Fixed centrode of the compliant isosceles slider-crank mechanism

Compliant mechanisms gain some or all of their mobility from the relative flexibility of their joints rather than from rigid-body joints only. Compliant mechanisms can provide many benefits in the solution of design problems: they have less wear, weight, noise and backlash than their rigid-body counterparts. They can be manufactured from one piece of material, and therefore they are suitable to be applied in micromechanics. On the other hand, nonlinearities introduced by the large deflection of elastic segments further complicate the analysis of compliant mechanisms. This paper takes into consideration the isosceles slider–crank mechanism and its compliant counterpart mechanism, being developed on the basis of the rigid-body mechanism. The design of the compliant slider-crank mechanism with notch joints (circular flexure hinges) has been shown in this paper. The methods of determining of the "fixed centrode" has been also presented for the compliant isosceles slider–crank mechanism. The aim of the paper is to suggest a method of determining of the "fixed centrode" of the compliant mechanism.Nachgiebige Mechanismen bekommen ihre Beweglichkeit von ihre elastischen Gelenken. Sie können aus einem Stück hergestellt werden und deswegen sind sie geeignet für die Anwendungen in der Mikromechanik. Die nachgiebige Mechanismen haben viele Vorteile. Sie sind leicht, spielfrei, reibungsarm, verschleißarm (es gibt nur innere Reibung) und geräuscharm. Anderseits, große nichlineare Verformungen von elastischen Segmenten führen die Schwierigkeiten in Analyseverfahren von nachgiebiger Mechanismen ein. Dieser Beitrag befasst sich mit der gleichschenkligen Schubkurbel und der nachgiebigen Kopie von gleichschenkligen Schubkurbel. In diesem Beitrag wird die nachgiebige gleichschenklige Schubkurbel mit Kerbgelenken entworfen und die "Rastpolbahn" des geführten Segments ermittelt. Das Ziel des Beitrags ist die Vorgehenssweise für die Bestimmung der "Rastpolbahn" bei den nachgiebigen Mechanismen vorzuschlagen

GUIDING ACCURACY OF THE WATT COMPLIANT COGNATE MECHANISMS

In kinematics, cognate linkages are those that ensure the same input-output relationship or coupler curve geometry, while being dimensionally dissimilar. Compliant mechanisms gain some or all of their mobility from the relative flexibility of their joints rather than from the rigid-body joints only, which is the case with classical mechanisms. In this paper the guiding accuracy of the compliant cognate Watt four-bar linkages has been presented. The compliant cognate mechanisms have been developed as the counterparts of the rigid-body Watt mechanism, where the coupler point can be guided on an approximate rectilinear path. The guiding accuracy of the "coupler" point on the path segment (minimal deviation between exact rectilinear and realized path) has been calculated for the new-designed compliant mechanisms

Modelling of a compliant Scott-Russel mechanism with small length flexural pivots

This paper takes into consideration the Scott-Russel mechanism (the isosceles slider–crank mechanism) and its compliant counterpart mechanism, being developed on the basis of the rigid-body mechanism. Various types of this compliant Scott-Russel mechanism with small length flexural pivots and various geometry parameters of these joints, as well as various rigidity ratios of the relative rigid and relative elastic sections of the mechanism, are researched. The aim of the paper is to suggest optimal parameters, as well as the motion range of this compliant mechanism, in order to obtain the minimal deviation (the minimal difference between the realized path of the "coupler" point and the exact straight line). Finally, the mobility of the developed compliant mechanism, that is, the limit positions of the links determined by the maximal bending stress value, is examined

Wind towers - design of flange ring connection

Today, wind power is second largest available renewable resource of energy, with 870 TW (terawatts). Large wind farms, with hundreds of wind towers are big opportunity for steel production industry. Designers and manufacturers of wind towers pay special attention on every single detail, always looking for some new solutions, trying to reduce price of wind towers. Some of the most interesting design and manufacturing details are connections used to assemble sections of tubular steel towers supporting wind turbins. There is traditional and actually more used flange ring connection and on the other side, as a new proposal which is used more and more, friction connection. In this paper theoretic basis of design of flange ring connection of wind towers is give

Design of class 4 cross section in axial compression according to EUROCODE 3

In this paper theoretic basis of design of class 4 cross section in axial compression according to EN1993-1-5 is given. Design procedure is given as an flow chart and ilustrated with an worked example. Plate buckling is treated localy and globaly through the concept of effective cross sections. Interaction between plate-like and column-like behaviour of panels is carried out thought buckling reduction factors and final effective area of cross section

Analytical model of conductive graphite foam based sensors characteristics

Sensors play an important role in the control systems, because they provide the necessary information from surroundings to the controller of an automated systems. Today’s sensors are very sophisticated, with high accuracy, fast acquisition rate and good signal-to-noise ratio. But most of these sensors are too much expensive. Low cost sensor for measuring the force (pressure) or the displacement could be realized by utilizing conductive elastomer that exhibits property of changing the electrical resistance when the elastomer is deformed. This paper introduced a novel conductive graphite foam based sensors. The sensors are formed by inserting two thin copper wires within conductive foam, parallel to each other at the two opposite sides. The main problem of conductive foam based sensors is that the force-electrical resistance characteristic, or the displacement-electrical resistance characteristic, of conductive foam is highly nonlinear. This paper presents the analytical model of the conductive graphite foam sensors for measurement of the displacement. By measuring the changes in the electric resistance between two points of the foam and using the developed analytical model it should be possible to accurately estimate the displacement when the conductive foam is deformed