Requirements specification for uprights to chose material

[Dean4.0]

At our school we did a subject methodic Materials Selection in Mechanical Design.
A friend and i chose as a practical project to chose a Material for a Upright to use in motorsports. For that, we first what to define the requirements specification.
We did a first brainstorming, what do you think is important and missing?


-minimal weight but high stiffness  high E modulus  minimal density
- because of high brake temperature  high maximum service temperature (What is high enough ?)
-high bend and drag stress  high Yield strength
-Fatigue strength at 107 cycles  high (What is high enough?) ;
because of long race distance and expensive fabrication of the uprights. Is that relevant? I Think yes for Amateur racing and so on but I think not absolute for formula 1 because they have so much money that they can build a new one after a few races, or is that incorrect assumption, I don´t now?

I know the price of the raw material and the fabrication is also a point we have to chose. But first we want to find the most important mechanical and design requirements and so on.
I think we have also to decide for what class of Motorsport we search a Material because of the price limiting and fabrication price. In formula 1 there is no problem but at Amateur racing and perhaps Touring cars GT1/GT3 and other secondary growth formula series and so on.
Does any one has any info because of Price limiting for the secondary growth formula series GP2, Formula BMW, Formula 3, and others like FIA GT1,GT3 etc.

Thank you!

[Belatti]

I suggest you to start doing a free body diagram of the part you are going to design.

Choose a car known ebough to estimate mass (from 1000 to 1300Kg in a touring car, 600Kg in a formula car), centre of gravity height (from 0.2 to 0.5 metres according to the car) and maximum acceleration (longitudinal and lateral) (1.7 Gs for touring, 2.5 Gs for F3 furmulas)

With those you can estimate the force the upright will have to bear. Add your security factors according to your estimates.

Then you will be able to do cross section / material comparison. This will lead you to calculate weight of the upright and considerate other things such as aero (if you calculate for an open wheeler)

To have some ballpark numbers, a 680Kg steel chasis sportproto with 150HP capable of developing 1.75 Gs with a CoGh of 0.3m has circular section Øe22mm Øi18mm uprights (simple cheap SAE 1010).

Hope that helps.

[Belatti]

-minimal weight but high stiffness  high E modulus  minimal density
- because of high brake temperature  high maximum service temperature (What is high enough ?)
-high bend and drag stress  high Yield strength
-Fatigue strength at 107 cycles  high (What is high enough?) ;
because of long race distance and expensive fabrication of the uprights. Is that relevant? I Think yes for Amateur racing and so on but I think not absolute for formula 1 because they have so much money that they can build a new one after a few races, or is that incorrect assumption, I don´t now?

Usually temp from the brakes and exhaust is not a problem for uprights in lower formulas or tin tops. The exception may be in highly develped cars (F1, Lemans) where for aero reasons the exhaust gases can get close.

Fatigue strength its fine for Steel.

[Jersey Tom]

-minimal weight but high stiffness  high E modulus  minimal density

IIRC you'll find that the ratio of elastic modulus to density is pretty constant among the typical engineering metals... steel, aluminum, titanium, probably magnesium as well.

[marcush.]

when chossing a material you will also need to decide on how to manufacture the component.
Would you machine it ?CNC is nowadays very convenient and with CAD you are not that far away from creating machinepaths ...
definitely a potential route for small series production .
But you could also go for a fabrication that would involve less sophisticated machining ,but the need to build jigs and lots of labor for a qualified Fabricator weldor...
Or you go for a casting ..also a possible route ...with todays RP methods investment casting as an RP method ..could be very interesting
Or you would go into mass production and do a forging....naaa ..just kidding.
but i think i have seen a Carbonfibre upright recently as well ...

At the end it`s horses for courses and you will tend to do things you know suppliers for or can produce yourself ..

[747heavy]

but i think i have seen a Carbonfibre upright recently as well ...

info

[marcush.]

I would rather not comment the girls work ..

I had in mind this one on scarbs blog:

[747heavy]

not sure I would call this band aid an "carbon upright", it probably contains more Ti then Carbon

[Belatti]

not sure I would call this band aid an "carbon upright", it probably contains more Ti then Carbon

This?

[Arunas]

not sure I would call this band aid an "carbon upright", it probably contains more Ti then Carbon

This?

[Dean4.0]

Thank you for your answers. I think i will work with this infos.