pressurized tubular chassis

Im not thinking of putting in very very high pressure air.
I was thinking maybe a few hundred PSI of gas would still help
strengthen the structure a bit.
Although the added strength is minimal, that's still better than
nothing.
It could add to resistance against bending/flexing.


I'm not planning to use air.... considering nitrogen or CO2.








On Nov 7, 9:08 pm, "Joseph Gliebe" wrote:
> You may find pressurizing your chassis would introduce more problems than
> strength. The pressure you would need would be very very high to even be
> measureable. If you used air, the oxidation process in your chassis would
> be enhanced (not a good thing).
>
> In other words, I am sure many other engineers will tell you the results
> would be insignificant and probably not measureable....Besides why introduce
> more stress on the tubing by pressurizing it.
>
> Joe
> Structural, nuclear engineer
>
> wrote in message
>
>
>
> > Hi!
> > I am building a tubular chassis and I was thinking if pressurizing
> > (high pressure) the inside of the chassis with air would help add
> > strength to it?
 >> Stay informed about: pressurized tubular chassis 

wrote:
> Im not thinking of putting in very very high pressure air.
> I was thinking maybe a few hundred PSI of gas would still help
> strengthen the structure a bit.
> Although the added strength is minimal, that's still better than
> nothing.
> It could add to resistance against bending/flexing.
>
>
> I'm not planning to use air.... considering nitrogen or CO2.
>

The only thing it will help prevent is buckling-mode failure - and
that's almost never a factor in non-collision situations. It increases
static tensile stress and, unless you're using Kevlar tubing, will have
negative effect on the longevity of the chassis (although at the
pressure you're proposing, it will have negligible effect).

Filling the tubes with argon or nitrogen will help prevent corrosion a
little though.
 >> Stay informed about: pressurized tubular chassis 

Agree with everything said so far.
Looking at the big picture, not worth it, especially when you consider
sealing the gas in. If no benefit is gained from doing it, why go through
the expense.

Joe
"Bob P" wrote in message

> wrote:
>> Im not thinking of putting in very very high pressure air.
>> I was thinking maybe a few hundred PSI of gas would still help
>> strengthen the structure a bit.
>> Although the added strength is minimal, that's still better than
>> nothing.
>> It could add to resistance against bending/flexing.
>>
>>
>> I'm not planning to use air.... considering nitrogen or CO2.
>>
>
> The only thing it will help prevent is buckling-mode failure - and that's
> almost never a factor in non-collision situations. It increases static
> tensile stress and, unless you're using Kevlar tubing, will have negative
> effect on the longevity of the chassis (although at the pressure you're
> proposing, it will have negligible effect).
>
> Filling the tubes with argon or nitrogen will help prevent corrosion a
> little though.
 >> Stay informed about: pressurized tubular chassis 

Doubtful. You will be simply adding stresses due to the pressurisation to
whatever stresses are imposed by dead & live loads.
Also at the sorts of pressure you are contemplating (Iassume around 80 PSI)
The stresses due to pressure will be negligable.
I seem to recall that Rolls Royce many years ago experimented with
pressureised nitrogen chasssis members, the idea was to ensure internal
corrosion could not proceed.
Remember that if youn do this maybe just to satisfy your desire to do
something different that a complete seal will need to be maintained so
drilling to makeb attachments (thought of afterwards) will not be possible.
Pete
wrote in message

> Hi!
> I am building a tubular chassis and I was thinking if pressurizing
> (high pressure) the inside of the chassis with air would help add
> strength to it?
>
 >> Stay informed about: pressurized tubular chassis 

wrote:
> Hi!
> I am building a tubular chassis and I was thinking if pressurizing
> (high pressure) the inside of the chassis with air would help add
> strength to it?
>

Porsche did exactly this on the 908, but for very different reasons. The
tubular frame was prone to cracking, so they pressurised it and checked
with it using a tyre pressure gauge. Low or no pressure meant a crack
had developed somewhere.......

--

Chris

I am not young enough to know everything.
Oscar Wilde (1854 - 1900)
 >> Stay informed about: pressurized tubular chassis 

Why not Hydrogen?

"mower man" <"chrislovett <nospam> wrote in message

> wrote:
>> Hi!
>> I am building a tubular chassis and I was thinking if pressurizing
>> (high pressure) the inside of the chassis with air would help add
>> strength to it?
>>
>
> Porsche did exactly this on the 908, but for very different reasons. The
> tubular frame was prone to cracking, so they pressurised it and checked
> with it using a tyre pressure gauge. Low or no pressure meant a crack had
> developed somewhere.......
>
> --
>
> Chris
>
> I am not young enough to know everything.
> Oscar Wilde (1854 - 1900)
 >> Stay informed about: pressurized tubular chassis