Suggest materials for a f3 chassis.

[p4_prateek]

Hi guys,
I'm building the chassis for a Formula car for FSAE. Can u please suggest some materials that are both light and strong enough apart from carbon fibre.

[riff_raff]

p4_prateek,

Check the rules first. I believe FSAE requires round alloy steel tube frames.

http://students.sae.org/competitions/fo ... erules.pdf

Light and strong means a properly triangulated space frame.

Good luck.
Terry

[xxChrisxx]

Above

+1 to this

They have to be space frame, as far as I can remember you can't have load beading panels apart from the floor.

IF you have a large budget 4130 Chrome moly steel will be the weapon of choice.
If you only have a small budget, its mild steel for you.

[p4_prateek]

Thanks a lot Chris for the info.

[p4_prateek]

Hey Chris,
I just found out that the values of tensile srength, density, modulus of elasticity and yield are almost the same for AISI 4000 Alloy steel and Cold drawn steel. so y do u prefer chromoly over CDS?

[xxChrisxx]

It's just the de facto standard steel for motorsport related activities so ive never bothered even looking at other steels.

Chrome moly is a low carbon steel meaning it welds really well. But it can also be heat treated to give a very hard surface finish that makis it very wear resistant.

4130 is bloody expensive though, you need to weigth that up against your specific needs.
Tbh for something like FSAE you can get away with cheap mild steel.

[bassimon]

Hi.

p4_prateek,
Check the rules first. I believe FSAE requires round alloy steel tube frames.
[...]

The baseline frame for FSAE is a steel spaceframe but the new rules for 2010 are enlarged by square steel tubings for various intersections which can be used without the need of an approved SEF. You can find the specified dimensions in section B.3 of the 2010 FSAE rules.

Above

+1 to this

They have to be space frame, as far as I can remember you can't have load beading panels apart from the floor.

IF you have a large budget 4130 Chrome moly steel will be the weapon of choice.
If you only have a small budget, its mild steel for you.

sorry, i disagree. The frame of a FSAE car has not necessarily to be a spaceframe and you can use shearpanels in a spaceframe where you want to. Of course you have to do an approved SEF if you substitute part of the side impact structure for example.
Apart from steel spaceframes have seen FSAE cars with carbon fibre monocoques, aluminum monocoques, glass fibre monocoques and even carbon fibre spaceframes. However, i would strongly advise every new team to start with a steel spaceframe.

B3.5 Alternative Steel Tubing [...]
Note 1: All steel is treated equally - there is no allowance for alloy steel tubing, e.g. SAE 4310, to have a thinner wall thickness than that used with mild steel

As p4_prateek already figured out, the use of alloy and high alloy steel is not as beneficial as one might think. On that part please read this: http://www.formulastudent.de/academy/pa ... e-chassis/
The author Pat Clarke is one of the senior Design Judges in Formula Student Germany and FSAE Australasia.

Regards,
Simon

[xxChrisxx]

sorry, i disagree. The frame of a FSAE car has not necessarily to be a spaceframe and you can use shearpanels in a spaceframe where you want to. Of course you have to do an approved SEF if you substitute part of the side impact structure for example.
Apart from steel spaceframes have seen FSAE cars with carbon fibre monocoques, aluminum monocoques, glass fibre monocoques and even carbon fibre spaceframes. However, i would strongly advise every new team to start with a steel spaceframe.

It appears I remembered wrong then.

[sticky667]

It's just the de facto standard steel for motorsport related activities so ive never bothered even looking at other steels.

Chrome moly is a low carbon steel meaning it welds really well. But it can also be heat treated to give a very hard surface finish that makis it very wear resistant.

4130 is bloody expensive though, you need to weigth that up against your specific needs.
Tbh for something like FSAE you can get away with cheap mild steel.

Actually Chrome moly welds very well but weakens from it's original hardness unless it's re-treated after welding. Mild steel would be the better choice, and it's cheaper.

[Jersey Tom]

Actually Chrome moly welds very well but weakens from it's original hardness unless it's re-treated after welding. Mild steel would be the better choice, and it's cheaper.

Ehh not really true. If you use ER70-S2 filler it's designed to have a ~70KSI strength in the as-welded condition, so the weld pool will have about the same strength as Cond N (normalized) 4130. The 4130 base metal just outside the weld pool, in the HAZ, GAINS strength and hardness. I wouldn't be surprised if it got above 45HRC. Brittle is what it becomes.

Even then, there's no NEED to heat treat a 4130 frame after welding. I've had years of cars like that, never a crack or failure. When designed right, for stiffness, there's a huge FOS from a stress standpoint. Plus if you were to try just doing the whole frame in an oven your suspension and engine points will move all over the place. If anything, you'd have to keep your frame in its jig and flame normalize the joints. But then you have the issue of how that lowers the strength in the low(er) carbon weld pool.

In any event, if you know where to look, 4130 is cheap. Couple years ago we got all the steel for our chassis AND suspension, for less than $500, including shipping!

AND if you try to use mild steel you are really limited on tubing size, whereas 4130 is available in a wide array of diameters and wall thicknesses.

[johnny99]

Look at T45 instead of 4130, its a lot easier to use. Google "Winged Aviation" and give them a call if your building a spaceframe. They have another new material, which is to replace CDS, called "Clubman 500". They are a wealth of knowledge, keenly priced, and have been supplying the motorsport industry in Europe for a long time.

John

[Yudhir]

Hi guys,
I'm building the chassis for a Formula car for FSAE. Can u please suggest some materials that are both light and strong enough apart from carbon fibre.

Hi there,
i actually need some help for my final year project.
i am a mechanical student and i have got a project concerning formula student chassis. but i dont know much about the formula student chassis.what does this chassis consist of exactly, e.g suspension driving axle etc?
also what type of dynamic force will there be on the chassis?
my project is on dynamic analysis of a formula student chassis.
thanks