A new 3D-beam finite element including non-uniform torsion with the secondary torsion moment deformation effect

In this paper, a new 3D Timoshenko linear-elastic beam finite element including warping torsion will be presented which is suitable for analysis of spatial structures consisting of constant open and hollow structural section (HSS) beams. The analogy between the 2ndorder beam theory (with axial tension) and torsion (including warping) was used for the formulation of the equations for non-uniform torsion. The secondary torsional moment deformation effect and the shear force effect are included into the local beam finite element stiffness matrix. The warping part of the first derivative of the twist angle was considered as an additional degree of freedom at the finite element nodes. This degree of freedom represents a part of the twist angle curvature caused by the bimoment. Results of the numerical experiments are discussed, compared and evaluated. The importance of the inclusion of warping in stress-deformation analyses of closed-section beams is demostrated

Beitrag zur Geschichte plastischer Berechnungsmethoden im Stahlbau

Contribution to the history of plastic analysis methods in steel construction. Jacques Heyman (Fig. lb) has been one of the main contributors to the development of structural theory in the 20th century. After graduating he joined the famous Cambridge Team directed by John Fleetwood Baker (1901-1985) (Fig. la) that established the basis for plastic analysis of steel frame structures. Baker had worked for the Steel Structures Research Committee (SSRC) between 1928 and 1936, with the specific task of writing a rational code for elastic analysis of frames. For the first time real structures were tested. The results were surprising; elastic analysis was not suitable for predicting the actual state of the steel structure, contradicting what was believed at the time. This insight caused Baker to Change the direction of his research. In 1936 Baker traveled to Germany to attend the IABSE Conference, where he met those researchers from central Europe who, for over two decades, had been studying the elasto-plastic behaviour of steel beams. Back in the UK, he continued studying this field at Bristol University; the repeated Hermann Maier-Leibnitz's tests and started a program of tests on frames. The Second World War interrupted the work, which would continue at Cambridge once the war was over and crowned with success by the books,, The steel skeleton" [I], [2] and , Plastic design of portal frames"[3]

Grundlagen zur Methodik der Verschneidung stahlbautypischer Körper in einem CAD-System

Der Effekt des praktischen Einsatzes von CAD-Systemen im Stahlbau erschöpft sich heute weitgehend in einer Verbesserung der Qualität der Planungsunterlagen und in der Verkürzung der Bearbeitungszeiten. Dabei ist bei schwierigen individuellen Konstruktionen die Einsparung an Arbeitszeit oft nicht sehr markant gegenüber einer traditionellen Arbeitsweise. Die dreidimensionale Erfassung, Speicherung und Verarbeitung von Konstruktionsdaten im Rechner verlangt neben größeren Rechenleistungen neue Verfahren für die Behandlung dieser Daten. Die Möglichkeiten der Automatisierung stahlbautypischer Produktionsvorgänge und einer variablen, computergestützten Planung erfordern wissenschaftlich-technische Betrachtungen des Gesamtproblems. Ausgehend von den Anforderungen des Stahlbaus wird ein neues dreidimensionales Volumenmodell für den rechnergestützten Entwurf und die Konstruktion erarbeitet. Es werden grundlegende Methoden zur Problembehandlung aufgezeigt. Die Methodik basiert im wesentlichen auf der Methode der Inzidenz-Matrizen, um die Beziehungen zwischen topologischen und geometrischen Informationen eines Körpers darzustellen. Die Ermittlung der lokalen Mannigfaltigkeiten wird mit dem Euler-Polyedersatz verglichen und an Beispielen demonstriert. Eine neue Methode zur Ermittlung der lokalen Mannigfaltigkeiten wird dargestellt. Stahlbauspezifische Konstruktionen werden erzeugt und ihre Gestalt nach Anforderungen verändert. Im besonderen werden stahlbauspezifische Ausklinkungen und Verschneidungen erarbeitet und an Beispielen präsentiert

Innovation und Technologischer Wandel in Österreich

Series: Discussion Papers of the Institute for Economic Geography and GIScienc

Strength determination for band-loaded thin cylinders

Cylindrical shells are often subjected to local inward loads normal to the shell that arise over restricted zones. A simple axisymmetric example is that of the ring-loaded cylinder, in which an inward line load around the circumference causes either plasticity or buckling. The ring-loaded cylinder problem is highly relevant to shell junctions in silos, tanks and similar assemblies of shell segments. The band load is similar to the ring load in that a band of inward axisymmetric pressure is applied over a finite height: when the height is very small, the situation approaches the ring loaded case: when the height is very large, it approaches the uniformly pressurised case. This paper first thoroughly explores the two limiting cases of plastic collapse and linear bifurcation buckling, which must both be fully defined before a complete description of the non-linear and imperfection sensitive strengths of such shells can be described within the framework of the European standard for shells EN 1993-1-6 (2007). Finally, the application of the Reference Resistance Design (RRD) over the complete range of geometries for the perfect structure is shown using the outcome of the limiting cases. (EN1993-1-6, 2007; Rotter, 2016a; 2016b; Sadowski et al., 2017)

Hot-dip-zinc-coating of prefabricated structural steel components

This JRC-Scientific and Technical Report gives information from pre-normative research for methods to prevent liquid metal assisted cracking of prefabricated structural components during zinc-coating in the liquid zinc melt, that may impair the structural safety of structures in which the components are built in. This information provides a platform upon which further European design and product specifications can be developed. It may in particular affect the further developments of EN 1993, EN 1090, EN ISO 1461 and EN ISO 14713. This report gives the state-of-the-art in understanding the mechanism of liquid metal assisted cracking in the zinc bath and methods and models that may be used to avoid it. It could be a basis to propose rules for the design of steel components intended to be hot-dip-zinc-coated in such a way that the design is consistent with execution rules for hot-dip-zinc-coating. The workability of the rules proposed for all metal works and steel works that are fabricated under EN 1090 and galvanized according to the rules in this report is demonstrated by worked examples.JRC.DG.G.5-European laboratory for structural assessmen