FSAE Polyurethane Foam Seat Bolster Design and Manufacturing

 As a first-year member of Cal Poly Racing, I was tasked with designing cheap, lightweight, and easily manufacturable seats for both the combustion and electric formula vehicles. After discussing desires with drivers and exploring potential options, I decided to make polyurethane foam side bolsters to secure drivers.

A set of finished bolsters custom fit to one of our drivers

No seat had been used the previous year, and drivers expressed that the main concern they wanted the seat to resolve was excess horizontal movement since the harness already restricted them from lurching forward. Furthermore, they were not concerned with cushioning along their backside as they preferred to sit as low into the vehicle as possible. 

Based on these conversations, I decided it would be more effective to create bolsters that hugged the side of the drivers and filled the gap between them and the chassis, rather than create a full seat that would lift them up and require much longer manufacturing. The bolsters could be made of polyurethane boat foam and poured while drivers sat in the car to create a snug fit. The low cost and time commitment this process required allowed me to make a custom set of bolsters for each of our 5 drivers to get an ideal fit. 

I placed two large plastic bags on each side of the cockpit and had the driver sit inside. Next, the foam was poured into each bag and allowed to expand around the driver for ~10 minutes until mostly hardened. After 24 hours of setting, the bolsters were removed from the bags, and excess material was trimmed with the remaining bolster coated in Flex Seal. Finally, after drying, Velcro was added to hold them in place in the chassis, and they were tested in the car. 
~20 oz of liquid foam per bolster prior to pouring and mixing

One of our drivers sitting in the car as the foam was poured

Expanded foam molding around the driver's torso

Hardened bolsters before and after trimming and Flex Seal coating. Notches cut out to avoid making contact with the harness.

These seats were a simple yet effective solution to driver security while driving. 

Comments

Post a Comment

Popular posts from this blog

FSAE Drivetrain Structure Design

Image
 I am currently serving as Cal Poly Racing FSAE's drivetrain lead as we work to design, build, and test the highest-performing electric vehicle in our club's history, and ultimately win competition. I used NX and ANSYS to redesign and analyze our vehicle drivetrain structure. My design's primary goals were to be light, reliable, and manufacturable. I defined design requirements, designed for manufacturability, learned how to construct a subsystem of many components, sized bolts and bearings, sourced off-the-shelf components, and integrated my design into the overall vehicle build. Drivetrain Structure Assembly I began my design by defining the requirements it had to meet. These designs came from top-level vehicle design and technical direction, reliability/serviceability, testing optionality, and performance targets. Over the 2024 summer, I presented these requirements to my team and alumni in our Design Criteria Review where I provided detailed rationale for each target. I...
Read more

Longitudinal Acceleration MATLAB Simulation

Image
As Electric Drivetrain Lead, I developed a longitudinal acceleration simulation using MATLAB to analyze how various vehicle parameters influence straight-line performance and acceleration events for the FSAE competition. This simulation played a key role in selecting critical vehicle components, including the motor for the CP25E vehicle. The simulation took into account a wide range of parameters, such as vehicle mass, weight distribution, wheelbase, final drive ratio, aerodynamic characteristics, motor specifications, and weight transfer effects. The output data included detailed tractive effort plots, maximum speed, 75m track acceleration time, and traction-limited speed, which I used to assess overall vehicle performance. Tractive effort plot output for Emrax 208 Motor and mu = 1.7 Using this simulation tool, I was able to perform sensitivity analyses by sweeping vehicle parameter values to observe their impact on performance. This approach allowed me to identify optimal parameter r...
Read more

FSAE Cooling Testing and Pump Selection

Image
For the 2023-24 academic year, I led the electric drivetrain cooling management and optimization for the Cal Poly Racing CP24E vehicle. I analyzed the cooling requirements of drivetrain components, constructed a system curve for the previous year's cooling loop, and sourced a new pump that best fit the updated system design while reducing weight by 35%. I also developed a testing plan to measure the head loss within the cooling loop and applied system curve "k" constants to account for the head loss contributions of individual components, enabling precise adjustments to the overall system curve. Final System Curve I began this process by evaluating the cooling requirements for the critical components of the electric drivetrain (the motor and the motor controller): Motor Specifications Model Emrax 228 Cooling Type Liquid (Water) Minimum Coolant Flow Rate 8 L/min Max Coolant Temperature 50℃ Max Allowable Motor Temperature 120℃ Max Motor Temperature Experienced 60℃ Motor Con...
Read more