After investigation of several alternative materials and body constructions including high strength steels in conventional unitized body construction, aluminum unitized body construction, aluminum tubular space frame construction, and a composite intensive construction, a hybrid design with a primarily die-cast magnesium structure utilizing sheet aluminum floor pans, aluminum crash rails, and composite exterior Class A panels was derived. The following comparisons are made between the lightweight body concept and the conventional steel body-in-white. Reduced part count of nearly 80% - 44 vs. 204. Total body in white weight (including composite exterior panels) reduced by 40% - 270 kg vs. 445 kg. Body structure weight reduced by 43% - 181 kg vs. 318 kg. Bending frequency remained constant at 36 Hz. Torsional frequency improved by more than 20% to 45 Hz. Reduced investment cost of 28%, Increased variable cost of less than 2%, Met or exceeded all NVH and energy management goals. The prototype body weighed more than predicted by ca. 35 kg. Detailed analysis of the prototype build process revealed that the sand castings exceeded their design weights by a total of 10 kg (ca.10%) due to inability to cast all of the parts as thin as the production intent diecastings. While additional research and development work would be required to fully validate the concept for high volnm production, the work conducted on this project indicates that a lightweight body structure with extensive use of large thin-wall magnesium die castings can meet all current structural and energy management requirements at a competitive cost to conventional steel body structures while achieving significant weight savings.
A lightweight automobile body concept featuring ultra-large, thin-wall structural magnesium castings
Ein Leichtbau-Konzept für die Automobilkarosserie verwirklicht durch ultragroße dünnwandige Magnesiumgussteile
2007
9 Seiten, 20 Bilder, 18 Quellen
Conference paper
English
Robustness of Large Thin Wall Magnesium Die Castings for Crash Applications
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British Library Conference Proceedings | 2004
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