Neue Loesungen mit Stahl beim Automobil-Leichtbau Abschlussbericht

The objective of the project was to investigate the weight-saving potential of steel for selected autobody components while maintaining cost levels and ensuring that there would be no lowering of current safety and comfort standards. To this end, the emphasis was placed on higher strength microalloyed, phosphorous alloyed and IF steels as well as bake hardening and dual phase steels with prescribed minimum yield points between 180 and 340 N/mm"2 used in conformity with material properties and processability. The components selected as being representative of the various requirement profiles were: the door structure of a two-door Volkswagen (VW) Polo, the front subframe of the AUDI A 4, the shock tower of the VW Polo and mounting bracket control arm of the Mercedes-Benz, C-class. The high-strength steels deemed appropriate for these components were provided in sheet thicknesses of 0.65 to 2,0 mm. The participating steel companies performed all necessary material tests on the specimen materials. Tensile tests at -40 C, room temperature and +80 C provided the characterizing mechanical property values required by the automotive industry. Notched tension and hole expansion tests, bulge tests, plotting of forming limit curves, cupping and cupping index tests afforded a good appraisal of formability. In addition, the surface chemistry and topography, roughness and friction characteristics were investigated. Fatigue strength tests as well as the determination of the dynamic characteristics (crash data) provided supplementary material data. The use of laser-welded tailored blanks for the door component proved most promising. The appropriate blanks were fabricated and the laser welding seams assessed as being very well suited to the task. (orig.)Im Rahmen des Forschungsprojektes wurde umfangreiches neues Datenmaterial ueber mechanische und technologische Eigenschaften der untersuchten Stahlsorten erarbeitet. Fuer die durchgefuehrten Konstruktionsarbeiten an den Bauteilen und Werkzeugen sowie fuer die Durchfuehrung und Planung von Abpressversuchen hat sich die Umformsimulation als sinnvolles und kostensparendes Werkzeug erwiesen. In Verbindung mit lasergeschweissten Tailored Blanks und alternativen Fuegeverfahren zum Widerstandspunktschweissen wurde fuer folgende Bauteile eine neue Konzeption und Konstruktion erarbeitet: Tuerrohbau des zweituerigen VW-Polo, Federbeinaufnahme des VW-Polo, Hilfsrahmen vorn des Audi A 4 und Konsole Querlenkerlager des Mercedes-Benz, C Klasse. Die mit entsprechend eingestellten Werkzeugen abgepressten Bauteile wurden im Praxistest auf ihre Verwendbarkeit geprueft. Es wurde gezeigt, dass eine werkstoffgerechte Bauteiloptimierung neben einer Gewichtsminderung zu einer Teilreduktion und damit zu kostenguenstigen Loesungen fuehrt. Mit dem Einsatz moderner, hoeherfester Staehle gelang unter den vorgegebenen Bedingungen der jeweils in der Serienfertigung befindlichen Fahrzeutgteile eine Gewichtsreduzierung in Hoehe 11 bis 15%. Bei voelliger Neukonstruktion ist mit Sicherheit eine weitere Gewichtsminderung umsetzbar. (orig.)SIGLEAvailable from TIB Hannover: RR 7808(244) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekEuropean Coal and Steel Community (ECSC), Brussels (Belgium)DEGerman

Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab

This document presents the initial scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) to 22 GeV. It is the result of a community effort, incorporating insights from a series of workshops conducted between March 2022 and April 2023. With a track record of over 25 years in delivering the world's most intense and precise multi-GeV electron beams, CEBAF's potential for a higher energy upgrade presents a unique opportunity for an innovative nuclear physics program, which seamlessly integrates a rich historical background with a promising future. The proposed physics program encompass a diverse range of investigations centered around the nonperturbative dynamics inherent in hadron structure and the exploration of strongly interacting systems. It builds upon the exceptional capabilities of CEBAF in high-luminosity operations, the availability of existing or planned Hall equipment, and recent advancements in accelerator technology. The proposed program cover various scientific topics, including Hadron Spectroscopy, Partonic Structure and Spin, Hadronization and Transverse Momentum, Spatial Structure, Mechanical Properties, Form Factors and Emergent Hadron Mass, Hadron-Quark Transition, and Nuclear Dynamics at Extreme Conditions, as well as QCD Confinement and Fundamental Symmetries. Each topic highlights the key measurements achievable at a 22 GeV CEBAF accelerator. Furthermore, this document outlines the significant physics outcomes and unique aspects of these programs that distinguish them from other existing or planned facilities. In summary, this document provides an exciting rationale for the energy upgrade of CEBAF to 22 GeV, outlining the transformative scientific potential that lies within reach, and the remarkable opportunities it offers for advancing our understanding of hadron physics and related fundamental phenomena