Hardness Testing Made Easy:
MTU Invention Licensed to Army Research Labs
If you've ever played around with Silly Putty, you know a little about
the difference between statics and dynamics. Pull a blob slowly and it
stretches; pull it quickly and it breaks. Measuring how materials behave under a static, slow pull is simple. Measuring
the effect of dynamic yank is another matter entirely, involving a lot
more math than the average technician is up to. At least until now. Five years ago, Professor Ghatu Subhash (MEEM) developed a prototype
of his dynamic hardness tester, the first device to easily and quickly
measure how materials respond to dynamic forces. He recently returned
from the U.S. Army's Aberdeen Proving Grounds, in Maryland, where he set
up his newly patented tester. For $40,000, the army became the first organization
to purchase a license for the device. Nevertheless, says Subhash, looks can be deceiving. "We developed
a lot of science and published a lot of papers on this, my students and
I," he notes. "It's more complicated than it seems. "It's like firing a bullet, making it kiss the target and come back." Dynamic hardness testing has been around for a while, but it wasn't easy.
Subhash's tester has taken the difficulty out of the process. "Now
you don't need a PhD to do it," he said. "Any high school student
or machinist can use this." In time, dynamic hardness testers will be evaluating materials in labs
and machine shops all over the country, Subhash predicts. Anyone researching
or manufacturing materials in areas as diverse as bullet-proof clothing,
automotive crash-worthiness and precision grinding can learn a lot from
a dynamic hardness tester. And if the device were to be licensed and manufactured,
then the price could be affordable for the average machine shop, he said. Jim Baker, director of technology partnerships, agreed. "The equipment
isn't so exotic that only the army can have one," he said. "It's
inexpensive enough so that any machine shop that wanted it could have
it." The University has applied for a Canadian patent on the dynamic hardness
tester and is also working with another company to license it.
At
first blush, it doesn't look like $40,000 worth of machine. There's a
long bar with a power source at one end, a point at the other, and a weight
in the middle.
