Scientific publications without theses

Results: 319
Created on: Sun, 26 Mar 2023 15:12:38 +0200 in 0.0828 sec

Linß, Sebastian; Henning, Stefan; Zentner, Lena
Modeling and design of flexure hinge-based compliant mechanisms. - In: Kinematics, (2019), S. 1-24

A compliant mechanism gains its mobility fully or partially from the compliance of its elastically deformable parts rather than from conventional joints. Due to many advantages, in particular the smooth and repeatable motion, monolithic mechanisms with notch flexure hinges are state of the art in numerous precision engineering applications with required positioning accuracies in the low micrometer range. However, the deformation and especially motion behavior are complex and depend on the notch geometry. This complicates both the accurate modeling and purposeful design. Therefore, the chapter provides a survey of different methods for the general and simplified modeling of the elasto-kinematic properties of flexure hinges and compliant mechanisms for four hinge contours. Based on non-linear analytical calculations and FEM simulations, several guidelines like design graphs, design equations, design tools or a geometric scaling approach are presented. The obtained results are analytically and simulatively verified and show a good correlation. Using the example of a path-generating mechanism, it will be demonstrated that the suggested angle-based method for synthesizing a compliant mechanism with individually shaped hinges can be used to design high-precise and large-stroke compliant mechanisms. The approaches can be used for the accelerated synthesis of planar and spatial flexure hinge-based compliant mechanisms.
Sumi, Susanne; Böhm, Valter; Schorr, Philipp; Zentner, Lena; Zimmermann, Klaus
Compliant class 1 tensegrity structures for gripper applications. - In: EuCoMeS 2018, (2019), S. 392-399

This paper describes concepts for finger-grippers based on compliant multistable class 1 tensegrity structures. Two of these concepts are selected and examined in detail. With theoretical investigations the member parameters and the resulting gripping forces are determined. There are done dynamical analyses of one of these grippers to obtain the behaviour with an actuation force. Moreover demonstrators of both grippers are built.
Zentner, Lena; Linß, Sebastian
Compliant systems : mechanics of elastically deformable mechanisms, actuators and sensors. - Berlin : De Gruyter, 2019. - IX, 166 Seiten ISBN 3-11-047731-9
Literaturverzeichnis: Seite 157-164

Darnieder, Maximilian; Torres, Mario; Linß, Sebastian; Theska, René; Zentner, Lena; Fröhlich, Thomas
Modellierung der Drehsteifigkeit dünner Festkörpergelenke in der Präzisionsgerätetechnik. - In: Jahrbuch Optik und Feinmechanik, ISSN 0075-272X, Bd. 64 (2018), S. 139-165

Festkörpergelenke werden seit langem in verschiedensten Bereichen der Feinwerktechnik eingesetzt, besonders dort, wo erhöhte Anforderungen an die Präzision bestehen. Beispiele dafür sind Präzisionswaagen und Massekomparatoren, die bereits eine beeindruckende Leistungsfähigkeit erreicht haben. Dies ist nicht zuletzt auf die genaue Kenntnis der mechanischen Eigenschaften und deren Modellierung zurückzuführen. Dennoch ergeben viele in der Literatur verfügbare analytische Modellgleichungen zur Berechnung der Drehsteifigkeit der hier typischen, besonders dünnen Festkörpergelenke eine Abweichung von rund 10 % gegenüber dem 3D-Modell basierend auf der Finiten-Elemente-Methode. Dies wird anhand der genauen Betrachtung des Spannungszustandes im belasteten Gelenk aufgezeigt und ist ein relevanter Aspekt für die Entwicklung von Geräten für Präzisionsanwendungen und deren Justierung. Der Beitrag beleuchtet dieses Phänomen im Detail, zeigt Grenzen verschiedener Modellansätze in Abhängigkeit der Geometrie auf und bietet dem Leser einen Vorschlag zur präzisen Modellierung in einem großen Parameterraum an, die ohne eine aufwändige Finite-Elemente-Analyse auskommt.

Torres Melgarejo, Mario André; Darnieder, Maximilian; Linß, Sebastian; Zentner, Lena; Fröhlich, Thomas; Theska, René
On modeling the bending stiffness of thin semi-circular flexure hinges for precision applications. - In: Actuators, ISSN 2076-0825, Bd. 7 (2018), 4, 86, S. 1-16

Compliant mechanisms based on flexure hinges are widely used in precision engineering applications. Among those are devices such as precision balances and mass comparators with achievable resolutions and uncertainties in the nano-newton range. The exact knowledge of the mechanical properties of notch hinges and their modeling is essential for the design and the goal-oriented adjustment of these devices. It is shown in this article that many analytical equations available in the literature for calculating the bending stiffness of thin semi-circular flexure hinges cause deviations of up to 12% compared to simulation results based on the three-dimensional finite element model for the considered parameter range. A close examination of the stress state within the loaded hinge reveals possible reasons for this deviation. The article explains this phenomenon in detail and shows the limitations of existing analytical models depending on specific geometric ratios. An accurate determination of the bending stiffness of semi-circular flexure hinges in a wide range of geometric parameters without the need for an elaborate finite element analysis is proposed in form of FEM-based correction factors for analytical equations referring to Euler-Bernoulli's beam theory.
Rau, Thomas S.; Suzaly, Nuha; Pawsey, Nick; Hügl, Silke; Lenarz, Thomas; Majdani, Omid
Histological evaluation of a cochlear implant electrode array with electrically activated shape change for perimodiolar positioning. - In: Biomedical engineering, ISSN 1862-278X, Bd. 63 (2018), S1, Seite S135
Enthalten in: Biomedical Implants and Devices (2)
Hügl, Silke; Blum, Tobias; Lenarz, Thomas; Majdani, Omid; Rau, Thomas S.
Impact of anatomical variations on insertion forces - an investigation using artificial cochlear models. - In: Biomedical engineering, ISSN 1862-278X, Bd. 63 (2018), S1, Seite S330
Enthalten in: Poster Session
Rau, Thomas S.; Witte, Sina; Uhlenbusch, Lea; Lexow, G. Jakob; Hügl, Silke; Kahrs, Lüder A.; Majdani, Omid; Lenarz, Thomas
Minimally invasive mastoidectomy approach using a mouldable surgical targeting system : a proof of concept. - In: Biomedical engineering, ISSN 1862-278X, Bd. 63 (2018), S1, Seite S247
Enthalten in: Computer Assisted Surgery
Henning, Stefan; Linß, Sebastian; Zentner, Lena
detasFLEX - a computational design tool for the analysis of various notch flexure hinges based on non-linear modeling. - In: Mechanical sciences, ISSN 2191-916X, Bd. 9 (2018), 2, S. 389-404

A novel computational design tool to calculate the elasto-kinematic flexure hinge properties is presented. Four hinge contours are implemented. It is shown, that FEM results correlate well with the analytical design tool results. For a given deflection angle of 10˚ and a corner-filleted contour, the deviations of the bending stiffness are between 0.1 % and 9.4 %. The design tool can be beneficial for the accelerated and systematic synthesis of compliant mechanisms with optimized flexure hinges.
Hügl, Silke; Rülander, Katharina; Lenarz, Thomas; Majdani, Omid; Rau, Thomas S.
Investigation of ultra-low insertion speeds in an inelastic artificial cochlear model using custom-made cochlear implant electrodes. - In: European archives of oto-rhino-laryngology and head & neck, ISSN 1434-4726, Bd. 275 (2018), 12, S. 2947-2956