Initial Brainstorm & Design
When both sections of our team (α & Ω) met together to brainstorm, we initially had different ideas about what kinds of designs would be the most efficient at distributing the force evenly among the arm without allowing for too much displacement. Section α's design ideas were mainly centered around the distribution of multiple circular cuts through the arm to reduce the volume of and rounding the edges of the slots to decrease the amount of stress on the small corners (Best Score: 0.221 mm * in^3), while the designs from section Ω focused on hollowing out the arm to reduce volume and adding a lattice structure to support critical stress points in the arm(0.198 mm * in^3). Both of these initial design types seemed to be promising but didn't cut enough mass off on their own. After running a few simulations of each group's original designs, we came to the conclusion that both the initial design types had their merits and we decided to consolidate both into a single overlapping design.
Other design types that we tested and eventually decided to abandon included cutting the arm down to the end of the slots to form a smoother shape and reducing mass by cutting lots of tiny holes close together. Both of these tactics tended to rapidly increase displacement and from these trials we concluded that a smaller width or less dense body were more likely to cause the arm to bend than a firmer, more solid design. As a general rule, we avoided cutting off large pieces since we wanted to keep most of the rigid thickness intact. We also tried to focus on supporting the longer slot since that was where most of the stress was occurring.
The next few images show the progression of our model leading up to our finalized design.
This is an example of one of our earliest designs. We tried to cut out as much material as possible while retaining the structural integrity of the arm, but we quickly realized we needed more material to support the remainder of the arm.
We filleted nearly all the flat faces and corners on our model in order to shave off as much material as possible.
In this design, we tried to optimize hole placement in order to reduce the most material without creating stress zones that increased the displacement of our model.
Later on in the design process, we discovered that our design benefited most by having a point or segment of the arm that stayed rigid and we eliminated some of the fillets on the supports closest to the fixture of the arm.
After many, many trial and error sessions defined by the excel spreadsheet below, we finally arrived at this design, which is a culmination of all of our design steps.
Our final design had a final displacement of 0.2072 mm and a volume of 0.88 in^3. Our resulting score was approximately 0.182 mm * in^3.