The component that constrains the wheels to the suspension is called the suspension upright. It is a vital component requires deliberate optimization and analysis. The upright is an un-sprung part of the suspension, which means its mass contributes not only to inertia of the car, but it also contributes to load variation in the tires. Meaning, the mass of our suspension uprights is very critical.

The other consideration with the suspension uprights is cost. Due to the cost of machine time and the size of raw stock required, we have to optimize for manufacturability. 

Solution

Designing this part required a careful balance of topology optimization and design for manufacturing. I began by calculating a load case from our expected cornering condition and applying that specific load case to the previous year's upright. I fixed some of the geometry issues and smoothed out areas with stress concentrations. From there it was a matter of designing new iterations until we saw an even loading across the part and saw acceptable compliance values from the finite element analysis. I actually saw that we went over compliance targets before I reached our target safety factor so I ended up with a safety factor of 3.9, but still a 19% reduction in mass from the previous year. 

What I could do better

1. We were compliance limited but we didn't set actual targets for how much compliance was acceptable, we hit our mass goal and were above safety factor, but our compliance wasn't properly analyzed. 

2. Depending on compliance targets, I could have taken material out of the side supports. Despite my initial skepticism, according to the machinist,  this was a viable option.

Specs:

Mass: 0.559kg

Max Stress: 128MPA

Material: 7075 t6 aluminum

Safety Factor:  3.9