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Kinematics of the Lumbo-Pelvic Complex under Different Loading Conditions

Current Directions in Biomedical Engineering 2019年第1期5卷 347-349页

作者： Weidling, Martin Voigt, Christian Wendler, Toni Heilemann, Martin Werner, Michael Jarvers, Jan-Sven Heyde, Christoph-E. Center for Research on Musculoskeletal Systems (ZESBO) Faculty of Medicine University of Leipzig Semmelweisstrasse 14 Leipzig Germany Center for Research on Musculoskeletal Systems (ZESBO) Faculty of Medicine University of Leipzig Leipzig Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Dresden Germany Department of Orthopaedic Trauma and Plastic Surgery University Hospital Leipzig Leipzig Germany

The lumbo-pelvic complex is a highly complex structural system. The current investigation aims to identify the kinematics between interacting bone segments under different loading conditions. A specimen of the lumbo-pelvic complex was obtained from a human body donor and tested in a self-developed test rig. The experimental setup was designed to imitate extension, flexion, right and left lateral bending and axial rotation to the left and to the right, respectively. The vertebra L3 was firmly embedded and load was introduced via hip joints. Using a digital image correlation (DIC) system, the 3D motions of 15 markers at different landmarks were measured for each loadcase under cyclic loading. For each loadcase, the kinematics were analyzed in terms of three-dimensional relative movements between L3 and the sacrum. The usefulness of the experimental technique was demonstrated. It may serve for further biomechanical investigations of relative motion of sacroiliac and vertebral joints and deformation of bony structures. © 2019 by Walter de Gruyter Berlin/Boston.

关键词： Kinematics

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Burnishing of prismatic workpieces on three-axis machine enabled by closed loop force control

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Procedia CIRP 2019年 81卷 1028-1033页

作者： Marco Posdzich Chris Schöberlein Johannes Quellmalz Matthias Putz Chemnitz University of Technology Institute for Machine Tools and Production Processes (IWP) Reichenhainer Str. 70. 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology (IWU) Reichenhainer Str. 88. 09126 Chemnitz Germany

Burnishing is an effective chipless finishing process for improving workpiece properties: hardness, vibration resistance and surface quality. The product quality and process stability are significantly influenced by factors such as tool movement and burnishing force. The implementation of a force controlled tool positioning enables integration of finish operations like burnishing into conventional machining centers. This paper shows the realization of this new machine and process technology. The controller structure and tuning are discussed. In addition, the effects on the process forces and the workpiece are examined.

关键词： control micro forming finishing

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Non-cuttable material created through local resonance and strain rate effects (vol 10, 11539, 2020)

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SCIENTIFIC REPORTS 2020年第1期10卷 1-24页

作者： Szyniszewski, Stefan Vogel, Rene Bittner, Florian Jakubczyk, Ewa Anderson, Miranda Pelacci, Manuel Chinedu, Ajoku Endres, Hans-Josef Hipke, Thomas Durham University Durham United Kingdom Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Fraunhofer Institute for Wood Research Wilhelm-Klauditz-Institut WKI Hannover Germany Leibniz University Hannover Institute of Plastics and Circular Economy IKK Garbsen Germany University of Surrey Guildford United Kingdom University of Stirling Stirling United Kingdom

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

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Zero-error-production through inline-quality control of presshardened automotive parts by multi-camera systems

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IOP Conference Series: Materials Science and Engineering 2021年第1期1157卷

作者： A Pierer T Wiener L Gjakova J Koziorek Fraunhofer-Institute for Machine Tools and Forming Technology Chemnitz Germany VŠB - Technical University of Ostrava Faculty of Electrical Engineering and Computer Science Ostrava Czech Republic

Visual inspection often represents a bottleneck in the production chain due to limited receptivity and human fatigue. Depending on the inspection task, human classification error decisions greater than 10% are not uncommon. In order to make the manufacturing process more robust and sustainable, this paper presents innovative automated inline monitoring to realize a zero-error strategy in the field of industrial manufacturing. The central idea is to detect surface defects in the running production process by data fusion of a multi-camera system. Due to the required data analysis in conjunction with the targeted high throughput rates in production, this generates large amounts of data to process. Massively parallel hardware structures are used to enable defect detection within the production cycle. The paper especially addresses how to tackle boundary conditions in productive press-lines like the software-based mitigation of placement tolerances of parts and real-time capabilities. As a result, benefits could be achieved in terms of minimum detectable failure sizes and inspection speed, enabling 100% inline inspection of produced parts. The feasibility of the presented approach is demonstrated on realistic press-hardened deep-drawn automotive parts.

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Identification in the Frequency Domain of Mechanically Coupled Axes on Servo-Screw Presses

Identification in the Frequency Domain of Mechanically Coupl...

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International Conference on Control, Mechatronics and Automation (ICCMA)

作者： H. Kirchner J. Quellmalz H. Schlegel P. Müller Department of Control and Feedback Control Technology Technische Universität Chemnitz Germany Department of Forming Technology and Joining Fraunhofer Institut for Machine Tools and Forming Technology Dresden Germany

ISBN: (纸本)9781728137889

The article deals with the system identification of drive trains on forming machines. The aim is to analyze the mechanical properties in the frequency domain. A comparison of uncoupled single axes with several axes in a coupling system should provide information on whether different controller parameters or controller structures have to be adapted for both cases. This will be investigated using the example of an electromechanical die cushion on a servo screw press.

关键词： couplings dies (machine tools) fasteners forming processes presses servomechanisms press-in Servomechanism forming PROCESSES Fasteners Press Couplings axe Axis, Cervical Vertebra Frequency-domain analysis Axis Screw presses System identification coupling coupled system cushions

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Tool System for UV induced micro moulding of biomedical disposables 18

Tool System for UV induced micro moulding of biomedical disp...

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18th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2018

作者： Edelmann, J. Gärtner, E. Eckert, U. Griebel, J. Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Leibnitz IOM Leipzig Germany

ISBN: (纸本)9780995775121

A new approach for the generation of double-sided microstructured polymer films is presented based on injection-molding of urethane- and epoxy-based acrylates that are polymerized by irradiation with ultraviolet light (395 nm). Compared to hot embossing, this offers not only working under ambient conditions, but also a reduction of cycle time as well as flexibility regarding adjustment of the mechanical and/or chemical properties of the resulting polyacrylate film. A setup, consisting of the mold with the microstructured insert and two LED lamps emitting UV-light moved by a controllable stepper motor and a computer-based controller, was installed and successfully used for the fabrication of double-sided microstructured polyacrylate films. Therefore a new and innovative tool system for 2-component UV induced micro moulding of biomedical disposables was developed. The geometrical dimensions of the microstructures (e.g. fins, channels, sharp edges and slopes) require different technologies to machine the tool inserts. Therefore micromilling and μ-laserablation technologies were used in combination attached by laser polishing operations in special areas. A highly precise, complex designed tool system with mechanically moveable areas is needed to fill the tool with the 2 various chemical compositions. The paper presents the tool concept and explains the investigated surface treatment options. © 2018 CURRAN-CONFERENCE. All rights reserved.

关键词： Micromachining

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Parallel computing in automation of decoupled fluid-thermostructural simulation approach

arXiv

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arXiv 2019年

作者： Glänzel, Janine Naumann, Andreas Kumar, Tharun Suresh Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Dresden University of Technology Institute of Scientific Computing Dresden Germany

Decoupling approach presents a novel solution/alternative to the highly time-consuming fluidthermal-structural simulation procedures when thermal effects and resultant displacements on machine tools are analyzed. Using high dimensional Characteristic Diagrams (CDs) along with a Clustering Algorithm that immensely reduces the data needed for training, a limited number of CFD simulations can suffice in effectively decoupling fluid and thermal-structural simulations. This approach becomes highly significant when complex geometries or dynamic components are considered. However, there is still scope for improvement in the reduction of time needed to train CDs. Parallel computation can be effectively utilized in decoupling approach in simultaneous execution of (i) CFD simulations and data export, and (ii) Clustering technique involving Genetic Algorithm and Radial Basis Function interpolation, which clusters and optimizes the training data for CDs. Parallelization reduces the entire computation duration from several days to a few hours and thereby, improving the efficiency and ease-of-use of decoupling simulation approach. Copyright © 2019, The Authors. All rights reserved.

关键词： machine tools

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Effects of cooling lubricant on the thermal regime in the working space of machine tools

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Procedia Manufacturing 2019年 33卷 327-334页

作者： Michael Bräunig Joachim Regel Janine Glänzel Matthias Putz Institute for Machine Tools and Production Processes Technische Universität Chemnitz Reichenhainer Str. 70 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 09126 Chemnitz Germany

The use of cooling lubricant is indispensable for many milling and grinding machining tasks, primarily to achieve the best possible cooling and lubricating effect in the cutting zone and to reduce wear. In addition, tempered cooling lubricant carries out the function of heat removal from the working space. A reduction due to resource-efficient or ecological efforts has a direct impact on the temperature regime in the working space, which affects the thermal behavior of the frame structures and can cause machining inaccuracies. In this article, these effects of cooling lubricant on the thermal behavior of exemplary assemblies are modeled. Experimental investigations, based on temperatures and displacements, are compared with simulation-based calculations. The results include the description of the environmental conditions that must be taken into account when modeling frame structures and the influencing variables such as coolant temperature, supplied volume flow and extracted air volume.

关键词： machine tool thermal analysis cooling system CFD-simulation thermal modeling

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Kinematics of the Lumbo-Pelvic Complex under Different Loading Conditions

Kinematics of the Lumbo-Pelvic Complex under Different Loadi...

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作者： Weidling, Martin Voigt, Christian Wendler, Toni Heilemann, Martin Werner, Michael Jarvers, Jan-Sven Heyde, Christoph-E. Faculty of Medicine University of Leipzig Semmelweisstrasse 14 Leipzig Germany Faculty of Medicine University of Leipzig Leipzig Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Dresden Germany Department of Orthopaedic Trauma and Plastic Surgery University Hospital Leipzig Leipzig Germany

关键词： Kinematics

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Effect of sample geometry on the macroscopic shear deformation of the titanium alloy Ti-10V-2Fe-3Al subjected to quasi-static and dynamic compression-shear loading

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IOP Conference Series: Materials Science and Engineering 2021年第1期1147卷

作者： S Winter M Scholze M F-X Wagner Institute of Materials Science and Engineering Materials Science Group Chemnitz University of Technology 09125 Chemnitz Germany now at Fraunhofer Institute for Machine Tools and Forming Technology IWU 09126 Chemnitz Germany

We investigate the evolution of shear bands in a Ti-10V-3Fe-2Al alloy with three different initial microstructures: solution-annealed β-titanium, β-titanium with primary α-phase precipitates as well as a condition with primary and secondary α-phase precipitates. Quasi-static and dynamic testing of compression-shear specimens with strain rates of 10-3 s-1 and 102 s-1 is performed at room temperature. The influence of two different sample geometries on the macroscopic shearing tendency is investigated: samples with a cylindrical cross section and samples with a square cross section. The results of digital image correlation and the nominal stress-strain behavior under quasi-static and dynamic loading indicate a stronger localization tendency of the aged conditions with additional α-phase precipitates compared to the solution-annealed pure β-condition. Our results also demonstrate that compression-shear testing with samples with a square cross-section reduces facet loss, increases the resolution even at high strain rates and therefore allows to analyze strain distributions during shear band formation and propagation with higher accuracy.

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