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International Symposium on Material Science and Engineering, ISMSE 2017

作者： Hackert, Alexander Drebenstedt, Claudia Timmel, Tristan Osiecki, Tomasz Kroll, Lothar Technische Universität Chemnitz Department of Lightweight Structures and Polymer Technology Institute of Lightweight Structures Faculty of Mechanical Engineering Chemnitz09107 Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Mechatronics and Lightweight Structures Reichenhainer Straße 88 Chemnitz09126 Germany

ISBN: (纸本)9783035711165

The combination of metals and fiber reinforced plastics is also known as hybrid metal composites. They offer the fusion of the good static mechanical properties of the fiber reinforced plastics and the good dynamic mechanical properties of the metal. For that reason, parts made of hybrid metal composites are predestined for the use as load relevant parts. The purpose of this study was to develop new technologies for semi finished hybrid metal composite materials. Thermoplastic Fiber-Reinforced Composites (TP-FRC) were arranged with new, isotropic, closed pore Aluminum Foam (AF) structures to an Extrinsically Combined Composite Sandwich (ECCS) by adhesive bonding. They form the basis for novel weight-optimized as well as cost-effective applications. The entire manufacturing process for the continuous semi-finished product was examined and verified according DIN EN 2563. This was done with regard to subsequent characterization by the specific bending modulus and specific bending stiffness. The examinations show a high bending stiffness and high strength structures combined with excellent damping properties at high damage tolerances. These are the most requested in automotive applications. © 2017 Trans Tech Publications, Switzerland.

关键词： Carbon fiber reinforced plastics

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Evaluation of Measures for Thermo-sensitive Design and Operating of machine Tool Structures

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Procedia CIRP 2017年 60卷 14-19页

作者： Joachim Regel Volker Wittstock 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 variance-based sensitivity analysis can be used as a statistical procedure to evaluate different individual measures to influence the thermal behaviour of machine tools. It provides specific ratios for parameters affecting the variance of the output parameters that are not comparable in any other way. This method is implemented by means of large samples used in a simulation model which reduces computing time and is oriented towards physical objects. Furthermore, conditional and total variances are estimated. The article describes the principles of modelling with discrete elements to integrate all variants into one simulation model, the definition of input and output parameters and sample generation considering the parameter-specific distribution functions and parameter dependences. To evaluate the applied measures, temperatures, temperature differences, heat flow and time required until achieving thermal equilibrium are examined as such, or in relation to the deployed energy. The implementation is demonstrated by means of two examples. One refers to the design, and the other one deals with the operation phase of existing machine tools.

关键词： machine tool sensitivity analysis thermal measures design phase adaptive cooling

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Embedding electronics into additive manufactured components using laser metal deposition and selective laser melting

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Procedia CIRP 2018年 74卷 168-171页

作者： Torsten Petrat Robert Kersting Benjamin Graf Michael Rethmeier Fraunhofer Institut for Production Systems and Design Technology Pascalstraße 8-9 10587 Berlin Germany Federal Institute for Materials Research and Testing Unter den Eichen 87 12205 Berlin Germany Technical University Berlin Institute of Machine Tools and Factory Management Pascalstraße 8-9 10587 Berlin Germany

The paper deals with the integration of a light emitting diode (LED) into an additive manufactured metal component. Selective laser melting (SLM) and laser metal deposition (LMD) are used. The material used is the chrome-nickel steel 316L. The basic component is manufactured by means of SLM and consists of a solid body and an area with grid structure. The solid body includes a duct in the shape of a groove with a recess for the positioning of the power cable. The LED is embedded in the grid structure via an inlet from the solid body. In further processing, the groove is filled with LMD. Two strategies with different parameter combinations were investigated. It shows that a high energy input near the power cable leads to its destruction. By using multiple parameter combinations during the manufacturing process, this destruction can be prevented. There was a comparison of both strategies with regard to the necessary number of tracks and duration of welding time.

关键词： additive manufacturing condition monitoring process chain laser-metal-deposition selektive-laser-melting embedded electronics

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Laser-plasma-cladding as a hybrid metal deposition-technology applying a SLM-produced copper plasma nozzle

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Procedia CIRP 2018年 74卷 738-742页

作者： Christian Brunner-Schwer Robert Kersting Benjamin Graf Michael Rethmeier Fraunhofer Institut for Production Systems and Design Technology Pascalstraße 8-9 10587 Berlin Germany Federal Institute for Materials Research and Testing Unter den Eichen 87 12205 Berlin Germany Technical University Berlin Institute of Machine Tools and Factory Management Pascalstraße 8-9 10587 Berlin Germany

Laser-Metal-Deposition (LMD) and Plasma-Transferred-Arc (PTA) are well known technologies which can be used for cladding purposes. The prime objective in combining LMD and PTA as a Hybrid Metal Deposition-technology (HMD) is to achieve high deposition rates at low thermal impact. Possible applications are coatings for wear protection or repair welding for components made of steel. The two energy sources (laser and plasma arc) build a joint process zone and are configurated to constitute a stable process at laser powers between 0.4-1 kW (defocused) and plasma currents between 75-200 A. Stainless steel 316L serves as filler material. For this HMD process, a plasma Cu-nozzle is designed and produced by powder bed based Selective Laser Melting. The potential of the HMD technology is investigated and discussed considering existing processes. This paper demonstrates how the interaction of the two energy sources effects the following application-relevant properties: deposition rate, powder efficiency and energy input.

关键词： Laser-Metal-Deposition Plasma-Transferred-Arc SLM printed plasma torch Laser-Plasma-Hybrid

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Numerical simulation of thermal supported self-pierce riveting of an ultra high-strength aluminium alloy

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Journal of Physics: Conference Series 2018年第1期1063卷

作者： M Jäckel S Maul C Kraus W-G Drossel Fraunhofer Institute for Machine Tools and Forming Technology IWU Nöthnitzer Str. 44 01187 Dresden Germany

This paper will describe the experimental and numerical analysis of the thermal supported self-pierce riveting process of EN AW-6016 T4 into EN AW-7075 T6. In this regard, the experimental process analysis, the develo...

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Acoustical optimization of a train gearbox based on overall system simulation 45

Acoustical optimization of a train gearbox based on overall ...

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45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future, INTER-NOISE 2016

作者： Troge, Jan Drossel, Welf-Guntram Hensel, Eric Zumach, Sebastian Bräunig, Jan Fraunhofer Institute for Machine Tools and Forming Technology IWU Dresden Germany

The present article deals with the simulative representation and optimization of acoustical properties of a train gearbox with one helical gear stage. At first, a dynamic model of the initial gearbox based on manufacturer construction parameters was built up. Based on this model, the gear mesh excitation as a main source of structure-borne sound has been calculated. Within the simulation model relevant influences on gear mesh excitation e.g. housing and shaft deformations or bearing stiffnesses have been considered by including flexible structures. By reference to these simulation results, the first optimization step was to change gear micro geometry to reduce system excitation. Based on analysis of system dynamics, as well as the calculation of averaged surface velocities, critical rotational speeds have been identified for a given input torque. For these critical rotational speeds, interface parameters, which are necessary for the following numerical sound radiation simulation, have been determined. On the basis of the simulated mode shapes and operational deflection shapes, a structural optimization of the gearbox housing was performed by considering installation space and mass specifications. The acoustical characterization of different optimization variants has been realized by comparing the emitted sound power levels determined by numerical simulation. © 2016, German Acoustical Society (DEGA). All rights reserved.

关键词： Flexible structures

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Highly elastic strain gauges based on shape memory alloys for monitoring of fibre reinforced plastics 21st

Highly elastic strain gauges based on shape memory alloys fo...

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21st Symposium on Composites, 2017

作者： Mäder, Thomas De Sosa, Iñaki Navarro Y. Senf, Björn Wolf, Peter Hamm, Martin Zoch, Martin Drossel, Welf-Guntram Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 Chemnitz09126 Germany Prof. for Adaptronics and Lightweight Design Technische Universität Chemnitz Chemnitz09107 Germany FiberCheck GmbH Technologie-Campus 1 Chemnitz09126 Germany

ISBN: (纸本)9783035711981

Conventional strain gauges made of constantan or CuCr for instance have a low value for structural health monitoring issues in plastic composites. These strain sensor materials exhibit small elastic regions and show fatigue when dynamically loaded with strain levels over 0.3 percent. For this reason, these sensors would break or fail before the composite life-time and thus cannot be integrated into this kind of composite materials. Pseudoelastic thermal shape memory alloys are therefore used as strain sensors and integrated into composites in order to allow piezoresistive strain measurement and structural health monitoring in such materials. Thermal treatments are used to create sensor structures out of shape memory alloy wires. Pseudoelastic shape memory wires can be strained up to 8 percent repeatedly. Their gauge factor is higher than 5. Shape memory strain sensors are successfully embedded into glass fibre reinforced plastics and show a significant and reproducible resistance change when the composite is strained. The dynamic strength is magnificently higher compared to conventional strain gauges. Shape memory strain sensors are an efficient alternative to fiber-bragg-grating sensors and can potentially be used for strain measurements in different plastics and textile materials. Shape memory sensor structures can be embedded or applied and are good candidates for structural characterisation and monitoring applications. © 2017 Trans Tech Publications, Switzerland.

关键词： Strain gages

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Simulation Method for the Floating of Hydrodynamic Guides

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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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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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