chassis material

[Reactive]

Hi,

We are a new team, planning to join formula SAE Italy. What I saw from benchmarking is most teams use steel tubing for their space frame chassis design. Why do most teams stay away from aluminum or carbon fiber monocoque structures?

Thanks all...

Hakki Can Koman

Engine and Drive Train
ITU Formula SAE Team

[Reactive]

Hi,

We are a new team, planning to join formula SAE Italy. What I saw from benchmarking is most teams use steel tubing for their space frame chassis design. Why do most teams stay away from aluminum or carbon fiber monocoque structures?

Thanks all...

Hakki Can Koman

Engine and Drive Train
ITU Formula SAE Team

[Jersey Tom]

The roll hoops have to be steel anyway so it makes attaching those much easier. Steel is easier to TIG for most people than Aluminum.. certainly easier to learn on. And CF monocoques take a *lot* of design and mold making to get right. And you can't just weld on tabs afterwards for stuff you forgot.

Steel.. cheap, easy, effective.

[Mike Claffey]

It takes alot of time and manpower to create a proper design process that will produce a good carbon chassis. Things like inserts, load paths, FEA and even the structural equivilency report will need to be researched and tested.

I'm not saying its beyond any team, but a large part of the racing community use steel spaceframes, and there is abundant and easily accessable information on this technology. With everything else involved in making a race car I think most teams go down the spaceframe route because it is most suitable for their resources (manpower, money, shop equipment and so on).

If your uni just happens to have an autoclave I would seriously suggest looking into a cf monocoque though http://fsae.com/groupee_common/emoticons/icon_wink.gif

Regards,

Mike

[LU-Bolton]

Money. Three years ago when we used to build steel frames, I could go out and buy the steel we needed for the frame and it would be here withing three days for less than a $1000(US).

Now that I design carbon fiber monocoques, I have to find someone that is gracious enough to support our team by giving us fiber, resin, bag material and all other consummables. (note-we build vacuum infused monocoques) It takes months sometimes to work out getting these materials and resources. If these materials weren't donated, our team wouldn't be able to afford building composite chasses. A carbon fiber chassis can easily be costed out at over $3,000-$4,000(US) after everything is said and done. Don't forget the molds you have to construct to build one.

I'm not trying to distract you from building one though. It has been very rewarding for our team to switch to this type of design. Just realize some of the compromises that are there if you decide to undertake it. On the bright side, each and every year your chassis will get better once you start learning how to design and build monocoques.

Aaron Cassebeer

[Parker]

wow it cost you $1000 for steel for your frame?? We get enough 4130 for Formula and Mini Baja for just over $600 USD. We are switching back to mild steel this year and it should be even less.

we would really like to build a composite monocoque but it is hard enough to get everyone to understand that this is a design competition over just rigging a car together...

[Jersey Tom]

Chassis and a-arms for us.. about 1 grand if all steel.

[LU-Bolton]

The $1000 was a conservative approximation of course. I haven't built a steel frame in a while while so I'm not up to speed with the costs. The only thing we use steel for anymore is roll hoops, and that's because it's required by rules. Otherwise they would be carbon fiber like every other component on our car other than the engine block and tires. http://fsae.com/groupee_common/emoticons/icon_smile.gif

Aaron Cassebeer

[Chris Boon]

Atleast with a steel frame if someone stacks it, you can cut tube and re-weld sections in a matter of a week, you stack a carbon monocoque and it cracks, I wouldnt be so certain on how youd fix it, or how structurally sound itd be? i know bugger all about carbon so these two questions could possibly be answered quite simply but i dont know.

[Jersey Tom]

If you want to be able to replace tube I'd go with brazing.

[KU_Racing]

i think the biggest reason teams stay away from aluminum is the heat treatment requirement. If we had an efficient way to heat treat our frame and keep it straight, id vote for a welded 6061 or brazed 7075 frame.