KINGSTON, R.I. -- August 7, 2000 -- With the ability to take pictures at a speed of 200 million frames per second, Arun Shukla's high-speed camera can make even the fastest moving objects look like they are standing still. In an effort to assist the military and a variety of industries, he is using this one-of-a-kind technology to study how things break apart.
"With this camera we can freeze the motion of anything that happens quickly," explained Shukla, distinguished professor of mechanical engineering at the University of Rhode Island and director of URI's Dynamic Photomechanics Lab. "It opens up a lot of possibilities for innovative research."
The camera was purchased through a $457,000 Major Research Instrumentation Grant from the National Science Foundation.
Shukla's primary focus is on studying catastrophic, rapid failures of structures, body armor, and other materials. He wants to know how these materials break apart, how much force it takes to break them, and how the materials can be improved so they can sustain even greater force before breaking up.
For example, Shukla is conducting ballistic studies for the U.S. Army on Kevlar body armor to improve the performance of bullet-proof vests.
"By evaluating how the material reacts when it is impacted by a bullet, we may be able to modify the geometric shape of the Kevlar and make it stronger," said Shukla. He believes that armor made with ridges on it is stronger than a flat piece of ceramic-backed kevlar. "Without the camera, we wouldn't be able to determine which shape is best."
He is also working with the U.S. Air Force to analyze how granite and concrete resist penetration from multiple impacts. According to Shukla, the Air Force is interested in this information to better understand the strength of underground bunkers, although the information is also of interest to the oil and gas exploration industry.
In addition to learning how things break apart, Shukla also uses the camera in the development of composite materials that are stronger or lighter weight than those currently in use.
By mixing concrete with cenospheres -- hollow, ceramic microballoons that are a byproduct of burning coal -- the concrete becomes considerably lighter. If he can develop a way of improving the bond between the concrete and the cenospheres, the lightweight concrete will be as strong, or stronger, than regular concrete. This work is being done under the auspices of the URI Transportation Research Center.
"We use the camera to analyze the fractures that occur between the materials under high load conditions," explained Shukla. "Once we understand how the fractures occur, we should be able to develop a better bond between the concrete and the cenospheres." Shukla began his studies of fracture mechanics using a camera he built himself in 1982.
"That first camera, which we still use, takes pictures at 800,000 frames per second, but it was very large and required 30,000 volts of electricity to operate, so some experiments took several days to complete. With the new portable camera we can do eight or ten experiments a day, and we can analyze the results immediately."
Shukla sees unlimited potential for the new camera, and he is open to inquiries from researchers throughout the region. He suggested that oceanographers or the Navy may be interested in using the camera to evaluate how torpedoes damage ships or to evaluate new materials and materials systems for use in emerging ship designs. He also believes forensic scientists could use it to analyze how bombs explode.
"The camera can do amazing things," he said. "There are probably lots of people who could find a use for it."
The above story is based on materials provided by University Of Rhode Island. Note: Materials may be edited for content and length.
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