Research Profile: Brad Kinsey, Testing the Mettle of Metals

Research Profile: Brad Kinsey, Testing the Mettle of Metals

Wednesday, October 17, 2012

By Sonia Scherr

Brad KinseyDo you drive a car? Drink out of soda cans? Use a washing machine? Travel by plane?

If so, Brad Kinsey’s research could have an impact on your daily activities. He studies how to better predict failure in sheet metal, the thin metal skin used in products ranging from retro Coca-Cola Zero bottles to the ultra-modern Boeing 787 Dreamliner. Kinsey’s research has the potential to improve manufacturing processes, because sheet metal undergoes stretching when it’s formed into a part.  

“Most people don’t think of sheet metal as stretching, but work hardening (stretching) the material strengthens it through changes at the atomic level,” says Kinsey, UNH professor of mechanical engineering. “However, if stretched too much, it will tear.”  

So it’s important to know how much stretching is too much. If manufacturers are more confident in how they expect the metal to behave, they can move more quickly from design to production and get their products into the marketplace faster. They can also use thinner pieces of metal. “If companies can shave a little bit of thickness off material, they will save significant amounts of money, which can be passed on to their customers”, Kinsey says. “Also, there are the obvious environmental benefits because fewer raw materials are used.”  

That’s true of many different products, including car parts and aluminum beverage cans (1.8 billion and 130 billion, respectively, each year in the U. S.). In the automotive and aerospace industries, less metal also means lighter, more fuel-efficient transportation. For instance, when an automobile sheds 100 pounds, it experiences a 1-2 percent improvement in fuel efficiency, according to the U.S. Department of Energy. For a driver filling a 15-gallon tank, that translates into a gasoline savings of between 45 cents and $1.05 with each visit to the pump.  

To estimate when sheet metal failure occurs, manufacturers traditionally have measured strain — the change in length of a material divided by the original length. One problem with this method, developed in the 1960s, is that the boundary between “safe” and “unsafe” strain changes based on how the material was stretched previously. Because multiple forming operations are used to create a given part, it’s hard to know which boundary to use. Still, Kinsey says, “manufacturers feel comfortable with this approach because they have used it for decades.”

Manufacturers can also estimate failure using a relatively new method based on stress — the force on the material divided by the area. Unlike with strain, the boundary between “safe” and “unsafe” stress seems not to depend on how the metal was stretched before. Kinsey investigates the effectiveness of this stress-based method of predicting sheet metal failure through analytical conversions (from strain to stress), computer simulations and experiments in the lab. “The verdict is still out as to whether the stress-based method will be more effective for manufacturers to use,” he says. For one beverage can manufacturer, however, the stress-based method has been a boon. “A company told me that, because of it, they’ve been able to reduce [can] thickness and save money,” Kinsey says.  

Kinsey, who believes research experience is a key part of an engineering education, strives to involve students in his projects. Of the 25 UNH alumni who worked with him as undergraduates over the past decade, 18 went on to pursue graduate studies, including five who entered Ph.D. programs. To meet the growing need for workers in science and engineering fields, “We need to encourage and promote research experiences to our undergraduates so they go on to get advanced degrees,” he says.  

Typically, one-third of the undergraduates in his lab are women — as compared with about 10 percent overall in the mechanical engineering program. He feels strongly about the need to attract more women to the field. “It’s a perspective that’s important to have,” Kinsey says. “I think everyone brings a different perspective to a discipline and if you exclude one set of people, then you exclude their perspective.”  

But it’s not just college students he wants to interest in engineering. He’s advisor to the UNH Robotics Club, which does outreach to young people through the Manchester-based FIRST organization, and has served as a mentor for FIRST’s Girls Connect program. He’s also the principal investigator on a National Science Foundation grant that brings middle- and high-school science teachers to campus to work with UNH faculty on research projects. The program’s aim is to help teachers become excited and knowledgeable about engineering so they can interest their students in the field. With several women faculty mentors, the program makes a special effort to attract women teachers, who then serve as role models for girls.  

Kinsey’s own passion for engineering began when he was growing up outside Flint, Michigan, the home of General Motors. In high school, Kinsey discovered he has an aptitude for math and science. When his parents’ answering machine stopped working, he dismantled it to find the broken part and fix it. “Like many budding engineers, I liked to take things apart to figure out how they worked.”  

Years later, he still does.