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machine learning for material characterization with an application for predicting mechanical properties

GAMM Mitteilungen 2021年第1期44卷 e202100003-e202100003页

作者： Stoll, Anke Benner, Peter Data-Mining and Machine Learning Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Computational Methods in Systems and Control Theory The Max Planck Institute for Dynamics of Complex Technical Systems Magdeburg Germany

Currently, the growth of material data from experiments and simulations is expanding beyond processable amounts. This makes the development of new data-driven methods for the discovery of patterns among multiple lengthscales and time-scales and structure-property relationships essential. These data-driven approaches show enormous promise within materials science. The following review covers machine learning (ML) applications for metallic material characterization. Many parameters associated with the processing and the structure of materials affect the properties and the performance of manufactured components. Thus, this study is an attempt to investigate the usefulness of ML methods for material property prediction. Material characteristics such as strength, toughness, hardness, brittleness, or ductility are relevant to categorize a material or component according to their quality. In industry, material tests like tensile tests, compression tests, or creep tests are often time consuming and expensive to perform. Therefore, the application of ML approaches is considered helpful for an easier generation of material property information. This study also gives an application of ML methods on small punch test (SPT) data for the determination of the property ultimate tensile strength for various materials. A strong correlation between SPT data and tensile test data was found which ultimately allows to replace more costly tests by simple and fast tests in combination with ML. © 2021 The Authors. GAMM - Mitteilungen published by Wiley-VCH GmbH.

关键词： machine learning

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Dynamics of a driven harmonic oscillator coupled to pairwise interacting Ising spins in random fields

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Physical Review E 2021年第5期104卷 054212-054212页

作者： Paul Zech Andreas Otto Günter Radons Institute of Physics Chemnitz University of Technology 09107 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 09126 Chemnitz Germany Institute of Mechatronics Reichenhainer Str. 88 09126 Chemnitz Germany

In general we are interested in dynamical systems coupled to complex hysteresis. Therefore as a first step we investigated recently the dynamics of a periodically driven damped harmonic oscillator coupled to independent Ising spins in a random field. Although such a system does not produce hysteresis, we showed how to characterize the dynamics of such a piecewise-smooth system, especially in the case of a large number of spins [Zech, Otto, and Radons, Phys. Rev. E 101, 042217 (2020)]. In this paper we extend our model to spin dimers, thus pairwise interacting spins. We show in which cases two interacting spins can show elementary hysteresis, and we give a connection to the Preisach model, which allows us to consider an infinite number of spin pairs. This thermodynamic limit leads us to a dynamical system with an additional hysteretic force in the form of a generalized play operator. By using methods from general chaos theory, piecewise-smooth system theory, and statistics we investigate the chaotic behavior of the dynamical system for a few spins and also in the case of a larger number of spins by calculating bifurcation diagrams, Lyapunov exponents, fractal dimensions, and self-averaging properties. We find that the fractal dimensions and the magnetization are in general not self-averaging quantities. We show how the dynamical properties of the piecewise-smooth system for a large number of spins differs from the system in its thermodynamic limit.

关键词： Bifurcations Chaos Spin dynamics Chaotic systems Ising model Phase space methods

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Monitoring the Evolution of Dimensional Accuracy and Product Properties in Property-Controlled forming Processes

SSRN

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SSRN 2023年

作者： Stebner, Sophie Charlotte Martschin, Juri Arian, Bahman Dietrich, Stefan Feistle, Martin Hütter, Sebastian Lafarge, Rémi Laue, Robert Li, Xinyiang Schulte, Christopher Spies, Daniel Thein, Ferdinand Wendler, Frank Wrobel, Malte Vasquez, Julian Rozo Dölz, Michael Münstermann, Sebastian Integrity of Materials and Structures RWTH Aachen University Aachen Germany Institute of Forming Technology and Lightweight Components Dortmund University Dortmund Germany Forming and Machining Technology Paderborn University Paderborn Germany Institute for Applied Materials - Material Science Karlsruhe Institute of Technology Karlsruhe Germany Fraunhofer Institute for Casting Composite and Processing Technology Garching Germany Institute of Materials and Joining Technology Otto-von-Guericke University Magdeburg Germany Forming and Machining Processes Technische Universität Dresden Dresden Germany Institute for Machine Tools and Productions Processes Virtual Production Engineering Chemnitz University of Technology Chemnitz Germany Institute of Metal Forming RWTH Aachen University Aachen Germany Institute of Automatic Control RWTH Aachen University Aachen Germany Institute for Production Engineering and Forming Machines Technical University of Darmstadt Darmstadt Germany Institut für Geometrie und Praktische Mathematik RWTH Aachen University Aachen Germany Measurement and Sensor Technology Chemnitz University of Technology Chemnitz Germany Digital Process Engineering Group Institute for Mechanical Process Engineering and Mechanics Karlsruhe Institute of Technology Karlsruhe Germany Materials Test Engineering Dortmund University Dortmund Germany

As recent trends in manufacturing engineering disciplines show a clear development in the sustainable as well as economically efficient design of forming processes, monitoring techniques have been gaining in relevance. In terms of monitoring of product properties, most processes are currently open-loop controlled, entailing that the microstructure evolution, which determines the final product properties, is not considered. However, a closed-loop control that can adjust and manipulate the process actuators according to the required product properties of the component will lead to a considerable increase in efficiency of the processes regarding resources and will decrease postproduction of the component. For most forming processes, one set of component dimensions will result in a certain set of product properties. However, to successfully establish closed-loop property controls for the processes, a systematic understanding of the reciprocity of the dimensions after forming and final product properties must be established. This work investigates the evolution of dimensional accuracy as well as product properties for a series of forming processes that utilize different degrees of freedom for process control. © 2023, The Authors. All rights reserved.

关键词： Process control

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Simulation-based digital twin for the manufacturing of thermoplastic composites 31st

Simulation-based digital twin for the manufacturing of therm...

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31st CIRP Design Conference 2021, CIRP Design 2021

作者： Hürkamp, André Lorenz, Ralf Ossowski, Tim Behrens, Bernd-Arno Dröder, Klaus Technische Universität Braunschweig Institute of Machine Tools and Production Technology Langer Kamp 19b Braunschweig38106 Germany Leibniz Universität Hannover Institute of Forming Technology and Machines An der Universität 2 Garbsen30823 Germany Open Hybrid LabFactory Hermann-Münch-Straße 2 Wolfsburg38440 Germany

The bond strength between a thermoformed fibre reinforced thermoplastic sheet and an injected polymer is the limiting factor for the structural integrity of overmoulded thermoplastic composites. In this contribution, a simulation based digital twin of the thermoforming process is presented. From numerical parametric studies a reduced order model based on Proper Orthogonal Decomposition (POD) is developed. The combination with machine learning methods enables the real-time computation of arbitrary physical reliable temperature fields with sufficient accuracy to be used for design purposes and as inline quality gates. © 2021 Elsevier B.V.. All rights reserved.

关键词： Finite element method

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Comparison of Resistive and Optical Strain Measurement for Early Fracture Detection

Comparison of Resistive and Optical Strain Measurement for E...

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作者： Carabello, Alina Neupetsch, Constanze Werner, Michael Rotsch, Christian Drossel, Welf-Guntram Zajonz, Dirk Chemnitz University of Technology Adaptronics and Lightweight Design in Production Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology Iwu Chemnitz/ Dresden Germany Zeisigwaldkliniken Bethanien Chemnitz Germany

To increase learning success in surgical training, physical simulators are supplemented by measurement technology to generate and record objective feedback and error detection. An opportunity to detect fractures following hip stem implantation early can be measurement of occurring strains on bone surface. These strains can be determined while using strain gauges, digital image correlation (DIC) or photoelasticity. In this research strain gauges and DIC were compared regarding their suitability as strain measurement tools for use in physical simulators. Therefore a testing method was described to replicate the implantation of a hip stem. Testing devices modelled on a realistic prosthesis were pressed into prepared porcine femora in a two-step procedure with a material testing machine. The local strains occurring on bone surface were determined using an optical measurement system for DIC and strain gauges. The initial fractures in the tested femora are located medial-anterior in most cases (73,6%). With increasing indentation depth of the test device, the strains on bone surface increase. Comparing the local strains determined by DIC and strain gauges consistencies in curves are noticeable. Maximal determined strains before fracturing amount to 0,69% with strain gauges and 0,75% with DIC. In the range of the fracture gap, strain gradients are determined by using DIC. However the detected surfaces are of low quality caused by gaps and motion artefacts. The results show strains on bone surfaces for early fracture detection are measurable with strain gauges and DIC. DIC is assessed as less suitable compared to strain gauges. Furthermore strain gauges have greater level of integration and economic efficiency, so they are preferred the use in surgical training simulators. © 2020 by Walter de Gruyter Berlin/Boston 2020.

关键词： Image correlation

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Impact of Cyber-physically enhanced manufacturing on the product requirement documentation in high-tech applications

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Procedia CIRP 2021年 102卷 210-215页

作者： Albrecht Hänel André Seidel Carl Willy Mehling Alexander Dementyev Karol Kozak Rudi Seidel Uwe Teicher Arvid Hellmich Welf-Guntram Drossel Steffen Ihlenfeldt Fraunhofer Institute for Machine Tools and Forming Technology IWU Dresden 01187 Germany Technische Universität Dresden Center for Evidence-based Healthcare Dresden 01307 Germany Technische Universität Chemnitz Institute for Machine Tools and Production Processes Chemnitz 09126 Germany Technische Universität Dresden Institute of Mechatronic Engineering Dresden 01062 Germany

Conventional machining of high-tech parts and components is often associated with complex processes, long lead times and small to medium batch sizes. Obviously, there is great interest to shorten process development periods and increase process reliability. The transformation of conventional machines into cyber-physical production systems (CPPS) promises significant improvements here. In fact, CPPS allows real-time data acquisition and processing, enabling to target integrated process improvement and quality assurance. In the present work, a methodical procedure for structured data aggregation is introduced for a Cyber-physical enhanced machining process while being explained from a high-tech application point of view. This includes data generation, extraction, transfer and storage, data-consolidation, linkage, visualization and interpretation. Finally, the paper illustrates these aspects in terms of the effects on the “digital product requirements” in order to achieve the presented “analytics-ready” data model using the example of a high-tech application.

关键词： Digital Manufacturing System Modelling Process control Cyber-physical production

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VariPath: A Database for Modelling the Variance of Human Pathways in Manual and HRC Processes with Heavy-Duty Robots

VariPath: A Database for Modelling the Variance of Human Pat...

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IEEE International Conference on Robotics and Automation (ICRA)

作者： Mohamad Bdiwi Ann-Kathrin Harsch Paul Reindel Matthias Putz Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz

ISBN: (数字)9781728173955

ISBN: (纸本)9781728173962

Unlike robots, humans do not have constant movements. Their pathways are individually changeable and influenced by circumstances. This paper presents a method to investigate human pathway variations in a real study. In systematically selected tasks, human pathways are examined for 100 participants in manual and human-robot collaboration (HRC) scenarios. As a result, the variations of pathways are presented depending on various features: e.g. in nearly all cases the variance of women's walking pathways is smaller than that of men. VariPath database can be used in any planning process of manual or HRC scenarios to ensure safety and efficiency.

关键词： Legged locomotion Service robots Task analysis Planning Atmospheric measurements Particle measurements

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Reproducibility of modal parameters using different excitation types 26

Reproducibility of modal parameters using different excitati...

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26th International Congress on Sound and Vibration, ICSV 2019

作者： Hensel, Eric Knöfel, Björn Fraunhofer Institute for Machine Tools and Forming Technology Dresden Germany

ISBN: (纸本)9781999181000

Experimental acquisition techniques of modal parameters are well-known topics in the dynamic characterization process of steel structures. The objective is to determine the structure's natural vibration properties, which are eigenfrequencies, corresponding mode shapes and damping. Mostly, the experimentally obtained modal parameters are used to verify numerical models, which can be utilized e.g. for overall system vibration simulations. The modal parameters usually were taken from single measurements and thus, few information about the parameter variances are available. In experimental modal analysis, the choice of the boundary condition (e.g. free or grounded support) as well as the corresponding excitation type (e.g. impulse hammer or shaker) may impact the variance of the obtained modal data. The present article focuses on the differences in reproducibility of modal parameters using an impact hammer and a modal shaker, where measurements are carried out under free/free boundary conditions. The test object is a gear wheel, which first eigenfrequency occurs in a frequency range around 4.6 kHz. During the experimental modal analysis, the frequency response functions are obtained up to 20 kHz. Due to the high frequency range, a 3D Scanning Laser Doppler Vibrometer is used to measure the vibrations velocities in all configurations. In a first test setup, statistical variations of a single gear wheel's modal parameters are analyzed and special attention will be payed on the reproducibility of the excitation force using an automated impulse hammer. In a second step, repeated measurements of modal parameters of one gear wheel are presented followed by a comparison of measurements on three identical gear wheels of one lot. Finally, repeating measurements are carried out using a modal shaker for system excitation and the corresponding modal parameters are compared to the results obtained using an impact hammer © Proceedings of the 26th International Congress on Sound and V

关键词： Modal analysis

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Digital innovation hubs for robotics - TRINITY approach for distributing knowledge via modular use case demonstrations 8

Digital innovation hubs for robotics - TRINITY approach for ...

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8th CIRP Conference of Assembly technology and Systems, CATS 2020

作者： Lanz, Minna Reimann, Jan Ude, Aleš Kousi, Niki Pieters, Roel Dianatfar, Morteza Makris, Sotiris Tampere University Tampere Finland Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Jožef Stefan Institute Ljubljana Slovenia University of Patras Patras Greece

Robots are no longer stand-alone systems on the factory floor. The demand for industrial robots (market) is anticipated to be growing to 65 billion euros by the year 2023. Within all areas of robotics, the demand for collaborative and more flexible systems is rising as well. The level of desired collaboration and increased flexibility will only be reached if the systems are developed as a whole, e.g. perception, reasoning and physical manipulation. The rising need for collaborative robots in the automation industry is acting as a driver for this market and is expected to serve as a market opportunity for future growth. However, at the same time especially smaller companies have difficulties to formulate a concrete vision and strategies for the uptake of robotics, finding skilled workforce to develop and deploy the robot systems and/or work in the manufacturing industry. A number of Digital Innovation Hubs (DIHs) have been developed to enhance the knowledge and technology transfer from laboratories to factory floors, mitigating the skills gap and supporting the formulation of innovation ecosystems with the specific focus on small and medium-sized companies around Europe. The main aim of this paper is to introduce the concept and approach taken in H2020 TRINITY-project that aims to develop a Robotics Innovation Hub focused on Agile Production. The paper will introduce the concept and technical approach of the project, and discusses the preliminary results, challenges and opportunities of these kind of DIHs. © 2020 The Author(s).

关键词： Industrial robots

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New VDI guideline 2248 - An overview

New VDI guideline 2248 - An overview

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International Conference on Shape Memory and Superelastic Technologies 2019, SMST 2019

作者： Böhm, Andrea Fraunhofer Institute for Machine Tools and Forming Technology Dresden Germany

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