Karl-Eugen Kurrer

Eccentric vibratory mills — theory and practice

Abstract A new single-pipe vibratory mill, the eccentric vibratory mill, is introduced. It is the result of a joint development project between the Institute for Processing and Disposal Technology at the Clausthal University of Technology and Siebtechnik, Mulheim, Germany. The eccentric vibratory mill is excited on one side by means of an unbalanced-weight drive flanged directly to the grinding pipe. Unlike conventional vibratory mills with homogeneous circular vibrations, this layout causes elliptical, circular and linear vibrations. Due to a major increase of the acceleration of the individual grinding media, the throughput is increased by the factor 2. The decrease of the ratio between kerb mass and payload and the reduction of power losses due to the bearing load leads to a power consumption reduction of 50% for eccentric vibratory mills. In order to adapt the mill to specific grinding problems, the modular design was introduced. Apart from the constructive details, a mechanical analysis for an optimum dimensioning of the eccentric vibratory mill is presented. The industrial introduction is proven by examples from the fields of mineral processing, the chemical and pigment industry as well as from the field of recycling especially milling of cemented carbides.

The History of the Theory of Structures: from Arch Analysis to Computational Mechanics

Foreword by Prof. Ekkehard Ramm Preface Preface to the first, German edition The tasks and aims of a historical study of theory of structures Learning from the history of structural analysis: 11 introductory essays The first fundamental engineering science disciplines: theory of structures and applied mechanics From masonry arch to elastic arch The beginnings of a theory of structures The discipline-formation period of theory of structures From construction with iron to modern structural steelwork Member analysis conquers the third dimension: the spatial framework Reinforced concretes influence on theory of structures From classical to modern theory of structures Twelve scientific controversies in mechanics and theory of structures Perspectives for theory of structures Brief biographies Bibliography Name index Subject index

The Development of the Deformation Method

A hundred years ago, the force method formed the core of classical structural calculations. Today, the deformation method is one of the most important pillars of modern structural mechanics. The deformation method played a decisive role during the transition from classical structural calculations to modern structural mechanics in the 1950s and 1960s. The internal structure of this method was particularly suitable for implementation on computers, and today it is also used as an introduction into the basic principles of modern structural mechanics (for instance the Finite Element Method). The development of the deformation method clearly shows the dialectic interaction between the logical and the historical. Goethe’s proposition that the history of science is science itself was also a central theme for Edoardo Benvenuto. This contribution shows that the deformation method also has a genuine techno-scientific origin in its application to the problem of secondary stresses in riveted steel framework structures.

Was ist Ingenieurbaukunst

Im Rahmen des Ingenieurbaupreises 2013 von Ernst & Sohn interviewte das online-Magazin fur Ingenieure – “momentum“ – die Mitglieder der Jury (Bild 1). Die Videos gingen Ende Januar 2013 online. Nach Verbreitung des Interviews mit dem Autor dieser Zeilen schlug ihm Jorg Schlaich vor, eine schriftliche Fassung des Interviews http://momentum-magazin.de/de/ibpreis2013-kurrer/ zu veroffentlichen, was hiermit nachgeholt werden soll.

Wissenschaft in praktischer Absicht

Meilensteine der Bautechnikgeschichte: Historischer Aufsatz von Stefan Polonyi: Der Tragwerksingenieur und seine Wissenschaft mit einem Kommentar von Karl-Eugen Kurrer

Rotatable shortwave curtain antenna operable at very high wind speeds

Rotatable shortwave antennas enable broadcasters to cover target areas in any direction. This paper presents the concept and design of a rotatable curtain antenna characterized by a simple and robust design, which can be operated up to very high wind speeds. The deformation of the steel support structure is shown for typical cases of wind and ice loading, the results being obtained by FEM calculations. For the very high basic wind speed of 41 m/s (92 miles/h) the deflections of the dipole and reflector curtains are calculated and subsequently the RF characteristics for this situation. It is found that the influence of wind on the input impedance and the radiation patterns is remarkably low.