SOCORRO, N.M. November 30, 2009 – This year’s seniors in materials engineering are tackling some complex and interesting projects for their Senior Design class.
|Materials engineering seniors Brandon Nation and Marcus Chavez prepare to test an explosive method of welding three layers of metal. They, along with Sean Hamilton, tested nine different methods and are finding interesting results. Courtesy Photo|
This is the first in a series of articles on Senior Design projects in the engineering disciplines.
The six students are working in two teams. Team 1 is Sean Hamilton, Marcus Chavez and Brandon Nation; they are developing an explosive method of welding multiple layers of metal in one action.
Team 2 is Cory Gibson, Ryan Cook and Taylor Wilkinson; they are working with sponsor Navair to design a fire-retardant wheel-well insert for military Hummers.
Both teams have regular contact with their sponsors and weekly meetings with instructor Dr. Diedre Hirschfeld. The students said the class gives them excellent experience working on problem-solving, engineering and collaboration.
“In the real world, you’re given a task and you work together as a team,” Chavez said. “This class simulates that.”
Nation said the Senior Design class wraps up the previous years of learning into one yearlong project. Wilkinson said the class asks students to learn for themselves.
“We can’t look in a text book for the answers,” she said. “We have to go out and learn things on our own. We work with our mentors, but we have to go find our own answers.”
“And there’s no one right answer,” Hamilton said. “But there are wrong answers.”
Hamilton said Senior Design represents the first time that the seniors have full freedom to pursue a project in a direction of their own choosing.
|Brandon Nation (right) and Sean Hamilton pour explosive powder into their test tray at the EMRTC test range. Courtesy Photo|
Wilkinson said the project also serves as an excellent transition from the academic experience to the career experience.
The explosives welding team is currently testing methods of joining three layers of metal, with a goal of eventually being able to weld four layers at once. They are using facilities at the Energetic Material Research and Testing Center to test their theories, but using explosives is not cheap and conducting experiments isn’t cheap either.
“The problem is doing it cheaply,” Hamilton said. “ANFO [ammonia nitrate-fuel oil] is the cheapest, but it doesn’t give us the detonation velocity we need.”
Nation said the team can’t test every theory and every explosive, so they are working with computer simulations and engineering theory to develop suitable explosive material and suitable testing parameters.
However, Chavez said computer simulation programs for this sort of activity are not well developed. Models can predict the speed of the flying plates, but cannot accurately predict the sort of bond.
So far, the team has conducted one test with ANFO with mixed results. The top two layers of metal bonded successfully. The bottom two layers, however, only partially bonded.
“Essentially, we varied the variables and got the same result,” Chavez said. “That helped clarify our direction. We’re making progress, but we have some more tests to do.”
They said that they probably learned more from the failure than they would have learned if the test had been successful.
“The test taught us a lot,” Nation said. “We’re moving forward with our conclusions. We’re able to eliminate things that engineers had thought were influential and found another variable that is important.”
Nation said they have found that the space in between each metal plate is not as important as previously thought. A key variable is the velocity of the plates; they believe they’ll need to achieve 6 kilometers per second to successfully create the second bond. Further, they’ve determined that an ANFO explosion will be insufficient to achieve the required velocity.
The Navair team is testing a variety of materials to design a wheel-well insert for military Hummers. Gibson said their challenge is to creating a composite design to make the vehicles safer. Due to the proprietary nature of the project, they are not allowed to discuss the details of their project.
Most of the team’s work will be research, but Cook said they will create a scaled prototype. They will then subject the prototype to fatigue testing to ensure that it will be robust and rugged enough to withstand harsh environmental elements.
“The challenges are unique,” Wilkinson said. “We have a chance to work on important research that will be widely used.”
– NMT –
By Thomas Guengerich/New Mexico Tech