ok.......so the Fiero has a space frame. Cool.......

....uhhhh, whats a space frame??

I hear terms like unibody cars ( which I understand) But then I thought that monocoques was the exact same thing. Some say they are not.

.....then things got real weird when I went on a Corvette forum and they were arguing that the Corvette is a Body on Frame car. Hmmmmmm like a truck???

Oh and lets not forget Tubular frames, like the Ferrari F40!! Im assuming this would be the frame of a Dune Buggy???
OK, I need help. please please please can someone define each type of frame structure to me. I though that there was really only two for the logest time. Body on frame (truck) and unibody (car).

you need history of the automobile 101...
body on frame comes from the horse and buggy era, as all vehicles then used a frame with a body or box added to it.
Early cars had massive frames in them. Some were quite mind boggling as to how massive and heavy just the frame was.
Unibody construction was a weight and material saving idea of the sixties, and cars and trucks have been built that way, while heavy duty trucks kept the frame and body construction for strength.
The space frame is a unique idea where you have interior and exterior panels mounted on a frame in the space in between the panels...
Tubular frames have been used for all kinds of vehicles, especially where you wanted to build in safety cages into the frame, like you said, dune buggies, but also dragsters, and funny cars.

quote Originally posted by Space Frame Wiki: In architecture and structural engineering, a space frame or space structure is a truss-like, lightweight rigid structure constructed from interlocking struts in a geometric pattern. Space frames can be used to span large areas with few interior supports. Like the truss, a space frame is strong because of the inherent rigidity of the triangle; flexing loads (bending moments) are transmitted as tension and compression loads along the length of each strut. Overview Simplified space frame roof with the half-octahedron highlighted in blue The simplest form of space frame is a horizontal slab of interlocking square pyramids and tetrahedra built from aluminium or tubular steel struts. In many ways this looks like the horizontal jib of a tower crane repeated many times to make it wider. A stronger form is composed of interlocking tetrahedra in which all the struts have unit length. More technically this is referred to as an isotropic vector matrix or in a single unit width an octet truss. More complex variations change the lengths of the struts to curve the overall structure or may incorporate other geometrical shapes. History Space frames were independently developed by Alexander Graham Bell around 1900 and Buckminster Fuller in the 1950s. Bell's interest was primarily in using them to make rigid frames for nautical and aeronautical engineering, with the tetrahedral truss being one of his inventions. However few of his designs were realised. Buckminster Fuller's focus was architectural structures; his work had greater influence. Vehicles Cars Spaceframes are sometimes used in the chassis designs of automobiles and motorcycles. In both a spaceframe and a tube-frame chassis, the suspension, engine, and body panels are attached to a skeletal frame of tubes, and the body panels have little or no structural function. By contrast, in a unibody or monocoque design, the body serves as part of the structure. Tube-frame chassis pre-date spaceframe chassis and are a development of the earlier ladder chassis. The advantage of using tubes rather than the previous open channel sections is that they resist torsional forces better. Some tube chassis were little more than a ladder chassis made with two large diameter tubes, or even a single tube as a backbone chassis. Although many tubular chassis developed additional tubes and were even described as "spaceframes", their design was rarely correctly stressed as a spaceframe and they behaved mechanically as a tube ladder chassis, with additional brackets to support the attached components, suspension, engine etc. The distinction of the true spaceframe is that all the forces in each strut are either tensile or compression, never bending.[1] Although these additional tubes did carry some extra load, they were rarely diagonalised into a rigid spaceframe.[1] The first true spaceframe chassis were produced in the 1930s by designers such as Buckminster Fuller and William Stout (the Dymaxion and the Stout Scarab) who understood the theory of the true spaceframe from either architecture or aircraft design.[2] The first racing car to attempt a spaceframe was the Cisitalia D46 of 1946.[2] This used two small diameter tubes along each side, but they were spaced apart by vertical smaller tubes, and so were not diagonalised in any plane. A year later, Porsche designed their Type 360 for Cisitalia. As this included diagonal tubes, it can be considered the first true spaceframe.[2] The Maserati Tipo 61 of 1959 (Birdcage) is often thought of as the first but in 1949 Dr. Robert Eberan-Eberhorst designed the Jowett Jupiter exhibited at the London Motor Show in 1949 and taking a class win at the 1950 Le Mans 24hr. Later the small British car manufacturers developed the concept TVR produced an alloy-bodied two seater on a multi tubular chassis, which appeared in 1949. Colin Chapman of Lotus introduced his first 'production' car, the Mark VI, in 1952. This was influenced by the Jaguar C-Type chassis, another with four tubes of two different diameters, separated by narrower tubes. Chapman reduced the main tube diameter for the lighter Lotus, but did not reduce the minor tubes any further, possibly because he considered that this would appear flimsy to buyers.[1] Although widely described as a spaceframe, Lotus did not build a true spaceframe chassis until the Mark VIII, with the influence of other designers, with experience from the aircraft industry.[1] Other notable examples of tube-frame cars include the, Audi R8, Ferrari 360, Lamborghini Gallardo, and Mercedes-Benz SLS AMG. A drawback of the spaceframe chassis is that it encloses much of the working volume of the car and can make access for both the driver and to the engine difficult. Some spaceframes have been designed with removable sections, joined by bolted pin joints. Such a structure had already been used around the engine of the Lotus Mark III.[3] Although somewhat inconvenient, an advantage of the spaceframe is that the same lack of bending forces in the tubes that allow it to be modelled as a pin-jointed structure also means that such a removable section need not reduce the strength of the assembled frame. Motorcycles 2006 Ducati Paul Smart 1000LE Italian motorbike manufacturer Ducati extensively uses tube frame chassis on its models. Space frames have also been used in bicycles, such as those designed by Alex Moulton. [edit]Design methods Space frames are typically designed using a rigidity matrix. The special characteristic of the stiffness matrix in an architectural space frame is the independence of the angular factors. If the joints are sufficiently rigid, the angular deflections can be neglected, simplifying the calculations.

Almost all you would like to know about space frames.

Body-On-Frame:



Uni-Body (Three of them actually):



SpaceFrame:



And... a partial Uni-body / Body-on-Frame (basically, early Uni-Body that's really still kind of a Body-on-Frame):

This is a space frame, the famous Maserati Tipo 61 (a.k.a. "Birdcage") race car:



The distinguishing feature of true space frames is that all structural components are loaded either in pure tension or pure compression ... no bending or shear. On this basis, the Fiero cannot be considered a "true" space frame, since there will always be some shear load carried in the sheet steel panels. The Fiero is indeed a "pseudo" space frame, comprising a structural central core with non-structural body panels, drivetrain, and suspension components attached.



You can kinda' see how the space frame idea evolved from the Maserati Tipo 61 into semi-monocoque structures. Just keep making the tubes smaller and thinner, which means you have to have more and more of them, until eventually the tubes flatten and begin to merge into a structure made up almost entirely of thin sheets, perhaps with large lightening holes where the loads are small.

[This message has been edited by Marvin McInnis (edited 04-18-2013).]

Corvette frame 63-83







1984:




"The C4 made history as the first unit-construction Corvette, using this sturdy "birdcage" or "uniframe" structure
The old perimeter-type ladder frame was replaced by a steel backbone design not unlike that pioneered by England's Lotus. In the Corvette, the "spine" took the form of a C-section beam rigidly connected to the differential and carrying the driveshaft. This arrangement reduced weight and opened up more cockpit room by eliminating the transmission and differential crossmembers, and by permitting the exhaust system to be run beneath the driveshaft instead of alongside it.

Welded to the backbone was what Chevy called an "integral perimeter-birdcage unitized structure" or "uniframe," making the new model the first Corvette to employ modern unit construction instead of the old body-on-frame configuration. The "birdcage" formed the windshield and door frames, lower A-pillar extensions, rocker panels, rear cockpit wall, and front subframe. It also included a "hoop" above and behind the cockpit, both for additional rigidity and as a hinge point for the lift-up rear window. Galvanized inside and out for corrosion resistance, this structure effectively comprised a skeleton onto which the fiberglass outer panels would attach. Completing the basic assembly were an aluminized bolt-on front suspension carrier and a bolt-on extension for the back bumper."http://auto.howstuffworks.com/1984-corvette1.htm

(much like the Fiero)

[This message has been edited by 2.5 (edited 04-19-2013).]

I love the huge u-joint axles on the C3... Regardless of the primitive construction I still love 'em...



Yes, even with the luggage rack...

------------------

67 Camaro Unibody, the body is part of the structure, in this image is all the "frame" that there is. The front and rear "subframes" are usually joined together with aftermarket parts if you are run major power and cornering these days.

[This message has been edited by 2.5 (edited 04-19-2013).]

quote Originally posted by 2.5: The old perimeter-type ladder frame was replaced by a steel backbone design not unlike that pioneered by England's Lotus.

Another instance of GM "Design by Lotus"? Lotus first used a backbone frame design in the 1962 Elan:



Porsche also used a semi-backbone frame design in the 928 (1978).

quote Originally posted by carbon: I love the huge u-joint axles on the C3...

That's because the half-shafts also served as the lateral control links ... as Lotus had used for their much lighter and less powerful Elite and Elan models.

[This message has been edited by Marvin McInnis (edited 04-19-2013).]

quote Originally posted by Marvin McInnis: Another instance of GM "Design by Lotus"?

Those Lotus designers have some good things going

So would you say its more accurate to call the Fiero a "uniframe" ?

[This message has been edited by 2.5 (edited 04-19-2013).]

The VERY uttermost basic idea behind a space frame is it can be driven with ALL the body panels removed. With a Fiero, you can remove every body panel on the car and drive just the space frame.

On vehicles that are usually referred to as "uni-body" structure, they usually cannot be driven with all the panels removed because all the panels CANNOT be removed. For instance, on many vehicles, the rear quarter panel area acts as a structural unit for the car. You typically cannot remove this area because it will compromise the vehicle's ability to be driven.

A body on frame can be thought of as a body and partial chassis structure that can be removed, leaving a separate rolling chassis or "under structure". A good example of this is a DeLorean. The actually chassis with the suspension pieces can be separated from the body chassis structure that holds the body panels.

quote Originally posted by Marvin McInnis: That's because the half-shafts also served as the lateral control links ... as Lotus had used for their much lighter and less powerful Elite and Elan models.

That I did not know...

wow.......you guys are the best!!

What an awesome tutorial! Just reading these posts, I think these guys must have degrees in "space frame technology". Thanks for the info! It was a lot, but you made it understandable.