College of Engineering News • Iowa State University

Darrel Enyart: All in a day’s work

MatE non-traditional grad student balances work, research, the military and a family

Graduate school has a reputation for being difficult and time-consuming, but Ph.D. student Darrel Enyart has had an especially challenging journey. Enyart spends his time on Iowa State’s campus both as an assistant scientist for the Center for Nondestructive Evaluation (CNDE) and as a graduate student researching materials science and nondestructive evaluation (NDE) for his Ph.D. research.

His graduate work looks largely at evaluating anhydrous ammonia tanks which are commonly used by farmers to hold fertilizer before it is applied to their field. “There are roughly 200,000 tanks in service across the country and sometimes they break catastrophically without warning,” says Enyart. “The contents are toxic to humans at moderate concentrations, so if you breathe in a significant amount it can be very bad, even deadly.”

Enyart’s team tests for stress-corrosion cracks in the metal body of the tanks. The weaknesses are often caused by stress created from welds in which one part of the metal contracts after cooling more than another part, leaving the pieces in a state of tension. Enyart looks specifically at how NDE can be used to recognize these flaws and predict if a tank is safe to remain in service.

For CNDE, Enyart is versed in all of the basic methods of NDE and specializes in select advanced areas. One of these advanced areas is phase-array ultrasonic testing (PAUT). PAUT projects usually involve companies sponsoring CNDE to improve inspection of their products or materials. “Companies will come up with a new material or microstructure that’s really good for making something like turbine engines, but this material or part geometry can be very difficult to inspect,” Enyart says. “ We’ve got to be able to find little, tiny flaws in that exotic material or the engine could blow apart when they run it at full power.”

Enyart also works in the Center for Industrial Research and Service’s Company Assistance NDE Group. The team helps Iowa companies evaluate their products with basic NDE methods using funding from economic development within the state of Iowa. “That’s always been a fun program because the products you evaluate are so diverse and you’re helping local companies with affordable and top-notch consulting.”

His interest in NDE began as an undergraduate at Iowa State when he was in the materials engineering program. “My brother, who also went to Iowa State and studied ceramics engineering before it became the materials engineering program, took the NDE course as a tech elective and said I’d love it,” Enyart recalls. “Having a background as a mechanic and growing up on a farm fixing things got me interested in how materials work and fail. Having NDE as a tool for interrogating materials is a really cool fit.”

While he enjoyed the discipline, Enyart didn’t always have NDE research of anhydrous tanks in mind for his Ph.D. work. He has worked on at least six different research projects that have fallen through because of a lack of funding and external interest. One of his projects came to a halt when Enyart’s major professor, Bruce Thompson, tragically passed away.

Eventually Enyart looked into anhydrous ammonia tanks for what was the second time. “The first time around I wasn’t really doing it as a grad student, I was doing it as a staff member at CNDE. The opportunity came up and I really think this could be the one with enough funding and the right fit with my full-time work.”

Research isn’t the only thing that Enyart has been working on recently. Aside from having a wife and two girls (who are 10- and 3-years-old), Enyart has spent 17 years in the Iowa National Guard and 3 years in active duty Army.

While on active duty, Enyart spent time in Bosnia and recalls being at a base camp on guard duty. “A good day is when nothing bad happens and a bad day is when bad stuff happens.” He had also been called up for deployment as part of the Boone Army Guard Unit and then released twice because his skillset as a truck mechanic hadn’t been needed. After the second release, Enyart took an opportunity to join the Air Guard Unit in Des Moines in a nondestructive inspection position, and has been a part of that unit ever since.

Between his full-time job, his Ph.D. work, and his time with the military, Enyart says it’s hard to spend the time he would like to with his family. “My wife works mostly nights and three weekends a month for her job, and the one weekend she has off is usually the weekend I have guard drill, so family time is really any time that we’re together.”

Enyart uses his journey to help mentor younger grad students. “With all of my experience in grad school and with my job as a staff member, I’ve been where a lot of these students are. If you have poor supervision, you end up spinning around and feeling like you have no resources.” Enyart says he tries to help students find the resources they need, such as funding, equipment or materials. “I think every university has an opportunity to do a better job with mentoring grad students so I want to help in any way I can.”