First we are pleased to announce the name for our newest solar car, which we will be taking to the 2017 Bridgestone World Solar Challenge, will be named Flux! On that note we are happy to say as well that our team is now officially registered for the 2017 Bridgestone World Solar Challenge.
It is now well into the fall semester, people are studying for finals, the leaves have fallen, and the team has been busy building Flux. The biggest part of this has been the composite layup (see below if you aren’t familiar with this) for Flux’s body. The molds for the upper and lower body were made by Custom Composite Technologies in Maine. We traveled to Maine on the weekends in order to complete all the layups that needed to be done. In total the team has been in Maine five weekends this semester from September through November. There were many late nights, but also some great times as well, such as the team trying to devour three 28-inch pizzas. Sadly the pizzas won. Between all of the weekends we manufactured: the canopy, the top body, and the lower body. We finished off by assembling the chassis and bonding it to the lower body. We have made amazing progress for one semester, and most of the composites work is almost done. Check out some of the pictures from the layup below.
What is a Composite Layup?
In order to make the car as light as possible we use composite materials, such as carbon fiber and Kevlar, as much as possible. Basically we use sheets of woven carbon fiber or kevlar that we then glue together to make a sheet with a high strength to weight ratio. However a single sheet is very thin and flexible. So we make a sandwich-panel where a sheet of honey-comb is sandwiched between two composite sheets. This increases the thickness of the panel making it stiffer.
Laying-up is the actual process of manufacturing a composite material. There are two main layup processes that the team uses: a wet layup, and a prepreg layup. In a wet layup the fibers start out dry. They need to be covered in epoxy before they can be placed on the mold. On the other hand a prepreg layup starts with fibers that are pre-impregnated (or prepreg) with epoxy. With wet layups the epoxy will cure in about a day, and you only have a few hours before it becomes semi-solid. So with wet layups the team has to move fast. Whereas with prepreg the epoxy will take about a month to cure at room temperature, so the work can go much slower. However to get prepreg to properly cure it needs to be heated up with a car-sized oven.