Using SOLIDWORKS, a team of students has designed an open-wheel vehicle for a Society of Automotive Engineers competition.
The other teams don’t see it. They see a mud-splattered open-wheel vehicle blasting past them in the dirt. They see it flying over jumps (see Figure 1). They see it swerving through a sandy slalom, and they see Tennessee Technical University students taking home another trophy. But what they don’t see is the work that went into that success.
They don’t see the students on the Tennessee Tech Baja Society of Automotive Engineers (SAE) team working in the shop long after the other students on campus have gone home for the holidays. They don’t see the repeated test runs tweaking every last bit of performance from the custom-designed continuously variable transmission. They don’t see the evenings and weekends spent on SOLIDWORKS optimizing 3D designs, looking to save every ounce, while stiffening every joint. The other teams see the success, but they don’t see the effort that goes in to making Tennessee Tech the most dominant team in Baja SAE history.
Baja SAE is an engineering design challenge organized by the SAE for university students. For 40 years, SAE has challenged students to design, build and test a single-seat, all-terrain sporting vehicle. With hundreds of teams and competitions on four continents university students around the world have risen to the challenge, but nowhere more so than in Cookeville, home to Tennessee Technical University and Dale Wilson, who has been the team’s faculty advisor for the past 17 years.
“Even people around here ask about that,” he replied when asked if there is a secret to the team’s success. “There are several things that you have to have come together.”He credits the students first. “You’ve got to have good raw material. The students come in with a good ‘hands-on’ skill set and an interest in off-road racing.”
He credits the university for supporting and valuing the competition as a meaningful part of education (see Figure 2) and, when pressed, admits that he has made a contribution too. “I don’t do any design or work on the car at all, but you do need a mentor and champion for the team on campus, not just a faculty advisor who signs off on the paperwork.”
He also credits his predecessors on the team, as the team has been competing at a top level for decades. “Success breeds success. It’s a university club—the team is 85 to 90 percent mechanical engineers, but it’s open to anyone on campus. We spend the first year or so teaching them shop skills and then move on to teaching the design skills. We make sure the students put school first, maintain their grades and are good citizens on campus.” The effort pays off, not just in trophies, but in the real world. “Employers are excited to get students with these kinds of hands-on skills and leadership skills,” he added.
One of those students is Samuel Foster, a junior in mechanical engineering and the team captain. Baja SAE is Foster’s first motorsport racing experience, but you wouldn’t guess that from his depth of knowledge and enthusiasm. “When I first joined, I heard about a club where you get to drive a race car, but driving is a very small part of what we do. You get to design the car from the ground up. You do the research, the design work, tune it… and make repairs.”
In true engineering fashion, however, his vision of “repair” doesn’t just involve fixing the problem, but understanding the problem and ensuring that it won’t happen again. He describes how a stress concentration in a previous year’s vehicle caused the suspension to fail. The exact cause of the failure wasn’t apparent until the team simulated the design and loading.
“The upper A arms would develop a crack due to braking forces,” he explained. “We developed a new design and ran several simulations to address the stress points in finite element analysis(FEA).” Confident that their new design would withstand the rigors of racing, they modified the vehicle. “It’s strong now, and we’re very happy with it,” he told me.
The simulation tools built into SOLIDWORKS also play an extensive role in Foster’s current design work (see Figure 3) . He is working to update their vehicle frame for the upcoming race season. “Pretty much everything relies on the frame. We really like the frame we have, so we’re just making small changes,” he said, mentioning that they have found small weight reductions and ways to increase frame stiffness through their computer models. As with any design project, however, there are external constraints that need to be considered.
“There are a lot of safety rules, and most of them deal with the frame,” he explained, describing how computer simulations can show that the frame will be able to deliver high performance while keeping the driver safe in the event of a crash (see Figure 4). “Next year, we want to make the frame the absolute best that it can be.”
Foster isn’t the only student tweaking models for maximum performance. Most of the team is involved in some aspect of the vehicle design. “They get experience with SOLIDWORKS on campus and in co-op programs and internships,” explained Wilson. “By the time they are ready to work on the car design, they are ready to use the software.”
Foster explained how the team has about 10 to 15 different people working on different parts of the car, submitting their work to a lead designer who integrates their efforts. “Next year’s design is coming together on the computer right now,” he said. “So far, we’ve got everything from the firewall forward done. We do FEA on pretty much everything.”
A recent initiative by the team has taken their CAD work to a new level of thoroughness, modeling the vehicle down to the “last washer and spring,” according to Wilson. The eventual plan is to upload the car into a 3D virtual environment at a facility on campus known as “The CAVE,” but, at present, this thoroughness is earning the team kudos in their design presentations and in helping new team members learn to maintain and repair the vehicle.
While CAD and simulation help the team to optimize their designs, ultimately they need to prove their simulations in the real world. That’s where having the support of the school community really makes a difference. One of their current areas of research is to improve their vehicle’s acceleration by optimizing their continuously variable transmission (CVT). “The campus police will come by with their radar to help check speeds,” said Wilson. “We have a test facility on campus for off-road testing, but right by the shop is a dead-end street they can block off to run tests to tune the CVT.”
The hard work and commitment of the Tennessee Tech Baja SAE team has definitely paid off. After four decades of competition, they have finished in the top 10 in over 80 percent of their competitions and won 12 first-place finishes, making the team the leading national champion in Baja SAE and making Tennessee Tech grads very desirable for their hands-on skill, leadership ability, engineering know-how and attention to detail. “The students are always looking for that little edge,” concluded Wilson. “That’s why employers love to come here.”
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