Not many senior design projects give University of Utah mechanical engineering students a shot at a real gold medal.
But that was one of the inspirational aspects of building a sitski for U.S. Nordic athlete Sean Halsted, a Rathdrum, Idaho, resident who is competing in four events this week at the 2018 Winter Paralympics in Pyeongchang, South Korea.
“Inspirational? Oh my gosh, oh my gosh,” said Mike Stark, 34, leader of the six-person U. team that undertook assistant professor Michael Czabaj’s challenge to provide Halsted with modern equipment to replace the antiquated aluminum sitski he’d been using.
An Air Force veteran, Halsted was paralyzed when he fell 40 feet from a helicopter in a 1998 training exercise.
“I would have done anything to help. How better could I put my education to use? All of the guys had that spirit,” said Stark, a native of Oelwein, Iowa. “We compressed two semesters of work into one, going through the summer because we really cared and wanted to do well.”
And well they did.
“The sitski has far surpassed our expectations,” said John Farra, a U. graduate and Halsted’s coach on the U.S. Paralympic Nordic team.
Halsted came in 22nd and 14th in his first two races and was barely beaten in a sprint heat Thursday. He completed his 2018 Paralympic run with a 23rd in the 7.5-km race.
The idea for this project originated at a meeting of the Utah chapter of SAMPE (The Society for the Advancement of Material and Process Engineering), where Farra gave a talk about his skiers’ outdated equipment.
“Pretty much everyone in the room wanted to help out in some way,” said Czabaj, who got together with his Utah Composites Laboratory colleague Dan Adams to propose the sitski project.
“We were pretty confident about putting a good team together that could pull this off,” he added, noting that “designing and fabricating a high-performance, all-composite frame — customized for a specific athlete — is very challenging. [But] Salt Lake City/Utah has a vibrant composites industry and a lot of our students are very interested in composites-related projects.”
Stark headed the team, which also included James Calder, Martin Raming, Dalton Ostler, Zachary Sievert and Nick Miller.
A seventh student, Austin Bourret, focused on part of the ski’s binding and also helped complete the development of a third model of the sitski — the one taken to the Paralympics by Halsted, 47, who discovered Nordic skiing in 2001 at a U.S. Department of Veterans Affairs Winter Sports Clinic.
A rower in college at Washington State, Halsted improved relatively quickly as a sitskier and made it to the Paralympic World Cup circuit by 2008, finishing 16th overall in his discipline. He made the U.S. team for the Vancouver (2010) and Sochi (2014) Paralympics, his best finish being a ninth in a cross country race in Vancouver. Halsted’s Paralympic team bio for Pyeonchang says his top priority “is being a good dad to his three children.”
After accepting the project for Halsted in the spring of 2016, the U. team went to work immediately. They couldn’t wait until the school year started that fall because they knew they wanted to get Halsted a sitski by winter, so they met in May and worked through the summer.
“The biggest thing for us was a lack of understanding of the strengths and limitations the athlete had,” Stark said. Team members quickly found that although Halsted has limited mobility in his lower body, he still has some feeling.
“So you can’t just put him on a jagged frame. This sitski has to be more than light and cool. It needs to fit Sean perfectly,” he said. “We also had to figure out where we put padding without adding too much weight. We went from thinking this was a simple cakewalk to knowing this is a real, challenging, in-depth project.”
Much of their understanding evolved through scores of computer simulations.
“Our goal was to optimize the strength while minimizing the weight of the sitski,” said Miller, 33, a graduate of Rowland Hall High School now working as a design engineer for Chromalox in Ogden. “This involved adding [layers] of carbon fiber to specific areas [on the frame], removing them from others, or changing the orientation of the [layers].”
Calder, a 31-year-old graduate of Roy High School, used his experience in tooling to help manufacture three carbon fiber prototypes of the final sitski, each one getting a little lighter and better balanced while retaining the strength needed to withstand the pressure of high-stress turns. “The last ski was 3.3 pounds,” he said, a 40 percent weight reduction from the first.
The first version was the right design, shape and configuration, but it was a bit heavy,” Coach Farra said. “But they offered to try again and we were both very pleased, and surprised frankly, how much they were able to lighten it up seemingly without compromising the strength.”
Even better, the ski designed by the team enabled Halsted to get into and out of it on his own so that he was no longer dependent on having his wife or a friend around for help.
“We wanted to find a design that allowed him to pull his sitski out of the back seat of his car, to climb in, strap himself in and go,” said Stark. “There was freedom in that.”
The project hit close to home for Bourret, now a senior in the mechanical engineering department but a competitive moguls skier for 13 years. He designed and built a carbon-fiber binding that connects the ski to the rider’s saddle.
After watching Halsted compete in a live stream of an earlier Paralympic event, the 26-year-old from Sun Valley said, “Seeing that seat last night with Sean on it was extremely rewarding as an engineer and a former athlete. [I could] relate to Sean’s dream, trials and tribulations and what it takes to get to that point. With competition behind me, my goals have shifted to engineering. Being able to apply myself to produce something to help him achieve a similar goal feels great.”
Like his students, Czabaj found this project to be “one of the most rewarding things I’ve been involved with here at the U.” And he’s not done with it.
Besides beginning a long-term relationship with the U.S. Paralympic program, he hopes future senior projects will “fabricate versatile and high-performance frames for noncompetitive athletes who may want to give Nordic skiing a try but can’t afford the proper gear.”
Farra shares that dream.
“The basic design they have created could be used for other skiers with a spinal cord injury or other disability that requires that they be in a sitting position to enjoy cross country skiing,” he said. “I plan to reach out to the U. team and see if they are up for another round after the dust settles from the Games.”
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