FSAE Topology Optimized Bracket

Our school's Formula SAE team is a team focused on the engineering design challenge of building a racecar. Since this extracurricular is internationally recognized, we have to build a car that follows internationally regulated rules, and we get to compete with teams from all over the world. One of the components that is required to be mounted on the chassis is the jacking bar, which has it's own set of rules. As a first year student on the team, the upperclassmen asked me to design brackets that would mount the jacking bar onto the chassis in a rules compliant way, while also taking the opportunity to learn more about topology optimization. 

I began this process by taking a predetermined base shape (left) that my mentor helped me construct, and setting up a topology study in Solidworks to remove unnecessary material. Most of the initial revision was us reducing the size of the base shape as much as possible while remaining rules compliant. The image above depicts my first draft. 

I repeated the process of revising the input shape several more times. The most accurate way to validate the shape in the CAD was to create a part based on the topology results, and then run FEA on the part and bigger assembly to decide if it would be strong enough.  This was important because the topology results were a mesh that I could base my part on, but because of manufacturing constraints, my part would never be identical to the mesh. It was important to assess the strength of the part itself. The revision above shows a version of the part that we decided was not strong enough for our purposes based on FEA results. 

 After several more design revisions, I found a shape that distributed the upward load on the jacking bar in a more consistent way, within the factor of safety range we were comfortable with. My part geometry differs from the shape optimized part in several ways, because of manufacturing constraints. We decided to use a waterjet to cut out the pieces for the part, which meant that each piece had to be a completely flat. You can see where I decided to make the bottom piece of the assembly flat instead of diagonal in the Solidworks assembly images to ease manufacturing efforts. 

Team members at our design lab helped me use the waterjet to cut out the pieces for the brackets. I had left a generous tolerance to ensure the pieces would fit together. Then we assembled them and welded them onto the back of the chassis, and conneected the jacking bar to both brackets. I was happy to have the opportunity to manufacture something I designed. I think following through an entire design process to the manufacturing helped teach me to be mindful of how my parts will be manufactured, as I am designing them. The last photo on the right is of our completed FSAE 2023 car, on display at one of our school's venues.