Optimization-based approach to the embodiment design of compliant mechanisms with different flexure hinges. - In: Advances in mechanism and machine science, (2019), S. 1579-1588
Fluid-mechanical compliant actuator for the insertion of a cochlear implant electrode carrier. - In: Mechanism and machine theory, Bd. 142 (2019), 103590, insges. 16 S.
In this paper an insertion method of electrode carriers of straight and curved form is shown for the use in cochlear implants. The aim of using a fluid-mechanical actuator is to minimise the contact between the electrode carrier and the cochlea and consequently avoiding damage during its insertion. First, the synthesis method used for beam-shaped fluid-mechanical actuators is shown. The model-based scaling of parameters demonstrates that actuators must be geometrically similar to reach the same form by same inner pressure. This fact facilitates the experimental investigations using up-scaled demonstrators. Electrode carriers as fluid-mechanical actuators of straight and curved form are designed by theory of curved rods for large deformations. For these carriers, a gentle insertion used a stylet and fluidic actuation in combination and is described analytically by the above mentioned theory. The results demonstrate that the insertion of a curved electrode carrier requires lower pressure and does not need any inner pressure in the end position. The measurements of the deformation behaviour of carrier demonstrators prove the validity of the analytical model. The maximum value of the differences between calculated and measured results of the inner pressure is about 10%.
https://doi.org/10.1016/j.mechmachtheory.2019.103590
Investigations of different compliant manipulator concepts for a high-precise rotational motion. - In: Proceedings of the 19th International Conference of the European Society for Precision Engineering and Nanotechnology, (2019), S. 64-67
Due to their advantages over conventional mechanisms, compliant mechanisms with notch flexure hinges are state of the art in precision engineering and micro systems technology. These compliant mechanisms are often used in positioning and adjustment applications with up to six degrees of freedom. In addition to the translational motions, as they are mainly required in linear tables and planar stages, also rotational motions are needed. For the realization of a high-precise rotation by compliant manipulators certain concepts with different complexity are existing. One approach is the use of flexure hinges with different geometrical parameters and notch shapes, which can be purposefully optimised depending on the requirements of the specific application. Another approach is the use of compliant mechanisms, in which the instantaneous centre of rotation represents the axis of rotation of the guided link either according to the remote centre of compliance concept or within the mechanism design space itself. In addition, a novel concept using a specific configuration of a four-bar mechanism, in which two adjacent links are of an equal length is presented in this contribution. The different approaches are compared by means of kinematic investigations and FEM-based simulations and the potential regarding a high-precise rotation with path deviations in the low micrometre range is shown.
Mechanical properties of an adjustable weighing cell. - In: Proceedings of the 19th International Conference of the European Society for Precision Engineering and Nanotechnology, (2019), S. 86-89
Optimization of compliant mechanisms by use of different polynomial flexure hinge contours. - In: Interdisciplinary applications of kinematics, (2019), S. 265-274
This paper presents the application of different polynomial flexure hinge contours in one compliant mechanism in order to increase both simultaneously the precision and the stroke of the output motion of compliant mechanisms. The contours of the flexure hinges are optimized in dependency of the required elasto-kinematic properties of the mechanism. This new approach for optimization is described in comparison to the use of identical common hinge contours. Based on previously optimized single polynomial flexure hinges, the validity of proposed guidelines is analyzed for a combination of several flexure hinges in two compliant mechanisms for linear point guidance. The rigid-body models of both mechanisms realize an approximated straight line as output motion. The compliant mechanisms are designed through the rigid-body replacement method and with different polynomial flexure hinges with orders varying from 2 to 16. The multi-criteria optimization is performed by use of non-linear FEM simulations. The derived values for the kinematic output parameters are compared for the ideal model and the optimized compliant mechanism. The results are discussed and conclusions for ongoing research work are drawn.
Compliant mechanisms for ultra-precise applications. - In: Interdisciplinary applications of kinematics, (2019), S. 249-256
This paper reports about enhanced compliant mechanisms with flexure hinge based on new analytic and/or FEM models that have been manufactured by state of the art wire EDM technology. Experimental proofs at test benches, equipped with ultra-precise interferometer based length and angular measurement systems, show first time the residual deviation to the intended path of motion with a resolution of nanometers/arc seconds. Theoretically determined and measured data are in good correlation. Repeatability limitations are rather more given by the residual noise of the overall test arrangement and mainly not by the mechanism itself.
Histological evaluation of a cochlear implant electrode array with the integration of an electrically activated shape memory alloy :
Histologische Evaluierung des Elektrodenträgers eines Cochlea-Implantats mit einer für elektrische Erwärmung integrierten Formgedächtnislegierung. - In: Laryngo-Rhino-Otologie, ISSN 1438-8685, Bd. 98 (2019), S 02, S299
https://doi.org/10.1055/s-0039-1686291
Development of a test bench for insertion force measurements with precise orientation of specimen using a stereo optical navigation system :
Entwicklung eines Versuchsstandes für die Insertionskraftmessung bei präziser Ausrichtung von Präparaten mittels stereooptischer Navigation. - In: Laryngo-Rhino-Otologie, ISSN 1438-8685, Bd. 98 (2019), S 02, S173-S174
https://doi.org/10.1055/s-0039-1686177
Coating stability and insertion forces of an alginate-cell-based drug delivery implant system for the inner ear. - In: Journal of the mechanical behavior of biomedical materials, ISSN 1878-0180, Bd. 97 (2019), S. 90-98
https://doi.org/10.1016/j.jmbbm.2019.05.007
Konzeption und Untersuchung eines bistabilen Sicherheitsventils und simulationsbasierte Entwicklung einer Methode zu dessen Dimensionierung. - Ilmenau : Universitätsverlag Ilmenau, 2019. - 1 Online-Ressource (XXI, 146 Seiten). - (Berichte der Ilmenauer Mechanismentechnik (BIMT) ; Band 5)
Technische Universität Ilmenau, Dissertation 2018
Sicherheitsventile für Gasrohrleitungen - sogenannte Gasströmungswächter - sind unverzichtbare mechanische Schutzvorrichtungen, die den unkontrollierten Austritt großer Gasmengen im Havariefall oder bei beabsichtigter Manipulation verhindern. Damit können Gasexplosionen und die resultierenden existenziellen Folgen abgewendet werden. Die bisher bekannten Lösungen für Sicherheitsventile weisen aufgrund ihres monostabilen Schaltverhaltens einen gravierenden Nachteil auf, da diese nach dem Auslösen selbsttätig wieder öffnen und somit den Gasstrom freigeben. Potentielle Gefahrenquellen bleiben damit unerkannt. Der wesentliche Vorteil eines neuartigen Sicherheitsventils besteht in der Realisierung einer bistabilen Schaltcharakteristik durch den Einsatz vorgespannter nachgiebiger Aufhängungselemente. Die zuverlässige Dimensionierung eines solchen neuartigen Ventils erweist sich in der Praxis als äußerst anspruchsvolle Aufgabe und erfordert viel Erfahrung, vor allem im Umgang mit numerischen Simulationswerkzeugen. Die vorliegende Arbeit beschäftigt sich intensiv mit der Untersuchung der nachgiebigen Aufhängungselemente und dem resultierenden Ventilschaltverhalten für unterschiedliche geometrische Abmessungen. Das Ziel und die Motivation der Arbeit besteht darin, die vorhandenen Hürden bei der Dimensionierung abzubauen und ein einfach anzuwendendes Dimensionierungsmodell zur Verfügung zu stellen. Die Ergebnisse der Arbeit stützen sich maßgeblich auf FEM-Simulationen zum Verformungsverhalten der nachgiebigen Aufhängungselemente. Anhand der ermittelten Kraft-Verschiebungs-Kennlinien ist es gelungen, das Schaltverhalten mathematisch anhand von abgeleiteten Dimensionierungsgleichungen zu beschreiben und darauf basierend eine Methode zur Dimensionierung neuartiger Sicherheitsventile zur Verfügung zu stellen. Darüber hinaus wurde das Dimensionierungsmodell anhand experimenteller Untersuchungen an realen Aufhängungselementen sorgfältig validiert. Zum Abschluss der Arbeit wurde auch das Verhalten von verschiedenen Ventilprototypen im praktischen Einsatz an Versuchsanlagen betrachtet. Die gewonnenen Erkenntnisse fließen in die Ergebnisse ein und gewährleisten eine hohe Qualität des Dimensionierungsmodells. Darüber hinaus können die Ergebnisse auch zur Dimensionierung von bistabilen Systemen in anderen Anwendungsfeldern genutzt werden.
https://nbn-resolving.org/urn:nbn:de:gbv:ilm1-2018000718