Question on monocoque chassis...

Can anyone tell me the reason monocoque chassis have a lot of
irregular "planes" such as the floor? I mean they're not usually flat
even though they can be flat. Most parts have curves.... seems to be
stamped.

I'm studying welding and fiberglass fabrication and I'm planning to
build a monocoque chassis.
Been trying to study monocoque chassis from different cars.

On Mon, 30 Jul 2007 09:00:31 -0700, lethaldriver wrote:

> Can anyone tell me the reason monocoque chassis have a lot of irregular
> "planes" such as the floor? I mean they're not usually flat even though
> they can be flat. Most parts have curves.... seems to be stamped.
>
> I'm studying welding and fiberglass fabrication and I'm planning to build
> a monocoque chassis.
> Been trying to study monocoque chassis from different cars.


Because convolution adds strength. If it were flat it would be weaker,
Look at stamped steel, or even courregated cardboard.

"Hachiroku ãƒ�ãƒ�ãƒ*ク" > wrote in message news:Cfrri.6393
> Because convolution adds strength. If it were flat it would be weaker,
> Look at stamped steel, or even courregated cardboard.

Exactly.... in the same vein that an egg is not a cube, except that the
chicken
would have a heck of a time with a cubic egg.

Curved surfaces often convey strength and rigidity that flat surfaces
cannot.

Open tubes are also stronger than rods containing the same amount of metal.

This is a study, not an exercise in logic.

Which has better strength to weight ratio? a monocoque or a tubular,
spaceframe chassis?





On Jul 31, 10:16 pm, (Scott Dorsey) wrote:
> > wrote:
> >Can anyone tell me the reason monocoque chassis have a lot of
> >irregular "planes" such as the floor? I mean they're not usually flat
> >even though they can be flat. Most parts have curves.... seems to be
> >stamped.
>
> It increases strength in one direction. Take a piece of corrugated iron
> and notice how much harder it is to bend in one direction than in the
> other. The corrugations stiffen it.
> --scott
> --
> "C'est un Nagra. C'est suisse, et tres, tres precis."

On Aug 2, 10:06 am, wrote:
> Which has better strength to weight ratio? a monocoque or a tubular,
> spaceframe chassis?
>
> On Jul 31, 10:16 pm, (Scott Dorsey) wrote:
>
>
>
> > > wrote:
> > >Can anyone tell me the reason monocoque chassis have a lot of
> > >irregular "planes" such as the floor? I mean they're not usually flat
> > >even though they can be flat. Most parts have curves.... seems to be
> > >stamped.
>
> > It increases strength in one direction. Take a piece of corrugated iron
> > and notice how much harder it is to bend in one direction than in the
> > other. The corrugations stiffen it.
> > --scott
> > --
> > "C'est un Nagra. C'est suisse, et tres, tres precis."- Hide quoted text -
>
> - Show quoted text -

monocoque. you can see the evolution of the spaceframe chassis in
something like the maserati birdcage; to get better strength/weight
they make more, tinier tubes. the ultimate end when you continue in
this direction, is the monocoque.

wrote in article
.com>...
> Which has better strength to weight ratio? a monocoque or a tubular,
> spaceframe chassis?
>
>
>


Your question is much too generic and vague for such a complex issue.

It all depends on the design.

There are instances when one is better, and instances where the other is
better.

Monocoque - as in race car - is often a combination of bulkheads AND space
frame, along with stressed skin, so it isn't REALLY much different from
space frame design in many senses.

Your original question suggests that you are using the term "monocoque" as
a synonym to "unibody". That is an incorrect usage.

Monocoque is a form of race car chassis design - and doesn't usually
include floor panels with numerous bends to add strength. Such panels would
make accurate race car chassis repair a nightmare.

Straightforward, simple panels are preferred in race car design.

A space frame with bulkheads covered by a stressed skin is the norm for
monocoque chassis.

Most unibody cars do not have a structure that could be considered a
"bulkhead" in the monocoque sense, nor do they have space frames to which
bulkheads are attached.

I doubt if Google would help you much. Perhaps you ought to spend some time
in a technical/engineering library studying the issues.

wrote:
> Which has better strength to weight ratio? a monocoque or a tubular,
> spaceframe chassis?
>
>
>
>
Why don't you buy some of Carrol Smith's books? They will answer questions
you haven't even thought of yet.

On Mon, 30 Jul 2007 23:16:39 +0000, hls wrote:

>
> "Hachiroku ãƒ�ãƒ�ãƒ*ク" > wrote in message
> news:Cfrri.6393
>> Because convolution adds strength. If it were flat it would be weaker,
>> Look at stamped steel, or even courregated cardboard.
>
> Exactly.... in the same vein that an egg is not a cube, except that the
> chicken
> would have a heck of a time with a cubic egg.
>
> Curved surfaces often convey strength and rigidity that flat surfaces
> cannot.
>
> Open tubes are also stronger than rods containing the same amount of
> metal.
>
> This is a study, not an exercise in logic.


Right. An open rod has two 'bearing' surfaces, the inside surface and the
outside surface.

Monocoques aren't only for race cars. Most the production cars
nowadays have monocoque chassis.
These cars are have monocoque chassis but don't necessarily have any
steel tubing to help support the chassis.

The monocoques you're talking about are probably the carbon fiber
monocoque chassis used in F1 cars.

How do you make "stressed skin"? Do you just make sure that the
"skin"/body is well bonded onto the chassis to make it stressed skin?





On Aug 3, 12:13 am, "*" > wrote:
> wrote in article
> .com>...
>
> > Which has better strength to weight ratio? a monocoque or a tubular,
> > spaceframe chassis?
>
> Your question is much too generic and vague for such a complex issue.
>
> It all depends on the design.
>
> There are instances when one is better, and instances where the other is
> better.
>
> Monocoque - as in race car - is often a combination of bulkheads AND space
> frame, along with stressed skin, so it isn't REALLY much different from
> space frame design in many senses.
>
> Your original question suggests that you are using the term "monocoque" as
> a synonym to "unibody". That is an incorrect usage.
>
> Monocoque is a form of race car chassis design - and doesn't usually
> include floor panels with numerous bends to add strength. Such panels would
> make accurate race car chassis repair a nightmare.
>
> Straightforward, simple panels are preferred in race car design.
>
> A space frame with bulkheads covered by a stressed skin is the norm for
> monocoque chassis.
>
> Most unibody cars do not have a structure that could be considered a
> "bulkhead" in the monocoque sense, nor do they have space frames to which
> bulkheads are attached.
>
> I doubt if Google would help you much. Perhaps you ought to spend some time
> in a technical/engineering library studying the issues.

wrote:
> Monocoques aren't only for race cars. Most the production cars
> nowadays have monocoque chassis.
> These cars are have monocoque chassis but don't necessarily have any
> steel tubing to help support the chassis.
>
> The monocoques you're talking about are probably the carbon fiber
> monocoque chassis used in F1 cars.
>
> How do you make "stressed skin"? Do you just make sure that the
> "skin"/body is well bonded onto the chassis to make it stressed skin?
>

A stressed skin is simple. All it takes to make it is to use the skin to
also support part of the load as well as itself. Take a look at most
sport bikes and you will see that they use the engine as a stressed part
of the frame. Same ides with a stressed skin. On an auto you could make
the roof a stressed skin by making it a structural member which holds
the vehicle in shape, like 99% of the unibody vehicles out there today.
Cut the roof off and they fold up.

--
Steve W.