Material of wishbone

[Ivar Revolve]

Well, the material we have chosen is far the best, yet unknown to most of the designers out there.
It woven hair from virgins of the utopian woods in Mongolia, hardened in sap from a redwood tree that has survived atlest 4 forest fires.
Dont forget to use a drop of sweat from abominable sea ??cucumbers or the mix will get too elastic.

[CameronBeaton]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Tallboy:
+1 on the bamboo. We use it to upsell our car as being environmentally friendly. </div></BLOCKQUOTE>

I´m not sure if your serious, but I was thinking as I was writing it 'this could work, not the best solution but it might be ok'

[Mbirt]

Has TU Graz been running bamboo or ostrich wishbones?

[Jan_Dressler]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mbirt:
Has TU Graz been running bamboo or ostrich wishbones? </div></BLOCKQUOTE>
Sorry, I can't tell...
Last time I've seen it, it was all covered by that black stripy looking stuff vinyl, like you glue on the hood of your Skyline...
But I think they use kangaroo bones, which might be the reason why There Are No Kangaroos In Austria

[Xeilos]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Jan_Dressler:
But I think they use kangaroo bones, which might be the reason why There Are No Kangaroos In Austria </div></BLOCKQUOTE>

+1

[Rex Chan]

Because I'm bored, I'll answer you question:

Mild steel or cromoly. Machine ends for press fitting of spherical bearings; then weld onto tubes. You'll have to do some engineering to work out how big (OD) to make your tubes, and how thick it should be. Should be related to forces being transferred to the chassis from the tyre&gt;wheel&gt;upright.

We have used cromoly for the past 2 years (2010/2011), because we can't get mild steel that small OD. We also use much thicker wall thickness than is required, again due to lack of choice.

In 2009, they used carbon fibre tubing glued onto machined aluminium bit, which had bearings glued into them. We didn't do it right, so the glue didn;t work very well. The bearings started to move around, the the tubes became unglued. They are however, noticeably lighter than the steel ones. I still wouldn't do it, cos steel is much cheaper, faster (less machining), and idiot proof. PLus, we can drive it pretty much anywhere without worrying about breaking them.

[swong46]

Quick question, how come you don't see square tubing being used when it has less bending stress per input force?

[ed_pratt]

swong46,

I'm sure someone else will answer at some point but firstly, you shouldn't really be getting bending in your wishbones.
Ok, real world, FSAE scenario, bad manufacturing and questionable design may result in some bending forces, but essentially they are supposed to be in tension or compression only.
Which brings us to the second point, if we are more concerned about buckling then there is less of a difference between the two. Which means we choose on a secondary point, drag.

ed

[swong46]

Thanks for the reply Ed.
Looking at the Euler buckling equation, square tube is still stronger.

I thought it was drag as well but when I analyzed the drag of a square tube A-Arm at 50mph, the drag increased by only ~0.01 lb per arm.

[vikram.]

different structure different advantages, if you will consider buckling square will take more buckling then circular
torsion, circular will take more torsion for same thickness
same with the case of shear square will take more shear than circular
bending, square can take approx 1.7 time the bending stress than circular.
the difference comes in weight.