field, available on Amazon. You can also buy and download individual chapters at the Springer website.

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2nd Flinovia Proceedings

We held the second Symposium on Flow Induced Noise Issues and Aspects at Penn State in April 2017. The 2nd edition includes 22 papers, available on Amazon. You can also buy and download individual chapters at the Springer website, including my paper on panel vibration induced by transonic turbulent flow.

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3rd Flinovia Proceedings

We held the third Symposium on Flow Induced Noise Issues and Aspects at INSA de Lyon, France in September 2019. The 3rd edition includes 18 papers, available on Amazon. You can also buy and download individual chapters at the Springer website, including my paper on plate vibration induced by low speed turbulent boundary flow.

Structural-Acoustics Tutorial Part 1

I wrote my first tutorial on structural acoustics for Acoustics Today, at the request of founding editor Dick Stern. It covers the basics of waves in structures, modes of vibration, mobility and impedance, infinite structure theory, structural damping, and finite element analysis.

Structural-Acoustics Tutorial Part 2

I collaborated on the second Structural Acoustics Tutorial with my Penn State colleague, Dr. John Fahnline, well known acoustic boundary element expert. We explain the basics of sound radiation, radiation efficiency and damping, sound transmission loss, and boundary element analysis.


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Tutorial on Sound Transmission Loss Simulations

This tutorial expands on sound transmission loss simulations.

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Tutorial on Vibroacoustics of Composite Sandwich Panels

This tutorial draws from my group's work on quieting composite sandwich panels, covering bending wavespeeds, structural modes of vibration, mobility, damping, and radiation efficiency.

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Tutorial on Wavenumber Transforms of Vibrations

I have found that students have difficulty understanding wavenumber transformations. This tutorial includes some animations and discussion to demystify this concept.

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Tutorial on Infinite Structure Mobility

Infinite structure mobility theory is one of the most useful tools a vibro-acoustician has. You can Q/A mobility measurements, estimate high frequency vibration response, and predict the effects of structural material changes.

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Fantastic Vibroacoustic Resources and Where to Find Them

The internet is full of fantastic vibroacoustic resources. In this paper I provide descriptions and links to teaching websites, reports, articles, and software that any vibroacoustician would find useful.

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Tutorial on acoustic fluid loading of structures

Acoustic fluid loading can influence structural vibration dramatically. Learn about the fluid loading effects of exterior air and water, as well as enclosed air cavities.


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Tutorial on the vibrations of cylindrical shells

This tutorial tries to explain the complex topic of cylindrical shells without excessive mathematics, using several measured examples to explain the concepts of ring frequency, infinite shell theory, and helical wavenumbers of modes of vibration.

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Modal based experimental vibro-acoustic analysis of sandwich panels

We measured the modes of vibrations of a composite sandwich panel with stiffened ends and used the modal information to also calculate energies, conductances, and radiation damping.

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Wavenumber analysis of panel vibrations induced by supersonic wall-bounded jet flow

We compared the wavenumber content of panel vibrations and multiple surface pressure distributions from different wall-bounded jet flows, showing that strong matching of excitation and mode shape at the same wavenumbers leads to strong vibration response.

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Variability in measured resonance frequencies and loss factors of a bolted panel structure

My PhD student, Dr. Jerome, measured resonance frequencies and damping loss factors for two bolted panels that were assembled and disassembled repeatedly. The results show quite a bit of variability.

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NASA Report on Rotorcraft transmission noise path modeling

Most rotorcraft transmissions use rolling element bearings, which can be quite noisy. We modeled and measured vibration transmission through a gearbox equiped with rolling element and journal bearings to investigate the differences.

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NASA Report on Acoustically Tailored Conposite Rotorcraft Panels

We designed, built, and tested two prototypic rotorcraft roof panels with Bell Helicopter: one using Aluminum-based sandwich panels, and the other using two composite sandwich panels separated by a gap filled with absorbent material.

contact me

Interested in my consulting services or arranging for a customized short course for you or your group? Please contact me using the coordinates below.

contact information