Current weight: ~80lbs
Goal weight: <70lbs
How do we propose to do this?
Using the FSAE 2014 Rules Manual, the chassis team is looking into using alternative tubing which allows teams to use a smaller thickness tubing for structural members in the space frame. However, the rules also state that with a smaller thickness, there must be a corresponding increase in outer diameter (OD) to compensate for the loss in cross-sectional area (Rule T3.6).
… so wait a minute …
If the cross-sectional area needs to remain the same, then the volume of tube will not change– even with a decrease in wall thickness! And if the volume isn’t changing, then the weight of the chassis won’t either. So I have to assume that teams using a smaller wall thickness are doing so for purposes other than weight reduction.
To clarify our interpretation, we’ve submitted a rules question and are waiting to hear back from the FSAE judges. If they concur that we can’t reduce tube cross sectional area, we’ll have to optimize our triangulation methods to decrease weight while maintaining our torsional rigidity goals. We will verify this using finite element analysis through a software called ANSYS.
In the meantime, we will use specified and researched load cases to analyze FE1’s chassis in ANSYS and see where there is room for improvement. In spite of a wholly redesigned suspension and rear packaging, doing this analysis will provide a good foundation for this year’s design.