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BODY IN THE PROGRESS MIRROR

Let it not seem to you that this piece of hardware is much simpler than a modern engine. Creating the “right” body is no cheaper or easier.

Alexey VOROBYEV-OBUKHOV

This is dialectics: one group of researchers, sparing no means, improves the technology of manufacturing steel bodies. Another - tirelessly develops possible ways to displace iron from the car. This is the economy: some are made up of steel kings, others are aluminum and chemical magnates.

Looking back at the history of the car, it is easy to notice that this confrontation did not begin yesterday. For over a hundred years, steel has been a leader; probably now her opponents are more than ever ready for a coup. What do they offer?

First of all, of course, non-metallic materials, the tradition of which dates back to the very first machines and has since been practically uninterrupted. The first caroserie bodies were made of wood and mounted on wooden frames studded with metal. Their century was not long, but today it is instructive to recall the manufacturing technology: first, according to all the rules of carpentry (glued joints - no nails!), A solid beech or ash frame was made, which was then sheathed with wooden panels. Soon the panels became steel, they were nailed to the frame with hundreds of small studs. According to this archaic recipe, by the way, the classic English Morgan roadsters are still making. Well, who will now undertake to assert that the spatial frame is an invention of the last time? We will return to this type of supporting structure, and now we will linger on non-metallic bodies. The shortage of rolled products in Germany in the 1930s gave rise to "duroplast" - in fact, sawdust impregnated with adhesive resin, from which they were made including DKV machines. In the 50s on the "divine" "Citroen-DS19" was a plastic roof: the designers sought to lower the center of mass. In the 80s, plastic panels are already quite common - say, the fifth door of the FIAT-Tipo, the external panels of Renault-Espace and other mini-vans. Not to mention racing and “formulas”, sports cars appeared for ordinary roads with “plastic” bodies; the most famous of them is the Chevrolet Corvette. The end of the century added new unusual developments - plastics, painted in bulk, and also transparent in the necessary places. Let's say the sides with a transparent area - glass, without any seals, sealants, glue. And you do not need to paint them. This is just a godsend for cheap "folk" cars. And there are already such projects - Ecobazik from FIAT, Chrysler’s lawn mower …

The history of aluminum as a body material is somewhat poorer. Although he has many advantages, it is noticeably (2.7 times) lighter than steel and, in the usual sense, almost does not rust. Almost all engine parts were made of it, and in addition, brake cylinders, wheel disks, gearbox housings, and all kinds of decorative linings. Of the bodywork achievements, the external panels of the eternal Land Rover, riveted to the spatial frame, are remembered. Actually, the combination of “winged metal” with such a skeleton is considered mandatory today, only the latter has become much more complicated. Of the cars now produced with an aluminum body (there are not many of them yet), it is worth mentioning the exclusive Honda-NSX and the more representative Audi A8.

The difficulties of welding due to the presence of a strong oxide film on the surface are now overcome: there are inexpensive protective inert media, there is laser welding. Yes, even glue! In general, to sheathe a steel frame with aluminum panels is not a problem, but is it possible to make it from light alloys? The example of the Audi A8 and the newest A2 convincingly showed - it is possible! Look at the picture: this elegant design is actually silver. Technologically different details are highlighted here. Reds are cast, their share is 22%. Blue obtained by extrusion (extrusion), their smaller - 18%. And 60% (green color) falls on stamping from a sheet (including not shown casing). If all this was made of steel, the total mass of the body would be 40% more. Numerous computer and real crash tests showed: the aluminum body fully meets modern requirements, and from the overlay panels only the roof affects its behavior. By the way, box-shaped aluminum profiles today have learned to calculate in such a way that upon impact they are predictably compressed like accordion bellows, absorbing the calculated energy. Just what you need to protect passengers. As a result, the higher price of aluminum as a material is compensated by the opportunity to save on assembly operations: for example, the Audi A2 sidewall is one finished part from the bow to the stern!

But this is not the "last resort" of automotive fashion and technology. In pursuit of further weight reduction, the designers decided … to load the panels with load-bearing functions again. The so-called sandwich panels appeared, similar to the well-known corrugated cardboard. Between thin sheets of aluminum, an even thinner aluminum foil assembled into the corrugation is glued. Such panels are so durable that the developers are trying to apply them to partitions and flooring (the Opel-G90 concept, for example). In addition to durability and light weight, sandwich panels perfectly absorb noise, dampen vibration and protect against heat or cold.

However, there is also a “black metal” alternative: Krupp Thyssen Nirosta is promoting its new stainless alloy with chromium and manganese. With equal strength with the aluminum parts of the chassis, the nodes from it are only 1% heavier, but noticeably cheaper. Body sandwich panels made of thin stainless steel sheets with glued corrugated foil are already being tested.