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Simulation Method for the Floating of Hydrodynamic Guides

Procedia CIRP 2017年 62卷 346-350页

作者： Martin Gläser Volker Wittstock Andreas Hirsch 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 Straße 88 09126 Chemnitz Germany

The flowing lubricant in the oil wedge between the slide and guide rail creates hydrodynamic pressure that leads to a displacement of the carriage, which depends on the sliding surface geometry and the slides velocity. This paper describes an approach to calculate the resulting complex displacement. Therefore, two methods were combined. The simulation of the floating by using the finite difference method was integrated in the numerical calculation of the balance of the whole carriage. Considering a real sliding surface geometry of a test bench, the experiment verification of the approach for velocities up to 40m/min showed a good conformity.

关键词： oil wedge hydrodynamic guides simulation

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Heat Sources and Fluxes in Milling: Comparison of Numerical, Analytical and Experimental Results

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Procedia CIRP 2017年 58卷 97-103页

作者： Matthias Putz Christian Oppermann Michael Bräunig Umut Karagüzel Fraunhofer-Institute for Machine Tools and Forming Technology IWU 09126 Chemnitz Germany Chemnitz University of Technology 09010 Chemnitz Germany Mechanical Engineering Department Istanbul Technical University 34437 Istanbul Turkey

The paper describes the comparison of numerical solution, analytical approach and experimental results calculating heat sources and heat fluxes in a milling process with the aim of the calculation of the temperature distribution. Analytical solutions for standard geometries are superposed in order to represent the tool best possible. Exposed with the heat sources calculated by finite element simulation of the interrupted chip formation process the solution of these analytical representation is compared with numerical ones. These have been investigated in previous research on a consistent numerical simulation method for calculation of heat sources and fluxes in milling. Both models are fitted and verified by cutting experiments.

关键词： Finite element Method Simulation Analytical solution Experimentation

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Consistent Simulation Strategy for Heat Sources and Fluxes in Milling

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Procedia CIRP 2017年 62卷 239-244页

作者： Matthias Putz Christian Oppermann Ulrich Semmler Michael Bräunig Umut Karagüzel Fraunhofer Institute for Machine Tools and Forming Technology IWU 09126 Chemnitz Germany Chemnitz University of Technology 09010 Chemnitz Germany Mechanical Engineering Department Istanbul Technical University 34437 Istanbul Turkey

The paper presents a consistent numerical simulation method for calculation of heat sources and heat fluxes in milling processes. First of all, by means of finite element simulation of the interrupted chip formation process the cutting heat source is calculated. Next, the non-steady-state heat fluxes into the workpiece, the chips and the tool are computed numerically. The computed fluxes serve as boundary conditions for thermo-mechanical FE workpiece and tool models. The numerical models are fitted and verified by experiments of S235 steel. The simulations show a good match with the force and temperature measurements of the cutting processes.

关键词： Milling Finite element method Simulation Experimentation

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Train Front Module in Aluminium-foam-sandwich Design

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Lightweight Design worldwide 2017年第6期10卷 12-17页

作者： Susi Rybandt Carsten Lies Thomas Hipke Institut für Werkzeugmaschinen und Produktionsprozesse at TU Chemnitz Chemnitz Germany Functional Integration/Lightweight Design at the Fraunhofer Institute for Machine Tools and Forming Technology (IWU) Chemnitz Germany

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Inherent process monitoring for piezoceramic transducer integration 16

Inherent process monitoring for piezoceramic transducer inte...

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16th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2016

作者： Drossel, W.-G. Schubert, A. Putz, M. Koriath, H.-J. Wittstock, V. Peter, S. Hensel, S. Nestler, M. Jahn, S.F. Müller, R. Pierer, A. Müller, B. Schmidt, M. Fraunhofer Institute for Machine Tools and Forming Technology Germany TU Chemnitz Germany

ISBN: (纸本)9780956679086

A new technology enables the integration of piezoceramic fibres as functional elements into micro-structured aluminium sheets by forming processes. Scope of the paper is the development of a novel method for monitoring the condition of piezoceramic fibres during the joining by forming process. For this purpose, the piezoceramic fibres are utilized as material inherent sensor during forming tests. Test samples are fabricated and electrically characterized by impedance spectroscopy. Furthermore, numerical results of the stress state of the piezoceramic/metal composites are presented. Depending on the results a novel process-control is outlined that aims on preload-monitoring of the piezoceramics with the surrounding metal structure.

关键词： Process monitoring

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Comparative Integrated Manufacturing Efficiency in Production Engineering

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Procedia CIRP 2017年 63卷 527-532页

作者： A.P. Kuznetsov H.-J. Koriath A.V. Kalyashina Moscow State University of Technology “STANKIN” 127055 Moscow Russia Fraunhofer Institute for Machine Tools and Forming Technology IWU 09126 Chemnitz Germany Kazan National Research Technical University Kazan Russia

At present a plurality of manufacturing methods, different manufacturing processes and manufacturing equipment are known in order to produce and customize work pieces and products. A new systematic approaches for the analysis and evaluation of manufacturing methods bases on the energy-information model as a conceptual approach to the comparative integrated manufacturing efficiency in production engineering. The integrated manufacturing efficiency is equal to the product of the efficiencies of matter, energy and information. The Comparative Integral Manufacturing Efficiency is the product of Quality rate, Effectiveness, Availability, devided by the product of (used Energy, used material, Emission ratio). A case study compares additive and removal process efficiencies for the production of a hollow cylinder. Proposed method for comparative integrated manufacturing efficiency will offer resource-efficient strategies for the creation and optimization of processes and technology applications.

关键词： manufacturing efficiency technological process

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Multiscale Multiphysics Simulation of a Pulsed Electrochemical Machining Process with Oscillating Cathode for Microstructuring of Impact Extrusion Punches

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Procedia CIRP 2017年 58卷 257-262页

作者： Ingo Schaarschmidt Mike Zinecker Matthias Hackert-Oschätzchen Gunnar Meichsner Andreas Schubert Professorship Micromanufacturing Technology Faculty of Mechanical Engineering Chemnitz University of Technology D-09107 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Strasse 88 D-09126 Chemnitz Germany

The pulsed electrochemical machining (PECM) with oscillating cathode is a manufacturing technology which is used for shaping and surface structuring of different workpieces, e.g. impact extrusion punches. The principle behind the ECM-process is the controlled anodic dissolution of the workpiece material without any thermal or mechanical impact and independent from workpiece material hardness. In this study, a new multi-scale approach for the modelling of PECM with oscillating cathode was created integrating the short and long time scale physical phenomena. In the short time scale simulation step (t < 0.02 s) the physical processes (current density distribution, motion of cathode, heat and hydrogen generation) during one single oscillation were analyzed. An averaged dissolution speed at the anode boundary over the small time range was calculated. The averaged values were imported as initial and boundary conditions into the long times scale simulation step (t > 10 s). Within this simulation step, the anodic dissolution was simulated by deforming the geometry. This approach allows simulations for long overall time ranges (t > 1000 s) while considering the short times scale processes in combination with a relatively small computational effort. This multiscale and multiphysics model helps to analyze the differences between front and lateral working gap and supports the process design for the pulsed electrochemical machining with oscillating cathode.

关键词： Electro chemical machining (ECM) Material removal Multiscale-multiphysics-modelling

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Characterization of an Electrochemical Machining Process for Precise Internal Geometries by Multiphysics Simulation

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Procedia CIRP 2017年 58卷 175-180页

作者： Matthias Hackert-Oschätzchen Raphael Paul Michael Kowalick Danny Kuhn Gunnar Meichsner Mike Zinecker Andreas Schubert Professorship Micromanufacturing Technology Faculty of Mechanical Engineering Chemnitz University of Technology D-09107 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Strasse 88 D-09126 Chemnitz Germany

In several fields of mechanical engineering internal precision geometries are applied. For this, application requirements like high shape accuracy, sufficient stability, high wear resistance or an increase of life time have to be fulfilled. However, there is also a demand on quick and precise manufacturing processes that are flexible in machining various internal geometries. Electrochemical machining (ECM) is a process which meets these requirements. This process allows surface structuring and shaping of metal components with high shape accuracy independently of the materials strength and hardness [1] . This study presents investigations on a developed process design for manufacturing internal precision geometries by pulsed electrochemical machining (PECM) with help of multiphysics simulations. The peculiarity of this process is the shaping of the workpiece by the lateral working gap. Multiphysics simulations were carried out to understand the respective interactions between several physical phenomena. Especially, fluid dynamical effects are described in detail within the developed model. Furthermore, Joule heating and cathodic hydrogen formation are included. The fluid flow ensures the removal of heat and hydrogen and a continual supply with fresh electrolyte, respectively. The electrical conductivity of the electrolyte is modeled as a function of hydrogen volume concentration and temperature. Hence, both effects, Joule heating and hydrogen formation, influence the current density distribution which in turn determines the material removal.

关键词： Electrochemical machining (ECM) Finite element method (FEM) Multiphysics Simulation

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Testing of magnetic pulse welded joints – Destructive and non-destructive methods

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AIP Conference Proceedings 2019年第1期2113卷

作者： Verena Psyk Christian Hofer Koen Faes Christian Scheffler Edgar Scherleitner 1Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Strasse 88 09126 Chemnitz Germany 2Research Center for Non Destructive Testing GmbH (RECENDT) Altenberger Straße 69 4040 Linz Austria 3Belgian Welding Institute BWI Technologiepark 935 9052 Zwijnaarde Belgium

Electromagnetic pulse welding is an innovative technology suitable for joining various similar and dissimilar tube and sheet metal parts including dissimilar material combinations, which are difficult to join by conventional, i.e. thermal welding methods. In case of proper choice of process parameters, a high joint quality can be achieved. In literature this is often demonstrated by failure in the base material during destructive testing. However, no standard testing procedures for magnetic pulse welded joints have been agreed on and thus industrial implementation is severely complicated. Specifically, investigations regarding non-destructive testing are rarely available. The paper evaluates different testing and characterization methods. Specifically, metallographic analysis and lap shear tests are taken into consideration. Finally, Laser UltraSound (LUS) is presented as a new alternative for characterizing magnetic pulse welded joints. The technique is based on measuring laser ultrasound waves which are either transmitted through or reflected by the weld seam. A comparison of the results to those of the more established destructive testing methods shows, that LUS measurements absolutely allow qualitative and quantitative conclusions regarding weld quality. Due to high automation potential, the method is a promising alternative for quality control in industrial manufacturing.

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Sensing and Actuating Functions by Shape Memory Alloy Wires Integrated into Fiber Reinforced Plastics

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Procedia CIRP 2017年 66卷 249-253页

作者： Björn Senf Thomas Mäder Iñaki Navarro y de Sosa André Bucht Marcus Knobloch David Löpitz Welf-Guntram Drossel Fraunhofer Institute for Machine Tools and Forming Technology IWU Noethnitzer Strasse 44 01187 Dresden Germany Technische Universität Chemnitz Reichenhainer Straße 70 09126 Chemnitz Germany

Lightweight design based on fiber reinforced plastics (FRP) has potential for improvement by integration of sensors and actuators made of smart material filaments. Regarding FRP with integrated actuating shape memory alloy (SMA) wires, this paper presents important characteristics of such an adaptive composite and its components for design purposes. Beyond that, the first successful pultrusion processing of sensing SMA wires is proposed to address lightweight design mass production for safety-related applications. Measurements of this smart composite structure with strain sensor functionality proved high sensitivity compared to conventional sensors.

关键词： shape memory alloy wires SMA fiber refinorced plastics FRP lightweight design smart composite structure pultrusion

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