Winter 2024
Project Background
In my Design for Strength and Stiffness lab course, we were tasked to build a racing cart. The main criteria and constraints for this project were that it must cost less than $200 in materials, it must fit within 2.5’ x 6’, and the structure must be primarily PVC pipe. We decided to make a boat-themed cart that steers with a tiller and is propelled by another person pushing the pushbar from the back.
Design Process
As a team of 4 people (we called ourselves The Pirate’s Posse), we brainstormed potential designs and use cases, used hand calculations and FEA results to predicted expected stresses and deflections, worked in the machine shops to bring our design to reality, and tested it’s viability through testing with other students. The quarter culminated in a final presentation and report for our fellow classmates and our professor.
The hardest part of the design and construction process was the tiller mechanism. We wanted to decouple the friction on that axis from the weight of the rider, so with a suggestion from our professor, we decided to use a thrust bearing to rest in between the wooden plate and the slip hub. The slip hub (the white plastic piece shown below) didn’t fit our PVC width, so we needed to make a wooden adapter out of scrap wood we found in our school’s machine shop. With a drill, router, sander, and a few screws, we had a working tiller hinge. While it was functional, this was a weak point in our design since it was extremely susceptible to bumps in the riding surface.
During the design process, I worked on creating a CAD model and drawings that could be used by others to replicate and improve upon our design. We also had a more simplified model that was better suited for SolidWorks’ rudementary finite element analysis capabilities.
I learned a lot while working on this project. It was a great opportunity to apply my mechanics knowledge as well as get experience in the machine shop. I had a lot of fun working on it and the final product turned out amazing!
Final Report
With the consent of my teammates, I’ve attached our final report, which includes more details about the materials list, assembly drawings, and testing.