As the next-generation Mercedes-AMG SL roadster undergoes testing through its various stages, the manufacturer has released images of the bodyshell that will be the base of the car that is a clean sheet design. Not a single section was carried over from the outgoing R231-generation SL, says Mercedes-AMG, and neither were any taken from the AMG GT Roadster it is intended to replace.
“On the one hand we have managed to reconcile the high package demands, while on the other we have been able to achieve excellent rigidity values in all areas in conjunction with a favourable weight, so providing the basis for agile driving dynamics and exceptional comfort,” said Mercedes-AMG chief technical officer Jochen Hermann.
Along with its return to using a fabric roof, the upcoming Mercedes-AMG SL will also feature a 2+2 seating configuration, which presented the development team with new challenges in terms of complexity, according to the manufacturer. The R232 is being developed with a composition of aluminium, steel, magnesium and composite fibres in order to attain the highest possible level of rigidity at a relatively low weight.
Rollover protection is paramount in open-top vehicles, and here the windscreen frame of the R232 SL is made of high-strength, hot-formed tubular steel, and this is paired with a pop-up rollover structure behind the rear seats – similar to that offered in previous generations of the SL.
Nodal points along the bodyshell, where forces come together or where large forces have to be transferred, employ cast aluminium components, and these are used as they have the advantage of of enabling the specific discharge of forces, says Mercedes-AMG.
Wall thicknesses can then be varied according to the loads encountered, for greater rigidity in areas where required, such as at chassis connections. The walls of the aluminium components are only as thick as they need to be, which enables weight savings in areas subject to lower forces, the firm says.
These measures enable a torsional stiffness that is increased by 18% compared to the outgoing SL, while tranverse rigidity is 50% greater and longitudinal rigidity is 40% greater than those of the AMG GT Roadster. The increased rigidity overall offers a better base for offering more precise handling and better agility, and the bare bodyshell without doors, bonnet, bootlid and other assembly parts weighs around 270 kg.
The entire vehicle concept has been developed with the lowest possible centre of gravity in mind, where the bodyshell connection points to the powertrain and axles, as well as rigidity-relevant sections of the bodyshell are situation as low in the body as possible.
As the aforementioned connection points have to be more rigid and use more material as a result, so these heavier sections are located lower in the car. Examples of these are the connections between the front and rear sections as well as the occupant safety cell.
Throughout the R232 SL’s bodyshell, joining techniques used include MIG (metal inert gas) welding, laser welding, punch riveting, blind riveting, MIG soldering, glued seams and flow hole bolts, and the new bodyshell meets all internal crash requirements, says Mercedes-AMG.
Pre-development of the bodyshell was done in three months, while it took less than three years from the commissioning of the new SL to the release of the new model series, says the manufacturer, adding that the structural verification vehicle received the top internal rating in its first real-life crash test.
Production of the R232 Mercedes-SL will take place at the Bremen facility, which also produced its R231 predecessor. During development, our spy photographer sources have sighted the upcoming model in both six- and eight-cylinder versions, the latter possibly with an electrified powertrain offering in the region of 800 hp and 1,000 Nm of torque.
GALLERY: R232 Mercedes-AMG SL, eight-cylinder spyshots
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