P 111 - Cold-formed, lightweight steel profiles as structural components in structural engineering applications

P 110 - Measures to improve utilisation and increase the load-bearing capacity of cold profiles The research "Measures to improve the utilisation and increase the load-bearing capacity of cold-formed sections" aims to utilise the load-bearing reserves not covered by the simplified verification and the increases in load-bearing capacity that can be achieved by design measures. The report is divided into three parts, the contents of which are summarised below. Part 1 deals with the following topics: - Solution of the branching problem " lateral-torsional buckling with profile deformation" for thin-walled but not buckling-prone top-hat and C-profiles. A Fortran programme system is available. - Quantification of the warping stress effect of truss nodes. - Constructive measures to increase the vault leg tension effect. - Model tests to validate the theoretical findings. - Development of a lateral-torsional buckling analysis suitable for manual calculation for members supported under arch loads with detailed calculation examples. Part 2 deals with the problems: - Solution of the branching problem "lateral-torsional buckling with section deformation" for single or frame members stiffened with tie plates. A Fortran programme system is also available here. - Carrying out model tests a) Torsion tests b) Bending-torsional buckling tests 2to check the theoretical approaches. - A simplified verification method suitable for manual calculation is proposed for single bars with hat or C-profile cross-sections. Part 3 analyses the longitudinal stiffening of plates by beads. The common calculation model - beams on elastic bedding as buckling bars - is compared with precise calculations. The difficulties in determining the stiffness values are shown and curve tables for the buckling loads of the beads are given for total and partial buckling. The appendix contains curve tables for C and hat profiles, from which all cross-section values required for the lateral-torsional buckling analysis with profile deformation can be read. The application is shown in a calculation example. This research has made a remarkable contribution to the mathematical determination of the load-bearing capacity of open cold-formed profiles. In addition, design measures have been shown that lead to an increase in the load-bearing capacity of cold-formed profiles. The design aids provided lead to a significant simplification of the stability analyses and set priorities for the applying engineer. While the investigations in Parts 1 and 2 were able to lead to a simple design method that can be used in practice, the design concept in Part 3 has not yet been fully clarified to the point of simple methods for practical application because the time available was not sufficient. The work was funded by the Federal Ministry of Research and Technology (BMFT) and was supervised by Kernforschungsanlage Jülich GmbH (KFA) as the project sponsor for the raw materials research programme. The work was carried out at the Technical University of Darmstadt, Institute for Statics, Prof. Dr.-Ing. The administrative management of the project was the responsibility of the Studiengesellschaft für Anwendungstechnik von Eisen und Stahl e.V. STUDIENGESELLSCHAFT FÜR ANWENDUNGSTECHNIK VON EISEN UND STAHL e.V. Publication: 1986 Authors: Prof. Dr.-Ing. R. Schardt, Dipl.-Ing. M. Hanf, Dipl.-Ing. Chr. Schardt

P 100 - Development of characteristic values for the production of cold rolled profiles from the point of view of economical production of dimensionally accurate profiles Cold profiling using the roll forming process is a forming process that has been used industrially for over half a century. It allows the production of cold-formed profiles with consistent and high dimensional accuracy, some with sharp-edged bends, many curved sections, complicated double folds, with - if desired - targeted work hardening of the starting material and finally the combination of profile shaping with further processing steps such as punching, beading and bending. Although the diverse requirements and the general technical development of mechanical engineering have led to a wide variety of roll forming systems over the course of time, the technology of roll forming is still largely based on practical experience. This applies both to the dimensioning of production facilities and to the design of forming tools. This unsatisfactory situation can probably be explained essentially by the fact that the entire process - in addition to the rather difficult geometric relationships of forming - is governed by numerous working conditions which influence each other. For this reason, the Technical Committee of the German Cold Forming Association has been working closely with a well-known plant manufacturer for several years on the development and dimensioning of a machine and drive concept for research purposes. A machine and control technology solution was developed and realised which for the first time makes it possible to empirically investigate the interactions between the parameters of the production process and the properties of the product in a reproducible manner. This research work was carried out on behalf of the Studiengesellschaft für Anwendungstechnik von Eisen und Stahl e.V. by Prof. Dr.-Ing. D. Schmoeckel, Institute for Forming Technology at Darmstadt Technical University. In addition to confirming some of the results of earlier investigations, new findings of practical relevance were obtained. This applies in particular to the experiments on slip reduction, which resulted in a drastic saving in the energy used, and on the relationship between the quality of the finished product and the selected forming strategy. These results represent a step towards a better understanding of the complex manufacturing process, but at the same time demonstrate the need for further intensive efforts to conduct in-depth research into roll forming technology. The research project was funded by the Federal Ministry of Research and Technology (BMFT) and was supervised by Kernforschungsanlage Jülich GmbH (KFA) as the project sponsor for the raw materials research programme. STUDIENGESELLSCHAFT FÜR ANWENDUNGSTECHNIK VON EISEN UND STAHL e.V. Publication: 1986 Authors: Prof. Dr.-Ing. D. Schmoeckel, Dipl.-Wirtsch.-Ing. U. Eichler