It is apparent that crash management governs design for most vehicle parts. In developing the ULSAB-AVC (UltraLight Steel AutoBody-Advanced Vehicle Concept) concept, for example, roughly 80 percent of the components were influenced by requirements for crash. Regarding crashworthiness, two vehicle zones perform different roles that require different materials. One zone, the safety cage or passenger compartment, resists deformation to prevent the vehicle structure from impacting on the occupant. Another, the crumple zone, which includes the engine compartment and trunk, absorbs the energy of a front and rear crash and controls the magnitude of deceleration. High yield strength is required to resist buckling in components subjected to high axial or transverse loads. Preferred for these applications are DP 780, DP 980 and TRIP grades. To achieve the highest yield strengths possible, Mart and hotstamped boron steels often are selected. DP and TRIP steels absorb greater energy for a given strain than HSLA of equivalent yield strength. Two hydroformed, tailored tubes form the steel longitudinal rails, which are the backbone of the entire underbody and integral crash load-carrying structures for frontal-crash-energy management. These structures are made of DP steel. For most automotive parts, initial forming feasibility can be assessed with one-step forming simulations. More detailed incremental finite-element-analysis (FEA) simulations evaluate the formability of more challenging parts, including those that employ tailored blanks or the hydroforming process. For components where critical strains are predicted in the initial forming assessment, iterative changes in material or geometry are required until all components show acceptable forming behavior and become feasible to manufacture. Nine examples showcase innovative steel applications in recent vehicle platforms were shown. These vehicles feature many of the technologies and applications shown in ULSAB-AVC concepts such as high- and advanced-high-strength steels, tailored blanks and innovative design resulting in performance improvements, weight reduction and safety improvements.
Raising the bar. Revolutionary steels are helping automakers produce stronger, more fuel-efficient and cost-effective vehicle structures
Metal Forming ; 39 , 4 ; 34-42
2005
6 Seiten, 7 Tabellen
Aufsatz (Zeitschrift)
Englisch
Aufprallenergieabsorptionsvermögen , Fahrzeugbauteil , Sicherheit , Deformation , Abbremsen , Streckgrenze , Knicken , martensitischer Stahl , Werkstoffgefüge , Durchführbarkeit , Simulation , Finite-Elemente-Methode , Formbarkeit , Hydroumformen , Gewichtsverringerung , Leistungssteigerung , hochfester niedrig legierter Stahl
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