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56th International Conference on Vibroengineering

作者： Windisch, Thomas Hensel, Eric Drossel, Welf-Guntram Fraunhofer-Institute for Machine Tools and Forming Technology IWU Chemnitz Germany

Planetary gears in wind power plants transmit force excitations to the mechanical structure due to alternating tooth meshes. Structure-borne sound is generated and proceeds to tower and nacelle where it is radiated to the environment and may be a noise pollution to residents. In addition, unwanted vibrations can decrease the durability of the gearbox. So far, structural vibrations are being avoided by constructive measures or active absorbers. In contrast to this, our approach is to reduce gear mesh excitations only with the existing electric generator. Therefore, the rotor current control of the machine is enhanced to inject high frequency oscillations so that the wind power generator produces a specific oscillating torque. This anti-noise torque ripple is transmitted via the shaft to the gear stage and minimizes the gear mesh orders so that less force excitations are exposed to the mechanical structure at the bearings. In our knowledge this anti-noise torque approach using the electric generator and its current control is completely new in the field of wind power plants. Simulation is performed using a multi-body-model of the drivetrain to identify an optimal torque oscillation. Afterwards a control circuit model of the generator and the power converter for the rotor circuit is shown. Hence, it is possible to calculate the behavior of the system in high level of detail on the mechanical and the electrical side. Resulting bearing forces are analyzed to prove that excitation can be reduced significantly. No additional hardware, especially no additional actor is needed. Copyright © 2022 Thomas Windisch, et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

关键词： Acoustic noise

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Intelligent parameter determination and quality control of an injection molding process 17

Intelligent parameter determination and quality control of a...

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17th CIRP Conference on Intelligent Computation in Manufacturing Engineering, CIRP ICME 2023

作者： Nahvi, Sina Schumann, Marco Dix, Martin Klimant, Philipp Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 Chemnitz09126 Germany Institute for Machine Tools and Production Processes Chemnitz University of Technology Reichenhainer Str. 70 Chemnitz09126 Germany

One of the most extensively utilized techniques for material processing is injection molding, which is used to manufacture highly accurate and complex plastic items. In order to produce qualified items and ensure quality of the products, process parameter determination is crucial. We propose and compare two approaches for intelligently determining the parameters and controlling the quality within the injection molding process while aiming towards zero defects. These approaches are combinations of the process model trained using Automated machine Learning (AutoML) with optimization techniques based on Bayesian and genetic algorithms. © 2024 Elsevier B.V.. All rights reserved.

关键词： Injection molding

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Pattern matching for mathematical expressions with OpenMath 14

Pattern matching for mathematical expressions with OpenMath

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Joint of the 5th Workshop on Formal Mathematics for Mathematicians, FMM 2019, 2nd Workshop on Formal Verification of Physical Systems, FVPS 2021, 13th Workshop on Mathematical User Interaction, MathUI 2021, 2021 Workshop on Natural Formal Mathematics, NatFoM 2021, and 31st OpenMath Workshops, OM 2021 Doctoral Program and Work in Progress at the 14th Conference on Intelligent Computer Mathematics, CICM-WS 2021

作者： Wenzel, Ken Fraunhofer-Institute for Machine Tools and Forming Technology IWU Chemnitz Germany

An OpenMath Content Dictionary with symbols for pattern matching of tree-like structures is presented. Furthermore, a mapping to RDF and SPARQL is introduced that allows to execute search queries against an OpenMath R... 详细信息

关键词： Pattern matching

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Simulation concept for surface designs increasing the coefficient of static friction 22

Simulation concept for surface designs increasing the coeffi...

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22nd International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2022

作者： Walther, Franz Wieland, Sebastian Schneider, Jörg Edelmann, Jan Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany

ISBN: (纸本)9781998999118

The objective of the simulation concept for the design of surfaces is the prediction of trends relating to the coefficient of static fric-tion of two friction partners. For the overall consideration, further influencing variables have to be considered, since an exclusive focus on the coefficient of static friction can only inadequately describe the complex tribological behaviour when two surfaces come into contact. To calculate these characteristic values, a multi-stage simulation and calculation approach was developed in which, starting from the generation of experimentally measured or artificially generated surface topography data (stage 1), the true contact area as well as the stress and deformation behaviour when two surfaces come into contact are simulated in contact simula-tions (stage 2). Finally, the coefficient of static friction is calculated based on a micro-roughness model taken from the literature and statistical homogenization (stage 3). The accuracy and validity of the workflow was demonstrated in the experimental valida-tion using ground sample surfaces. Trends with regard to the coefficients of static friction were reliably represented. In addition a method for generating synthetic stochastic surfaces as simulation input was developed. Due to the given comparability with experi-mental surfaces in terms of the geometric properties and the resulting friction behaviour, virtual surfaces can also be used in the future as input of the multistage calculation workflow and applied in simulative parameter studies. © European Society for Precision Engineering and Nanotechnology, Conference Proceedings - 22nd International Conference and Exhibition, EUSPEN 2022. All rights reserved.

关键词： Surface roughness

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OpenMath-RDF: RDF encodings for OpenMath objects and Content Dictionaries 14

OpenMath-RDF: RDF encodings for OpenMath objects and Content...

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作者： Wenzel, Ken Fraunhofer-Institute for Machine Tools and Forming Technology IWU Chemnitz Germany

This paper presents RDF encodings for OpenMath objects and Content Dictionaries that allow mathematical objects and symbol definitions to be first-class citizens on the Web of Data. © 2022 Copyright for this pape... 详细信息

关键词： Encoding (symbols)

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Investigation of alternative attention modules in transformer models for remaining useful life predictions: addressing challenges in high-frequency time-series data

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Procedia CIRP 2024年 122卷 85-90页

作者： Eugen Boos Jan Zimmermann Hajo Wiemer Steffen Ihlenfeldt Technische Universität Dresden Fraunhofer Institute for Machine Tools and Forming Technology

Predicting the Remaining Useful Life of a machine components or systems is a pivotal technology in condition-based maintenance and essential for ensuring the reliability and safety in various production-engineering applications. The influx of extensive industrial data has notably enhanced the efficacy of data-driven Remaining Useful Life prediction models, especially deep learning models. One of the promising deep learning model architectures is the Transformer-based model with the Self-Attention mechanism at its core. However, inherent limitation arise when applying Self-Attention to high- frequency time-series data with large window sizes. Due to its high computational complexity, hardware limitations hinder the practical implementation of Transformer with Self-Attention in production-engineering applications. This study looks into the utilization of alternative Attention modules with reduced complexity, making it more applicable to high-frequency time-series data. In order to allow comparability, this study uses the well-known C-MPASS dataset for benchmarking Remaining Useful Life approaches. Although this dataset does not consist of high-frequency data, it demonstrates the usefulness of alternative Attention modules without noteworthy losses in model accuracy.

关键词： Remaining useful life Attention Complexity Transformer Deep learning

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Potential of Radar Based Measuring Systems in Hot Forging 18th

Potential of Radar Based Measuring Systems in Hot Forging

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18th Global Conference on Sustainable Manufacturing, GCSM 2022

作者： Bergmann, M. Dix, M. Wallbaum, T. Selbmannn, R. Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Straße 88 Chemnitz09126 Germany Institute for Machine Tools and Production Processes Chemnitz University of Technology Chemnitz09126 Germany

ISBN: (纸本)9783031288388

Hot forging processes and process chains provide components, which meet highest demands due to mechanical properties. A wide range of applications in different industries like oil and gas, automotive and aviation are based on such processes. As those processes are very productive unfavorable process conditions and unnecessary reject or rework are a strong issues and still not solved for industrial scale production. One key challenge is to generate geometrical information of the workpiece. The geometrical characterization of hot forged parts is usually carried out in cold condition resulting in an extensive time delay to processing. Information about the part geometry during processing and right after processing – in hot condition -- is not accessible. An approach to address this are radar based measuring systems. Those systems have specific characteristics like sufficient accuracy and robustness which qualifies them for measuring tasks under rough conditions typically occurring during forging processes. In the paper, different use cases for the application of radar-based measuring systems are identified and analyses based on laboratory scale experiments. © 2023, The Author(s).

关键词： Radar measurement

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Design, Fabrication and Characterization of a Novel Variable Stiffness Structure for Soft Continuum Robotics

Design, Fabrication and Characterization of a Novel Variable...

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International Joint Conference on Mechanics, Design Engineering and Advanced Manufacturing, JCM 2022

作者： Weisheit, Linda Wockenfuß, Wilhelm Richard Fraunhofer Institute for Machine Tools and Forming Technology IWU Nöthnitzer Straße 44 Dresden01187 Germany

ISBN: (纸本)9783031159275

Soft Robotics made of soft and compliant materials ensure systems with high inherent safety for a safe human-robot collaboration. Thereby current soft robots mostly lack the required stiffness to apply sufficient loads. To ensure inherent safety and at the same time a greater load capacity, structures with adjustable stiffness are required. In this paper, possible approaches for the realization of a switchable stiffness are analyzed and evaluated against the application background of human-oriented soft robotics, which focus mainly on high switching dynamics and high stiffness ratios. A concept for variable stiffness robotic segments based on particle and layer jamming for planar motion is shown, enabling highly dynamic switching between stiff and soft with a bending stiffness ratio K > 100. For this variable stiffness structural component, both the development steps and the characterization methodology are explained. Finally, an outlook on the design of a soft continuum robotic manipulator using three of these variable stiff segments and two tendons for an underactuated motion control of the whole structure is given. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Stiffness

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Experimental setup for long term high-precision static friction tests for clamping systems of rotary tables in cutting machine tools 23

Experimental setup for long term high-precision static frict...

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23rd International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2023

作者： Wieland, Sebastian Zschech, Richard Schneider, Jörg Müller, Jens Edelmann, Jan Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Dresden University of Technology Institute Of Mechatronic Engineering Dresden Germany

ISBN: (纸本)9781998999132

The objective of the scientific investigation is the determination of the coefficient of static friction for clamping systems of rotary tables in cutting machine tools. New developments in this field of research are able to lead to an enhancement in tolerable cutting forces and machine accuracy or to the minimization of the required clamping forces and the constructed space too. In this context the requirement profile of the investigated clamping systems is more than complex. Since they have an immediate influence on the machine accuracy only smallest movements between the friction partners in the range of a few micrometres are tolerable. Furthermore a clamping system needs to withstand more than 100,000 clamping cycles and also braking applications in case of emergency. Against this background an experimental setup consisting of two testing benches was developed. The first testing bench offers the possibility of quick measurements of the coefficient of static friction by a linear movement to investigate a high number of different samples for a selection process. The second test bench in addition offers the possibility of testing the relevant samples by a torsional load for more than 100,000 clamping cycles and in braking applications. In a study the two test benches are validated and compared against each other based on a state of the art clamping system of a tempered steel on the basis of the determined coefficients of static friction. In addition the results of the long term friction experiments and the observed wear are discussed. © 2023 Euspen Headquarters.

关键词： Wear of materials

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Component reuse strategy (CRS) for continuous reinforced thermo-sets enabling circular economy

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Journal of Remanufacturing 2022年第3期12卷 339-355页

作者： von Freeden, Justus Husemann, Alexander Caba, Stefan Fraunhofer Institute or Machine Tools and Forming Technology Chemnitz Germany EDAG Engineering GmbH Fulda Germany

A circular economy, effective technologies for the recycling and reuse of fiber-reinforced plastics (FRPs) are essential to keep these materials attractive for use in various products against the backdrop of stricter environmental regulations. This paper provides an overview of the current state of the art in the recycling and reuse of end-of-life (EOL) fiber reinforced plastic (FRP) products. A significant proportion of EOL FRP products are thermally recycled or used as fillers in the cement industry. Complementary to the existing approaches of structural reuse of FRP is presented in this paper as component reuse strategies (CRS). Both approaches avoid separation or destruction (downgrading) of the composite materials. An application example for the reuse of a carbon-fiber reinforced plastics (CFRP) base frame of an electric vehicle platform is given and analyzed with respect to known design for reuse approaches. The proposed CRS has great potential to complement existing approaches and slow down resource consumption. In addition, extended service life can make CFRP materials more economically attractive. However, further developments are needed as well as the transfer of the principle to other applications. © 2022, The Author(s).

关键词： Automotive Carbon fiber Circular economy Design for reuse Fiber reinforced plastics

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