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ASME organized annual collegiate design-build-race competitions called the Human Powered Vehicle Challenge, where 20+ teams competed in Design, Sprint, and Endurance events.
Cal Poly SLO's 2015 entry, "Sweet Phoenix," was a fast and easy-to-learn tricycle. I was part of the 3-person Senior Project design team. Sweet Phoenix placed 1st in Design and Men's Sprint at HPVC 2015.
Cal Poly Human Powered Vehicle Club members at HPVC 2015
I held two major roles for 2014-15: Club President and Design Engineer.
As Club President, I organized 20 volunteers in weekly work sessions throughout a 6-month build effort. We empowered team members from all academic majors who wanted to contribute to design and fabrication of the vehicle.
As Design Engineer on the 3-person Senior Project team, I focused on vehicle controls and ergonomics. I was responsible for steering systems and components, vehicle dynamics, and rider ergonomics. I also helped design the monocoque structure and developed manufacturing processes.
Gantt chart for vehicle fabrication and testing
Fairing layups are a team effort
Tricycle prototype with adjustable steering ratios
Fit jig with fairing test
Vehicle dynamics design was driven by preventing tip-over instability during various safety and performance maneuvers informed by historic HPVC race course designs. I used these analyses to select a wheel layout and rider position.
I designed a handling prototype with adjustable steering ratios, which allowed the team to provide input on handing sensitivity and body position.
I also designed and fabricated an adjustable, stationary fit jig that was used for rider measurements, fairing shape testing, rider training, and performance testing.
Once the fairing shape was finalized, we designed a structural frame to support static, dynamic, and abuse loads.
Another team member designed ribs for the fairing with various sizes, core materials, and layup schedules.Â
I designed weldments of thin-wall steel tubes that were used to mount wheels, drivetrain, and steering systems to the fairing floor.
I performed FEA for the steel components, aiming to maximizing strength to weight ratio.
Fairing rib layup curing in a vacuum bag
Frame alingnment jig
We fabricated all structural components ourselves, in-house. I was responsible for organizing the 10+ composite layups it took to make the fairing sections, add structural elements, and join the fairing sections together.
I also designed a frame alignment jig to ensure steel weldments ended up in the correct locations on the fairing floor.
Test setup for lateral load applied to rollbar
Failed threaded inserts
We performed structural testing of the most critical safety structures to validate FEA. I designed a test fixturing method for the rollbar that replicated FEA constraints and loads, and ensured safety precautions were followed during the test.
The composite structure passed the test, but the threaded inserts used to fixture the rollbar failed. We changed the insert material from plastic to steel for the final build, and had no issues with the rollbar during our competition
Braking distance test
Adding struts to add lateral stiffness
I also tested vehicle dynamics and confirmed that we could perform the required safety maneuvers required at HPVC.
However, during dynamic testing it became apparent that the pedal mount had excessive lateral deflection. Bracing struts were added to the frame and fixed the problem.
Highlighted Results at ASME HPVC 2015, Western North America:
1st, Design
1st, Men's Sprint
4th, Women's Sprint
7th, overall
Special Award: Best Craftsmanship
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