RE: aluminium (was: NEW RONIN Movie..)

[Eaton Dave <dave.eaton@minedu.govt.nz>]

another nit in this thread, but a lot of this depends on the shape and
support of the *structure* you're building, rather than on the material
itself....

in a past life i used to help build k1 canoes.  c/fibre and kevlar with
as little chop strand as possible.  light, fast and *very* strong.  it
was all down to the science of the build, and the manner in which the
mat was laid.

and as you might not know, little old nz has been building large glass
fibre boats and yachts for a long time, so the lessons have been
learned.

i imagine that the a8, nsx and other alimunum um cars are similar.  the
strength of the car comes from the manner in which the shape is
supported, rather than the material itself.

dave
'95 rs2
'90 ur-q

> Date: Thu, 10 Sep 1998 21:09:47
> From: James Marriott <marriott@pophost.micron.net>
> >> 
> >> The thing about aluminium is that you can get the _same_ strength
with
> >> less weight.  Without doing some calibrated bashing of an A8, I
> >> personally couldn't say that it would hold up better or worse than
steel
> >> to your average parking lot door bashing.
> >> 
> >Audi actually says that the tempered aluminum body panels makes the
A8
> >more dent resistant than steel panels.  This was in one of the A8
> >brochures I have.
> >
> FYI and all that, VERY FEW aluminum alloys exceed the yield strength
(on a
> volume basis) of even the weakest steel.
> 
> Ponderables:
> Aluminum is 1/3 the density of steel. Aluminum is 1/3 the stiffness
(one a
> volume basis) of steel. On a weight basis they are ~the same
stiffness.
> Aluminum costs ~3X steel on a weight basis. Indeed a pound of primo
alum
> alloy (2024-T6, 7075, etc at ~50k PSI yield strength) can be stronger
than
> a pound of crappo steel (~38k PSI YS), but you're screwed if you try
to
> weld it or form it very much, and it's pretty easy to get steel to
150k PSI
> (~Grade-5 bolt spec) or even 250 (Stainless 440A) or even 450 (music
wire).
> I think I'm getting a little tangential . . .
> 
> James
> mech eng, geek, masochist (200q and 4kq)