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EPISODE: The Engineering Physics Department Newsletter


Spring / Summer 2007
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Faculty Profile:
Matt Allen

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Matt Allen

Matt Allen (Larger image)

Faculty Profile: Matt Allen

Decorative initial cap Matt Allen always has enjoyed taking things apart to study how they work. So when he entered Brigham Young University as an undergraduate, he had no trouble selecting mechanical engineering to study. “Of all the disciplines in science and engineering, I chose mechanical engineering because I liked working on things that I could see,” he says. “But ironically, over the past few years I’ve found myself working more and more on things that are either too small to be seen, or that you physically can’t touch.”

Allen is the department’s newest assistant professor. His research falls into both experimental and modeling realms. He studies dynamics and vibrations, system identification, experimental modal analysis, the dynamics of micro and nano systems, uncertainty in dynamic systems, and stochastic dynamic systems. He helps maintain the department’s atomic force microscope laboratory and, beginning in fall, will teach in such areas as dynamics, vibrations, nanomechanics and experimental methods for dynamic systems.

Allen took a two-year break from his under-grad studies at Brigham Young University to work as a missionary in Guatemala. “Just long enough,” he says, “to develop a serious addic-tion to black beans and to forget every scrap of calculus that I had learned as a freshman.”

After completing his bachelor’s degree, he completed MS and PhD degrees at Georgia Institute of Technology. There, he developed an algorithm for detecting damage in structures. “The idea is to take vibration measurements from a structure, such as a bridge or the wing of an aircraft, and use the measurements to determine if the structure is damaged,” he says.

The algorithm can process data from many sensors, even in the presence of considerable noise, and then deliver an accurate estimation of vibration properties such as modal parameters and natural frequencies. Allen also applied it in studies of failure in the tiny solder bumps that fasten centimeter-square computer chips to a circuit board.

After he earned his PhD in 2005, he took a postdoctoral position in structural dynamics research at Sandia National Laboratories. His group devised methods to increase the life of high-speed micro-switches. Basically, his group tailored the electrical signal that closes the switches to reduce dynamic forces the switch experiences. “This would’ve been an easy task for a single switch, but the project required a solution that would work for an array of switches that were quite different from one another due to manufacturing variability,” he says.

By modeling uncertainty in the switch dimensions and material properties, he reduced switch-closing velocity by a factor of four.

Much of his research has been on inverse problems—in other words, measuring vibrations from a structure and then using them to determine a desired property. He began a piece of this work as an undergraduate during studies of carbon-fiber materials that include a special layer of viscoelastic material to improve their damping. “I developed a test system that could estimate the stiffness and damping of the material from the vibration measurements,” he says.

Allen has become interested in applying some of his inverse techniques to improving the dynamic or vibration performance of micro and nano devices. In atomic-force microscopy, for example, he might improve image resolution or sample scan-speed. “There might also be applications to biological systems,” he says. “Dynamic material characterization methods are sometimes more sensitive and easier to use than static methods.”

He also is studying ways to model systems of interconnected components when it is impractical or impossible to create finite-element models of all of the components. “We derive test-based models,” says Allen. “We test the structure to find its dynamic properties, and then attach that test-based model to a finite-element model for the rest of the structure. This idea has been around for some time, but we
have come up with some new ways of assuring that the process works, even when there are uncertainties in the models and test results.”

His group at Sandia applied this to weapons systems—in particular, parts supplied by other sources that weren’t practical to model. Allen is continuing this work under a grant from Sandia and also exploring other applications. “Satellite systems present an interesting challenge,” he says. “There are some systems that, because they’re designed for zero gravity, can’t be tested on Earth—yet each subcomponent could be tested on Earth. My goal is to improve these methods so that they can be used with confidence, even in high risk applications such as this.”

Allen also plans to continue an interest he developed in laser vibrometry, a method for measuring the motion of a structure without touching it. Currently, laser vibrometers measure a single point at a time. “But you can also sweep the laser over a surface continuously as you measure,” he says. “It turns out that the methods I’ve developed for time-varying systems can also be applied to laser vibrometry, allowing one to measure the vibration of a surface with a fraction of the time and effort that it takes using conventional techniques.”

If his theory proves true, researchers could obtain measurements faster and also could capture impact events that are difficult to replicate or a transient event like a force.

In his spare time, Allen and his wife, Melissa, enjoy spending time with their son, 6, and daughter, 4. A native of California, Allen also likes to mountain bike, play tennis, downhill ski, play the piano and edit home videos of his kids.


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Date last modified: Friday, 15-June-2007 11:49:00 CDT
Date created: 15-June-2007