The wheels of the MSXII were heavy, overbuilt, and kind of ugly. They were also difficult to manufacture since they required high-precision machining. However, it is not nearly difficult enough, and created too little of a mess, not to mention, it was too predictable.To fill in this void and bring chaos back into Midnight Sun, composite rims are being developed for MSXIV.
The MSXIV was modeled with aerodynamics in mind from the very start of the design process. The aerobody went through hundreds of iterations and simulations to perfect the airflow around it. However, these designs were build with the assumption that the wheel will not have spokes, since spokes, like miniature blenders, tend to create vortices and ruin a lot of the work put into fixing the aerodynamics of the car. If that wasn't enough, metallic spokes are quite heavy compared to composite ones. Carbon fiber wheels are the most popular for their great strengh-to-weight ration and aesthetic appeal. They have been used on many solar cars before, even being mass-manufactured by small companies such as Nomura Co. (https://www.facebook.com/NomuraCo/posts/16inch-carbon-fiber-wheel-2nd-batchdispatch-to-teams/1983506268560368/) and GHCraft (http://www.ghcraft.com/shops/cfw/cfw_16c_e.htm) exclusively for solar car teams . Some rims have been noted to decrease drag by ~5% and rotation inertia by 25%. These numbers will be used as part of the requirements for this project
Rim Simulations in ANSYS ACP
Oh god, don't even get me started.
Composites Testing
Before manufacturing the rims, the manufacturing process used needs to be validated through various tests of the composite materials used. There are multiple tests that are standard for any composite materials, and will be taken from general composites testing data used for other parts of the car: (1) tensile testing, (2) compression testing, (3) flexural strength testing, and (4) delamination tests. There are more specific tests to be done to test for the specific function and geometry of the rims. For now, this list includes: (5) pressure testing (80-120 psi), (6) buckling testing, and (7) environmental testing. The data can be used to validate the simulations done in ANSYS. More detail on each test and associated information:
- Tensile test
- Compression test
- Flexural st
Sources:
The Winning Solar Car.pdf
(I'll add more later I need to sleep soon)