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Currently agricultural complex is presented by diverse techniques with different manufacturing capabilities to perform various tasks. Efficiency of agricultural mechanisms and machines seriously depends on a design of their kinematic structures. In the presented study we carry out novel kinematic design of linkage-based sickle drive for actuation of combine harvester’s blades. The developed sickle drive is designed as a symmetrical planar six-bar linkage with only rotational joints. The linkage is actuated by a single pneumatic drive and allows moving blades in opposite directions with equal translations. The optimal structure of the linkage provides lightweight, reliability, speedwork, stiffness and precision for the whole drive. The study presents structural and kinematic analysis as well as numerical calculations of the proposed sickle drive. The functional capabilities of novel drive allow reducing maintenance costs and saving power.

Cutting belongs to the essential techniques in many fields of application in agricultural engineering. Cutting tools in agriculture are exposed to a high amount of abrasive wear and impact stress. Increasing the wear resistance of cuttings tools has a high significance for the efficiency and profitability of agricultural machinery. Blunt and deformed blades decrease the energy efficiency and the cutting quality. Blade failures cause machine breakdowns and increase labor and material costs. To enable a consistent and systematic optimization of the blades, a suitable testing method is necessary. Conventional field tests do not provide comparable and repeatable results. Therefore, a test method developed at the FMDauto in cooperation with the Ennepetaler Schneid- und Mähtechnik (ESM) GmbH & Co. KG is presented. The test bench provides standardized and repeatable conditions with a similar wear pattern which is found during field operations. One of the remaining challenges is a clear wear characterization. Existing analyzing methods do not consider the energy efficiency and do not determine the edge holding property clearly. In this paper, a new analyzing method based on an ellipse-fit method is introduced to rate the geometrical shape of the cutting edge and examine the wear resistance of different blades.

Common actuating principles e.g. solenoids or piezo-elements have mostly exploited their potential as electromechanical transducers. A new technology based on Dielectric Electro-active Polymers (DEAPs) enables major progress in efficiency and functionality for actuators. In order to use the advantages of this new technology in a feasible application, a silicone based DEAP diaphragm actuator was tested experimentally. Here, the mechanical properties of the fundamental parts of the DEAP diaphragm actuator, namely the stressstrain behaviour of an equibiaxially pre-stretched hyperelastic polymer and the mechanical response of a DEAP diaphragm actuator, were determined by appropriate test benches. The investigated DEAP diaphragm actuator consists of a dielectric, which corresponds to a thin elastic silicone film sandwiched between two compliant electrodes. Furthermore, DEAPs are pre-stretched, actually up to five times their in-plane dimensions, in order to improve their performance. In that context, the influence of the pre-stretched state on the actuator performance was investigated. In addition, a viscoelastic finite-element model of the electromechanical system has been developed and validated with the experimental results. The mechanical part of the DEAP diaphragm actuator was realized with an incompressible isotropic elastic model, whereas the electrical part was approximated with a circular parallel-plate capacitor. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

Soll untersucht werden, ob ein Korper auf einer rauen Unterlage haftet, oder ob er ins Rutschen gerat, mussen zunachst mithilfe der Gleichgewichtsbedingungen der Statik zwei Krafte ermittelt werden: Die Haftungskraft H, die in Richtung der Kontaktebene wirkt, und die Anpresskraft N, deren Winkungslinie senkrecht zur Kontaktebene steht. Haften ist dann gewahrleistet, wenn die Haftungskraft kleiner gleich der maximal von der Haftungsverbindung aufzubringenden Kraft Hmax ist: (4.1) mit (4.2) .

Wie im Abschnitt zu Mathcad wird auch hier nur eine kurze Einfuhrung in die Bedienung von Matlab anhand der Version 6.5 gegeben. Die Arbeitsweise von Matlab wird mithilfe von Beispielen erlautert.

Im Folgenden sollen diejenigen Informationen zum Einsatz von Mathcad gegeben werden, die den Nutzer in die Lage versetzen, die Beispielaufgaben im Text und die Ubungsaufgaben des entsprechenden Anhanges zu losen. Daruber hinaus bietet Mathcad viele weitere Moglichkeiten, die hier aus Platzgrunden nicht behandelt werden konnen. Dazu wird auf das ausfuhrliche Handbuch des Herstellers verwiesen.

Fur den in Bild 3.1 dargestellten Querschnitt ergibt sich die Normal-Spannung σ infolge der Biegemomente My und MZ zu: (3.1)

Querkraft Q(x) und Biegemoment M(x) werden am geraden Balken in der Ebene bei vorgegebenen Werten Q(0) und M(0) an der Stelle x = 0 und bei vorgegebener Streckenlast aus den Gleichgewichtsbedingungen fur den freigeschnittenen Balken ermittelt (siehe Bild 2.1).

Das Gleichgewicht eines starren Korpers im Raum (siehe Bild 1.1) wird durch die Gleichgewichtsbedingung fur alle am Korper angreifenden Krafte formuliert: (1.1) und (1.2)

Ein sehr effektives Verfahren, Verschiebungen und Verdrehungen an konkreten Punkten einer Struktur infolge deren elastischer Verformungen zu ermitteln, ist das Prinzip der virtuellen Krafte, das zur Losung der Aufgaben dieses Kapitels herangezogen wird.