Response Dynamics Logo
Since 1984 - Now in Our 32ndYear
Contact Us:
Reuben Hale, P.E.
Ph: (510) 507-1300


High Tech Consulting

Heavy Industry Consulting

Facility Design Consulting

Product Vibration & Noise

Emergency Solutions

Vibration Consulting

Acoustic Consulting

Vibration & Noise Monitoring

Construction Monitoring

Site Testing & Analysis

Diagnostic Testing

Sensitivity Testing

Vibration & Noise Isolation

Modal & Resonance Testing

Finite Element Modeling

Shake Table Testing

Strain Gauge Testing

Servo Control Consulting

Thermal Testing & Design

Magnetic Field / EMF / EMI

About Us / Partial Client List

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Reuben at Gemini South
Home : Overview

Response Dynamics Vibration Engineering, Inc provides unmatched consulting expertise in advanced vibration analysis, diagnostic testing, and engineering design. We combine our engineering test and analysis expertise in areas relating to vibration, motion control, acoustics, thermal, strain, flow, and magnetic field, with over 30 years of system troubleshooting and design consulting experience. We love to educate people on our work and the principles and concepts behind what we do. Feel free to call us with any questions that may relate to a your system or facility problems. The following is a brief summary of our areas of expertise and our approach.

Industries and Projects Spanning 9 Orders of Magnitude

5 images showing our range of vibration testing and vibration analysis services, first is of people in bunny suits in a semiconductor cleanroom, second is of a scanning electron microscope image disturbance, third is of a telescope structure on which we performed vibration testing, fourth is of laser optics and accelerometers from modal testing we performed, fifth is of an ocean going oil drilling rig similar  we have performed acoustic testing and analysis.

As vibration consultants we work on all kinds of interesting systems to characterize the vibration symptoms, test and make visible the structural dynamics responsible, identify sources, disturbance paths, and how coupling of sources with the structural dynamics manifest the problem issue at hand.

As acoustic consultants we often start with an acoustic characterization then put on our vibration consultant hats and show where, how and why the disturbing structures are vibrating to produce the acoustic disturbances. We then often test the acoustic parameters of absorption and reverberation and explain why the acoustic source is producing the noise levels it does given the frequency content of the disturbance and the enclosure geometry.

As magnetic field consultants we characterize fields mainly below the RF bands, 20 kHz and below, down to the very low frequencies to what might be called "DC fluctuations". Much of our work in magnetic field testing, analysis, and design has been on scanning electron microscopes (SEMs) and MRI equipment. SEMs are some of the highest resolution imaging tools and are sensitive to vibration, acoustics, and magnetic field disturbances.

We have engineered solutions for a myriad of systems, from sub-nanometer level disturbances of scanning electron microscopes, interferometers, and atomic force microscopes, to micron level motions of giant mountain top telescopes, to centimeter operating deflection shape analysis of offshore oil rigs, to name a few. (See our Client list by industry).

We have worked on hundreds of systems and facilities for High Tech Industries that include:

We offer engineering consulting services to numerous companies in the development of wafer fabrication and metrology equipment, biotech test and imaging systems, and other sensitive devices. Our extensive experience with micro-vibration and acoustic issues in the structural dynamics of sensitive high-resolution manufacturing, testing and imaging systems, makes us leaders in the field of sub-micron and nanometer scale technology. We work nationally, and worldwide, to improve performance, solve imaging, measurement, and vibration/acoustic design issues.

In Heavy Industry Consulting, we have worked on hundreds of systems and projects that include:

Five images associated with heavy industry vibration testing, first is of a power plant where we performed vibration monitoring, thermal analysis, strain gage testing, as well as dynamic testing, second is our vibration consultant in the power plant monitoring strain and acceleration signals, third is of the 120 megawatt steam turbine, fourth is of a large windmill were we performed vibration monitoring on an oil filter mount at the top of the tower, fifth is of dynamic testing on a large solar array using an 80 lbs electro-magnetic shaker supported on a fork lift to excite the structural modes of the solar array.

We characterize complex (often multi variable) problems, to design tests to diagnose the root cause of the issue, and to provide engineered solutions (See Manufacturing and Plant Process).

Diagnostic Testing

Response Dynamics has made Diagnostic Testing our bread and butter for over 30 years. We do this work well because we enjoy, and are well grounded in basic applied physics, digital signal processing, with advanced expertise in structural dynamics and how it relates to vibration and acoustic noise issues on a myriad of levels.

We are expert in resonance testing, Modal Analysis, Operating Defection Shape Testing (ODS), steady state and transient analysis, with literally decades of experience developing our detailed methodologies that produce meaningful results.

Fundamental to Dynamic Testing are Frequency Response Functions (FRFs). We design tests and/or analyse frequency response functions (FRFs) almost on a daily basis. These FRF measurements form the basis of modal analysis and the theory of linear structural dynamics. We are fluent in spectral analysis and the digital signal processing inherent in the measurement process and thus we can spot problems before they corrupt a whole data set, or an entire project.

A set of four images, first is of amplifiers and electronic signal filters used in dynamic testing, vibration analysis and control system testing, second is an image of our various sizes of force hammers ranging from and few grams to a couple of kilograms in weight, third are some of our electro-magnetic shakers, forth is of a triaxial accelerometer on an optical stage.

Non-linearities exist in all physical structures and are often not a problem. However when they are involved, we know how to spot them and deal with these unique dynamics. While testing, the choice to use electro-magnetic shakers, force hammers, or known inertial loads as force inputs depends on the nature of the system dynamics, the response amplitudes, and the transient/steady state characteristics of the vibration issue. We have refined these skills for over 30 years.

The physical principles of structural dynamics, optics, thermodynamics, and acoustics apply to structures and systems large and small. The variety of our projects keeps our work interesting, after all these years, even as we apply the same fundamentals again and again.

Meaningful Test Data, Knowing Good Data From Bad

We use our testing expertise, as well as various methods of analytic, computer modeling and Finite Element Analysis (FEA) to make sense of the system problems so that we will have confidence that our understanding is indeed correct (or sufficiently correct).

Frequency domain strain testing from a vibration analysis showing the spectra of 8 strain measurements on a new fan blade prototype, the resonance of the fan blade is prominent, as well as the harmonics of the spinning speed and 60 cycle line noise.. Colorful Finite Element Analysis, FEA, image of expected strain at the fan operating speed

We also make an effort to know what we don't know by considering measurement error, instrumentation noise, resolution limitations, and non-linear behaviors. See our discussion on Product R&D

The nuts and bolts of knowing good data from bad
brings indispensable value to our analyses

Experimental Design: The Most Important Step

We know from experience that the initial assessment is critical to asking the right questions at the start of investigation. These questions will lead to a set of initial hypotheses about the issues at hand. A sound foundation of basic physics, strong mechanical intuition, and years of structural dynamics experience are necessary to design an effective set of tests. The limitations of where instrumentation can be placed, the inherent sensor limitations, and the impact on the system dynamics need to be considered. Thus, designing the experimental setup to extract meaningful results is perhaps the most important step in solving a pressing issue where time, patience, and resources are in short supply.

We most often characterize a problem first and work from known conditions, and stay in “the known” as we proceed by making sense of what we observe as we move forward. This is very important. We test and analyze the change in dynamics we are trying to create in real-time, on site, and often make changes to our experimental test plan on the fly as we discover how a system is actually behaving. In doing so we often get meaningful results from which we can make sound engineering decisions in a short time frame. We do NOT make measurements and spit out data.

We focus on the important dynamic parameters of the system and its boundary conditions, and design tests to prove or disprove hypotheses. There are countless ways to create erroneous results. It takes effort and experience to extract meaningful results, interpret them, and then engineer creative and sound solutions. Whether it involves testing in the cleanroom instrumenting a delicate optical interferometer using a tiny non-contact capacitive sensor, or climbing through a power plant structure running hundreds of feet of cable to an accelerometer array to trouble-shoot a Turbine Isolation Issue, we employ many of the same principles, concepts, and methodologies.

120 Megawatt steam turbine, concrete turbine pedestal, and steel building structure, the large difference in thermal time constants between the steel building surrounding the pedestal and the concrete pedestal were involved in creating a vibration isolation problem.highly sensitive sub-nanometer capacitive sensor measurement between the edge of a semiconductor wafer and the tool's optics plate.

We are well versed in instrumentation, digital signal processing, and spectral analysis. We use our specialized skill set, and a vast selection of instrumentation that we have collected for over 3 decades, to design tests and solve tricky problems.

Multi-Variable Testing

Multi-variable testing is usually necessary to really get a handle on an issue involving multiple disciplines of physics. We design tests to measure static and dynamic strain, static and dynamic pressure, acceleration, velocity, displacement, magnetic field, temperature, fluid flow, and light intensity, to name a few.

Real world problems involving the measurement of multiple variables require an understanding of the physics of the coupling between them, as well as the physics and limitations of the measurement instrumentation. Problems in different frequency ranges necessitate unique approaches involving instrument selection, mounting dynamics, cabling, and coupling with other structures and media.

Graph of multi-variable testing and vibration monitoring used in vibration analysis showing multiple parameters., Plot showing the frequency response functions, the ambient acoustic noise spectrum, the floor vibration spectrum, and the bottom line spectrum of the semiconductor tool response, which show how the peaks in the frequency response function dictate the peaks tool disturbance response to the environment.

For instance, when a consumer product is too noisy, a bedside medical device for example, thermal analysis and optimization of the cooling system will often be part of the acoustic solution, in addition to surface damping treatments, motor vibration isolation, etc. In debugging scanning electron microscopes (SEMs) issues, disturbances due to acoustic excitation, floor vibration, control instability, frame resonances, thermal drift, and magnetic field all superimpose to create a confounding image disturbance. Additionally, each of these disturbances can be aliased. We have years of experience untangling overlapping disturbances involving multiple sources to make the issue understandable, and allow for educated decisions when weighing different solution strategies.


We very often get our hands dirty and build proof-of-concept “fixes” on site, or back in our shop, to quickly test a “design-fix” concept. We do this prototype testing carefully, with 30 years of structural dynamics experience, always working hard to test and keep an accurate understanding of the current system dynamics and the boundary conditions as we make changes.

Graph showing the vibration testing results of the frequency response of a delicate structure with and without a tuned mass damper, TMD, attached.

However, as so often happens to our clients, when quick and dirty fixes are attempted by other engineers with little structural dynamics experience, confusion, delay, and uncertainty regarding the design of the experiment often result. A faulty test often leads to the wrong conclusion and drives the wrong action. Valuable development time is often wasted, and the issue soon becomes an emergency. See our discussion on Product and Facility Emergencies.

We have the experience to quickly analyze past test methodologies and explain for the team what has been done well, and what needs improving, tweaking, or additional attention to a particular dynamic parameter. This is important for getting an engineering team all on the same page by making sure everyone understands the problem, what has been done, and how to move forward. These unique abilities have brought us long lasting working relationships with our clients.

Starting From Scratch, The Design Phase, Facility and Product Development

We enjoy being part of the team in the design phase. We help get the design right from the 1st alpha system to avoid last minute emergencies. We have recently worked in the design phase on a table top scanning electron microscope, a table top genomics ID system, and worked though the design and test of a cutting edge bio-tech imaging system with 25 nm resolution that will perform on upper floors of light construction. We have quieted noisy dialysis machines, eye surgery equipment, surgical robots, semiconductor imaging tools, and multi-ton solar tracking arrays.

We also work with architects and engineering groups on Facility Design for unique acoustics and vibration needs. These include state of the art semiconductor research facilities, university research buildings, tech-group collaborative office spaces, and others.

Plan view of a semiconductor facility used during vibration testing and vibration monitoringA gif animation of a modal analysis of a operating room floor system in a new hospital, showing the first diaphragm mode of the floor, with color contours.

Considerations that require our expertise include HVAC sourcing and distribution design, mechanical room design, equipment mounting, sensitive tool placement, floor system design, wall and partition design, sound masking, active cancellation, passive acoustics (added reverberation, or added sound absorption in particular frequency bands).

Plot of acoustic analysis results showing a comparison of acoustic noise levels with NC noise criteria.

For High Tech Facilities (such as: Semiconductor, Biotechnology, Pharmaceutical and Nanotechnology facilities), we not only have the expertise in the testing the building floor dynamics, vibration, and acoustics, but we understand the needs of the high resolution sensitive equipment used in these facilities because we design, fix, and test this equipment. We perform the Sensitivity Testing and write the specifications for some of the high resolution imaging and testing systems used in these industries. Additionally, we have spent decades troubleshooting facility issues and thus we have intimate knowledge of what issues to expect and how to prevent them. We translate that knowledge into design specifications and work with the design team on these critical design details.

Plot of vibraiton sensitivity modeling and comparison with experimental data common to much of our work a vibration consultant and acoustic consultant.

Some of the clients we have worked with over the years now manage engineering groups. It is these past clients that most often call us in the design phase of the product where we provide very valuable input in design reviews helping to show where potential pits falls may found, and where great improvement may be had by the adjustment of a few engineering details. Our input in the design phase will save valuable development time and resources, and has proven to be key to the success of many product efforts.

In product development, we provide assistance at several points along the product development cycle. Firstly, we provide assistance and guidance in the development of the conceptual and detailed design (often using a combination of analytic, numerical, and Finite Element Modeling). Our experience allows us to see potential pitfalls and find winning solutions, as part of your team, in the start of the design process. This is critical to staying on budget, on schedule, and meeting performance goals.

Once the prototype has been built, we perform measurement and analysis of the dynamic response of these systems to expected disturbances, including both internal sources (such as X-Y stage stopping transients) and external sources (such as floor vibration and acoustics noise). In addition, determination of system resonances by Modal Testing and analysis often provides critical design information. If necessary, the design is then improved by making appropriate changes in structural design, Stage Control, Vibration Isolation, and Damping Treatment.

Vibration testing, vibration analysis and design often involves the engineering of damping treatments, these pictures show a time domain ringdown used in estimating structural damping, a plot of the frequency response of a delicate structure with and without a tuned mass damper, the nomogram showing the temperature and frequency dependence of viscoelastic materials, and a photo of a sensitive actively controlled mirror for which we provided vibration consulting services to design a damping treatment.

We may also suggest modifications to control system parameters, or other system changes. We use our testing and analysis to explain why a system performs as it does, and why the modification will improve performance. Our experience allows us to be both efficient and thorough, minimizing troubleshooting, tool time, and prototype iterations.

We perform vibration Sensitivity Testing to determine the specification for allowable levels of Facility Vibration (and acoustic noise) for the system's installation. We also perform Site Evaluation measurements to verify that the proposed installation site (in the end-user's facility) provides an acceptable vibration and acoustic noise environment for the successful operation of the sensitive system. If facility problems are identified we often work with the facility owners to identify and solve the problem or to find a suitable alternative site for the system. The solution may involve reduction/isolation of the disturbance source, active cancellation of the disturbance at the sensitive tool, modification of the floor system, or tool improvement (such as with tuned mass dampers).

Some of the metrology equipment that we have worked on are SEM tools, FIB tools, TEM tool, AFM (atomic force microscope) systems, stylus profilometers, wafer steppers, interferometers, electron microscopes, CD SEM tools, elipsometers, and SPM tools which are manufactured by the companies such as KLA-Tencor, Veeco, Applied Materials, Rudolf Technologies, Nikon, Wyko, Zygo, Sensys, JEOL, Amray, Schlumberger, Thermawave, FEI, and Nanometrics.

Whether making a few dynamic measurements, or a full modal analysis, we use the concepts relating to the FRF and modal analysis to understand dynamic problems. We have over 30 years of experience making these measurements and solving structural dynamics issues. Our VP of Engineering, Henry Bittner, MSME, has been with our company, and in the field solving structural dynamics issues, for over 24 years. We love what we do and are at the very top of our unique field.

Our extensive Client List represents hundreds of projects, some involving days of work, others lasting several months, over the last 30+ years. Descriptions of many of our projects can be found in the left hand links under the various topics that describe our test, analysis, and design work. Our website is put together by our engineers.

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