With version 9.2 of the upright model passing simulations, the focus of the design could now shift to removing mass to optimize the weight of the part.

Topology Study

As a first step in the weight optimization process, a rough topology study was run to provide some insight on where mass could be removed. A major challenge in running Solidworks topology studies is that this type of simulation only works on parts, not assemblies. As a result, an equivalent part-level static structural simulation had to be set up, which loses some of the accuracy of an assembly-level study. The main difference between the part-level and assembly-level studies is that connectors like the bolted connections used to simulate the connection between the upright and the bearing caps cannot be used. As a substitute, the forces in the bolt holes were probed in the assembly-level study and manually applied to the part level study. This resulted in much higher max stresses than in the assembly study. This was acceptable though since this would only make the results of the topology study more conservative. Additionally, the topology study is not being used as a quantitative design tool. This approach was adapted from the following video:

Topology Studies Solving Big Problem One Step At A Time

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Upright top bolt holes forces.

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Upright bottom bolt hole forces.

First Mass Reduction

In the first revision to the upright, a series of cutouts were made in the low stress regions of the upright body. A truss-like supporting structure was left to maintain some strength.

The same assembly-level simulations used to evaluate the original upright were used to analyze the stresses in the revised part. The same load cases were used (see previous upright FEA report) along with a 5mm max node size for the meshes.

The max stresses in all the simulations were well below the yield strength of 7075-T6 (505MPa) and still mostly concentrated at the bolt holes. From this it was evident that more mass could be removed from the body of the upright.

Second Mass Reduction

The second mass-reduced design follows a similar truss-like cutout pattern as the first, with the major difference being that the cuts go through the entire part. Regions are preserved for the steering arm mounts and around the spindle hole.

The same assembly-level simulations used to evaluate the original upright were used to analyze the stresses in the second revised part. The same load cases were used (see previous upright FEA report) along with a 5mm max node size for the meshes.

Although the body of the upright is now experiencing higher stresses, they are still below the yield stress by a decent margin. This indicates that more material can be removed and/or thinner “trusses” can be used for the cutouts.

Next Steps

• Transfer cutouts to upright version 10 and run the simulations again.

• Remove more mass.