DigitalNachhaltigF: Maschinenbau und MechatronikI: Fraunhofer AWZ CTMTZeitschriftenartikel
A. Stock, Gabriel Herl, T. Sauer, Jochen Hiller
Edge-preserving compression of CT scans using wavelets
Insight - Non-Destructive Testing and Condition Monitoring (The British Institute of Non-Destructive Testing), vol. 62, no. 6, pp. 345-351
2020
DOI: 10.1784/insi.2020.62.6.345
Abstract anzeigen
This work addresses the subject of efficient storage of computed tomography (CT) data with an emphasis on the quality of surfaces. Industrial dimensional metrology often requires high measurement accuracy and it is shown that this is retained using wavelet-based compression methods. The applied techniques include a tensor product wavelet transform and soft wavelet shrinkage. In these tests, performed on real objects, dimensional CT measurements of compressed and uncompressed volumes were compared. The necessary storage space was reduced significantly with a negligible loss of accuracy. The storage space required for a multi-sphere phantom was decreased to 4.7% (from 638 MB to 30 MB), with an average deviation below 1 μm from the original volume.
DigitalNachhaltigExternZeitschriftenartikel
Anton Schmailzl, Johannes Käsbauer, J. Martan, P. Honnerová, F. Schäfer, Maximilian Fichtl, T. Lehrer, L. Prušáková, J. Tesař, J. Skála, M. Honner
Measurement of core temperature through semi-transparent polyamide 6 using scanner-integrated pyrometer in laser welding
International Journal of Heat and Mass Transfer, vol. 146, no. January
2020
DOI: 10.1016/j.ijheatmasstransfer.2019.118814
Abstract anzeigen
Predicting the core temperature during welding is an ambitious aim in many research works. In this work, a 3D-scanner with integrated pyrometer is characterized and used to measure the temperature during quasi-simultaneous laser transmission welding of polyamide 6. However, due to welding in an overlap configuration, the heat radiation emitted from the joining zone of a laser transmission weld has to pass through the upper polymer, which is itself a semi-transparent emitter. Therefore, the spectral filtering of the heat radiation in the upper polymer is taken into account by calibrating the pyrometer for the measurement task. Thermal process simulations are performed to compare the temperature field with the measured temperature signal. The absorption coefficients of the polymers are measured, in order to get precise results from the computation. The temperature signals during welding are in good agreement with the computed mean temperature inside the detection spot, located in the joining area. This is also true for varying laser power, laser beam diameter and the carbon black content in the lower polymer. Both, the computed mean temperature and the temperature signal are representing the core temperature. In order to evaluate the spatial sensitivity of the measurement system, the emitted heat radiation from both polymers is calculated on basis of the computed temperature field. Hereby it is found, that more than 90 percent of the detected heat radiation comes from the joining area, which is a crucial information for contact-free temperature measurement tasks on semi-transparent polymers.
DigitalNachhaltigExternZeitschriftenartikel
Johannes Käsbauer, Anton Schmailzl, J. Prehm, T. Loose, S. Hierl
Simulation of Quasi-Simultaneous Laser Transmission Welding of Plastics: Optimization of Material Parameters in Broad Temperature Range
Procedia CIRP, vol. 94, pp. 737-741
2020
DOI: 10.1016/j.procir.2020.09.136
Abstract anzeigen
Thermo-mechanical simulation offers great opportunities to optimize welding processes of plastics. For realistic simulation, the temperature dependent mechanical properties need to be implemented from ambient temperature to temperatures above the flow temperature. Standard test methods are insufficient for characterization in the entire temperature range because close to the flow temperature the material is too soft for tensile tests and too stiff for rheometry. Therefore, an optimization strategy is developed, that determines unknown material parameters by testing in welding simulations. The unknown parameters are iteratively adjusted to minimize the mismatch between computed and measured set-paths. Thus, important process characteristics are calculated realistically, enabling the computer aided assessment of the weld quality.
NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH TeisnachBeitrag (Sammelband oder Tagungsband)
Sebastian Sitzberger, Johannes Liebl, Christian J. Trum, Rolf Rascher
Concept of a two-part clamping system for lenses in optical metrology
Proceedings of SPIE 11478 (Seventh European Seminar on Precision Optics Manufacturing [8 July 2020; Teisnach]), Bellingham, WA, USA
2020
DOI: 10.1117/12.2566547
Abstract anzeigen
The developed concept represents a universally applicable clamping system designed to fit in any measuring machine with
any measuring principle. The design ensures that, as long as the lens remains clamped, the measurement results are
reproducible. Form errors due to tension remain constant across all measuring and processing steps. The version presented
in this paper was developed especially for small lenses in the diameter range up to 40 mm. On the one hand, the design
allows for fast measurement of loose lenses. On the other hand, the device can also be used for measurement comparisons,
since lenses can also be mounted permanently. In the following, the concept and first results of measurement tests are
presented.
NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenS: IPH TeisnachBeitrag (Sammelband oder Tagungsband)
Armin Reif, Sebastian Sitzberger, Rolf Rascher
Cutting high-performance materials with ultrasonically modulated cutting speed
Proceedings of SPIE 11478 (Seventh European Seminar on Precision Optics Manufacturing [8 July 2020; Teisnach]), Bellingham, WA, USA
2020
DOI: 10.1117/12.2565757
Abstract anzeigen
The continuing trend towards lightweight construction and the associated machining rates of up to 95 % lead to an
increased use of high-performance materials. The ever growing demands on the strength and quality of components and
the associated use of materials which are hard to machine require the further development of new, economical machining
techniques. In ultrasonic-assisted machining, an additional high-frequency vibration is superimposed on the conventional
machining process. The vibration of the tool is usually excited axially or longitudinally to the workpiece, i.e. vertical to
the cutting direction. An additional vibration overlay around the rotation axis (torsional) of the tool is also possible. This
generates a vibration overlay in the cutting direction. The vibration initiation causes vibration amplitudes in the range of a
few micrometers at the tool cutting edge. This leads in turn to a high-frequency change in the cutting speed or feed rate.
Overall, an additional torsional vibration overlap can further reduce cutting forces, increase tool life and improve
workpiece quality.
In order for a grinding tool to generate a torsional vibration, a special tool was required that had to be designed by
simulation. The formation of a torsional vibration was achieved by helical slots in the sonotrode. Depending on the angle
of rotation and the length of the slots, a part of the axial vibration is converted into a torsional vibration by an axial
excitation of the sonotrode. The aim in designing the slots was to achieve the highest possible vibration amplitude.
Following the simulation, the slots were inserted into the tool in the corresponding optimum geometric position.
Afterwards, the specially designed grinding tool was validated by machining the brittle-hard glass-ceramic material
Zerodur. The first test results with the torsionally vibrating tool are presented in the following.
NachhaltigF: Elektrotechnik und MedientechnikI: IQMAZeitschriftenartikel
H. Fan, Y. Zhang, D. Liu, C. Niu, L. Liu, W. Ni, Y. Xia, Z. Bi, Günther Benstetter, G. Lei
Tensile stress-driven cracking of W fuzz over W crystal under fusion-relevant He ion irradiations
Nuclear Fusion, vol. 60, no. 4
2020
DOI: 10.1088/1741-4326/ab71bb
Abstract anzeigen
Although W fuzz is formed in the divertor region of the fusion reactor, no theory may clearly explain the W fuzz growth mechanism. In this study, we observe the growth process of W fuzz over W crystal under ITER-relevant He ion irradiations. We propose the tensile stress-driven cracking of nano-structured fuzz during the initial growth of W fuzz. We demonstrate that the existence of tensile stress is due to the swelling of He nano-bubbles in the fuzz. After this cracking, the W fuzz breaks away from the planar network and grows over the W surface, where the micro-stress in the W surface layer acts as the driving force.
NachhaltigF: Angewandte Naturwissenschaften und WirtschaftsingenieurwesenZeitschriftenartikel
Thomas Stirner, David Scholz, J. Sun
Convergence of surface energy calculations for various methods: (001), (012), (100) hematite and the applicability of the standard approach
Journal of Physics: Condensed Matter, vol. 32, no. 18
2020
DOI: 10.1088/1361-648X/ab6f88
Abstract anzeigen
Three different methods for the calculation of the surface energy, namely the standard approach, the Boettger relation and the linear-fit method, are applied to the (0 0 1), (0 1 2) and (1 0 0) hematite surfaces. The standard approach was previously shown to suffer from a divergence problem, and the Boettger relation was shown to exhibit quantum size effects. While the linear-fit method, in general, leads to a good convergence behavior of the surface energy, the questions arise whether the relative order of the calculated surface energies depends on the chosen calculation method, and whether there is any merit at all in employing the standard approach. The present work investigates these questions with hematite as a benchmark material system. The simulations show that, for the surface facets and slab thicknesses studied here, the relative order of the surface energies is unaffected by the chosen calculation method. A regime is found where the three methods are in reasonably good agreement with respect to the obtained surface energies. Finally, a procedure is put forward to extract meaningful surface energy values from the standard approach.
MobilNachhaltigF: Angewandte InformatikS: TC Plattling MoMoBeitrag (Sammelband oder Tagungsband)
Markus Eider, Andreas Berl
Requirements for prescriptive recommender systems extending the lifetime of EV batteries
Proceedings of the 2020 10th International Conference on Advanced Computer Information Technologies (ACIT) [September 6-8, 2020; Deggendorf]
2020
DOI: 10.1109/ACIT49673.2020.9209011
Abstract anzeigen
Lithium-ion batteries in electric vehicles are subject to degradation, which is strongly influenced by the actions of vehicle users. Hereby, inexperienced users can cause the battery to reach its end of life state earlier than average. For this reason, this paper proposes the concept of a prescriptive recommender system that supports users in planning their utilization actions. The paper identifies functionalities of decision support systems relevant to extend the lifetime of electric and electronic systems. This allows to determe generic functional and non-functional requirements for prescriptive recommender systems. Further, the derived requirements are discussed in connection to the practicability of a prescriptive recommender system.
DigitalNachhaltigF: Angewandte InformatikS: TC FreyungVortrag
Melanie Piser, Sebastian Wöllmann
Digitale Partizipation als Prozessbeschleuniger für öffentliche Projekte - Bürgerbeteiligung im Projekt ALIA in der Gemeinde Weiherhammer
Posterpräsentation
INUAS International Conference 2020: Ressourcen - Zeit, Raum, Energie, Material (INUAS-Konferenzreihe - Urbane Transformationen: Wohnen, Ressourcen, Öffentliche Räume), München
2020
DigitalNachhaltigF: Angewandte InformatikS: TC FreyungVortrag
Melanie Piser, Sebastian Wöllmann
Digitale Partizipation von FörderschülerInnen zur sozial und materiell nachhaltigen Gestaltung des Baubestands - Chancen digitaler Beteiligung von SchülerInnen am Beispiel der Schulhaussanierung des Rupert-Egenberger-Förderschulzentrums in der Stadt Amberg/Opf.
Posterpräsentation
INUAS International Conference 2020: Ressourcen - Zeit, Raum, Energie, Material (INUAS-Konferenzreihe - Urbane Transformationen: Wohnen, Ressourcen, Öffentliche Räume), München
2020
DigitalNachhaltigF: Angewandte InformatikS: TC FreyungVortrag
Melanie Piser, Sebastian Wöllmann
Digitale Partizipation von FörderschülerInnen zur sozial und materiell nachhaltigen Gestaltung des Baubestands - Chancen digitaler Beteiligung von SchülerInnen am Beispiel der Schulhaussanierung des Rupert-Egenberger-Förderschulzentrums in der Stadt Amberg/Opf.
INUAS International Conference 2020: Ressourcen - Zeit, Raum, Energie, Material (INUAS-Konferenzreihe - Urbane Transformationen: Wohnen, Ressourcen, Öffentliche Räume), München
2020
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