I was wondering what materials (Carbon, Kevlar, S-2 glass, epoxy etc) make up the outer skin of some of the Indy, Formula 1 or other race car types that might use composites on outer shells etc. Particularly interested in the examples of the weight of fabrics and type. Like do some some use 10 layers of 10 oz carbon then 5 layers of 6 oz kevlar, or 1 layer of carbon then 1 layer of kevlar or something like that. I have no idea and was just curious to see how they do it or how you think they do.
Multi layers of Pre-Preg carbon fiber in many different directions, vacuum bagged and then Auto claved at elvated pressures and temperature.
dependinig on the part they use a complex prepeg , core and more prepeg, core can be honeycomb nomex, aluminum or special top secret stuff. I saw what looked like carbon honeycomb when picking up some broken indy car pieces. The pre preg can be multi layered at precise angles before it is impregmated with resin.
Pre-preg is always pre-impregated with the epoxy resin when it is made!
No Kevlar? I thought they would use it for abrasion resistance and durability…or do the multilayers of prepeg provide this?
One thing you have to consider, on F1, Indy, Champ Car, the main tub is a structural part. The front suspension is bolted to the front tub. The rear suspension is bolted to the transmission, which is bolted to the engine, which is bolted to the main tub. So the loadings on the tub is quite high.
The main tub is constructed of pre-preg carbon fiber with nomex or aluminum honeycomb sandwich in the middle. Most of the carbon fiber will be unidirectional. The typcial woven carbon fiber is not as strong as the unidirectional. Woven carbon fiber also retains more resin which is not good for weight or strength. The lay up schedule is determined by the loadings each element will have. The number of layers is determine by the load and also by the rules. Each organization have a minimum thickness requirement, especially for the main tub. Most are 5mm or thicker. The math involved to determine the loading isn’t difficult, but it is very time consuming. The big guys will developed their own software to analyze each particular element.
Since monocoque construction is still a aerospace thing, most composite parts in a race car are molded in sections then riveted and bonded together.
Kevlar is typically not used because abrasion resistance and durability is not a requirement in a race car. Material selection is a critical part of designing a race car. You don’t choose a particular material just because it’s cool. There are certain situation where kevlar is used. Some open wheel racing does require a tether to keep the wheels from flying away. Rally cars will have kevlar in certain areas underneath the car for skid plates, but critical areas are still aluminum or steel.
I believe that they are now making the tubs in one piece.
I have a book showing the construction of a two piece tub. They rivet and bond the two together after the bulkheads are bonded.
I want to learn this math. Any pointers for beginners? Thanks.
I have seen VER Pre-preg before but never played with it. As far as aluminum honeycomb, what company would you suggest as a good supplier?
I’m bad…just last week was our Spring break (ya, right as I was down there more than at home…) and was going thru a file cabinet and I found some manufactors samples that were pre-preg with PER (?) or Vinly ester…doh…
Perhaps I was unclear, The resin is almost always epoxy but the angles of the reinforcement a custom laid at the factory before they are impregnataed and shipped to the builder, mostly uni at 0 +45, 90, -45, sometimes they use funny angles for one section and I have even seen some twill in some areas, mostly wing endcaps and brake ducts though, I have also seen black honeycomb used (broken part), I don’t know if was nomex that was died by using a black colored epoxy or if it was some super secret high tech stuff.