Refine
Year of publication
Document Type
- Article (reviewed) (686) (remove)
Keywords
- Dünnschichtchromatographie (17)
- Adsorption (11)
- Metallorganisches Netzwerk (9)
- Ermüdung (8)
- Lithiumbatterie (8)
- Plastizität (8)
- Simulation (8)
- 3D printing (7)
- Energieversorgung (7)
- Götz von Berlichingen (7)
Institute
- Fakultät Maschinenbau und Verfahrenstechnik (M+V) (286)
- Fakultät Elektrotechnik und Informationstechnik (E+I) (bis 03/2019) (145)
- Fakultät Elektrotechnik, Medizintechnik und Informatik (EMI) (ab 04/2019) (128)
- INES - Institut für nachhaltige Energiesysteme (108)
- Fakultät Wirtschaft (W) (90)
- POIM - Peter Osypka Institute of Medical Engineering (29)
- ivESK - Institut für verlässliche Embedded Systems und Kommunikationselektronik (25)
- Fakultät Medien (M) (ab 22.04.2021) (19)
- Fakultät Medien und Informationswesen (M+I) (bis 21.04.2021) (14)
- IfTI - Institute for Trade and Innovation (13)
Open Access
- Open Access (276)
- Closed Access (243)
- Gold (68)
- Closed (67)
- Hybrid (24)
- Diamond (19)
- Bronze (3)
- Grün (2)
In the present paper, the influence of locally varying microstructures in case of an AlSi12 cast aluminium alloy is investigated by means of extracting the test pieces from different removal positions and low cycle fatigue tests. The temperature-dependent damage mechanisms, the material specific defect types, sizes and their influence on the fatigue properties of two AlSi7 and AlSi12 cast aluminium alloys are studied. An extreme value statistics methodology is applied to predict maximum defect sizes expected in a critical surface volume from two-dimensional metallographic micrographs. A damage map for the AlSi12 cast aluminium alloy is presented explaining the influence of the temperature- and load-dependent damage mechanisms on the observed isothermal and thermomechanical lifetime behavior.
In this work, the influence of superimposed high cycle fatigue on the LCF/HCF and TMF/HCF lifetime is investigated for two cast aluminium alloys of the types AlSi7 and AlSi12. The replica technique is used to examine the short crack growth behavior under pure LCF and LCF/HCF loading. The observed short crack growth evolution explains the observed lifetime reduction with increasing HCF amplitudes.
Detailed material investigations of the fatigue behavior of two cast aluminium alloys used in combustion engines are presented. The network of intermetallic phases of both aluminium alloys is characterized by means of detailed energy dispersive X-ray spectroscopy. In order to investigate the temperature-dependent fatigue behavior of the materials, tensile, low cycle and thermomechanical fatigue tests are performed over a wide temperature and loading range. The influence of the temperature dependence on the experimental results is discussed.
Digitale Lernszenarien in der Hochschullehre. Bedeutung und Funktion aus Sicht von Studierenden
(2021)
Bedingt durch die Coronapandemie wurde in den Informatikkursen Software Engineering und Computernetze an der Hochschule Offenburg ein Lernsetting entwickelt, das mehrere digitale Lernszenarien (Online-Sessions, Lernvideos, Wikis, Quiz, Foren und die selbst entwickelte Lernplattform MILearning) integriert. Im Wintersemester 2020/2021 fand eine Evaluierung statt, um den Einsatz der unterschiedlichen digitalen Lernszenarien in der aktuellen Situation zu bewerten und um zu entscheiden, welche Lernszenarien sinnvoll für einen Einsatz nach der Pandemie sind. Aus dem Blickwinkel des Didaktischen Designs spielen dabei die Eignung der Szenarien für die Wissensvermittlung, die Aktivierung der Studierenden und die Betreuung bei Fragen und Problemen eine wichtige Rolle. Die Ergebnisse zeigen, dass Studierende das Lernsetting intensiv nutzen und die angebotenen digitalen Lernszenarien lernförderlich kombinieren.
Background: This paper presents a conceptual design for an anthropomorphic replacement hand made of silicone that integrates a sensory feedback system. In combination with a motorized orthosis, it allows performing movements and registering information on the flexion and the pressure of the fingers.
Methods: To create the replacement hand, a three-dimensional (3D) scanner was used to scan the hand of the test person. With computer-aided design (CAD), a mold was created from the hand, then 3D-printed. Bending and force sensors were attached to the mold before silicone casting to implement the sensory feedback system. To achieve a functional and anthropomorphic appearance of the replacement hand, a material analysis was carried out. In two different test series, the properties of the used silicones were analyzed regarding their mechanical properties and the manufacturing process.
Results: Individual fingers and an entire hand with integrated sensors were realized, which demonstrated in several tests that sensory feedback in such an anthropomorphic replacement hand can be realized. Nevertheless, the choice of silicone material remains an open challenge, as there is a trade-off between the hardness of the material and the maximum mechanical force of the orthosis.
Conclusion: Apart from manufacturing-related issues, it is possible to cost-effectively create a personalized, anthropomorphic replacement hand, including sensory feedback, by using 3D scanning and 3D printing techniques.
Die vorliegende Arbeit gibt einen Überblick über das Verhältnis zwischen Nutzen und Einschränkungen eines frühneuzeitlichen Riefelharnisches auf die Biomechanik des Menschen. Zu den zentralen Ergebnissen gehört, dass die Rüstung eine gewisse Einschränkung der Beweglichkeit bringt, jedoch durch verschiedene mechanische Konzepte versucht wurde, diese größtmöglich zu minimieren. Besonders das sogenannte Geschübe stellt hierbei einen Kompromiss zwischen Beweglichkeit und Schutzfunktion dar und findet vor allem im Bereich der Gelenke Anwendung. Steife Strukturen werden an Stellen eingesetzt, die kaum Bewegungsfreiheit fordern. Zu diesen Bereichen gehören beispielsweise der Brustkorb oder obere Teile des Rückens. Der Vorteil der steiferen Teile der Rüstung ist ihre erhöhte Schutzfunktion, die ein geringeres Verletzungsrisiko mit sich bringt.
In this paper, the Bauschinger effect and latent hardening of single crystals are assessed in finite element calculations using a single crystal plasticity model with kinematic hardening. To this end, results of cyclic micro-bending experiments on single crystal Alloy 718 in different crystal orientations (single slip and multi slip) with respect to the loading direction are used to determine the slip system related material properties of the single crystal plasticity model. Two kinematic hardening laws are considered: a kinematic hardening law describing latent hardening and a kinematic hardening law without latent hardening. For the determination of material properties for both hardening laws, a gradient-based optimization method is used. The results show that the different strength levels observed for micro-bending tests on different crystal orientations can only be described with latent kinematic hardening well, whereas the pronounced Bauschinger effect is described well by both kinematic hardening laws. It is concluded that cyclic micro-bending experiments on single crystals using different crystal orientations give an appropriate data base for the determination of the slip system related material properties of the single crystal plasticity model with latent kinematic hardening.
Cyclic micro-bending tests on fcc single crystal Ni-base Alloy 718 cantilevers with different crystal orientations were performed to analyze the influence of activated slip systems on dislocation plasticity, latent hardening and the Bauschinger effect. The investigations indicate that plasticity in single crystal micro-cantilevers is significantly influenced by two phenomena - dislocation interaction and dislocation pile-up at the neutral plane. Both phenomena occur at the same time. Their ratio seems to be determined by the activated slip systems. Slip trace analysis indicates that the activation of only one slip system leads to a strong localization of plasticity to a limited number of parallel slip bands. This results in low dislocation interaction and consequently pronounced pile-ups at the neutral plane. In multi slip orientation, the second slip system leads to activation of significantly more dislocation sources, causing a much earlier and more homogeneous elastic-plastic transition zone. In stress-strain hysteresis loops during bending, pronounced dislocation interaction in multi slip orientation leads to a more pronounced latent hardening. The results suggest that on a microstructural length scale, plasticity behavior is strongly affected by activated slip systems, which determine local dislocation phenomena. Based on the results presented in this paper, a finite element analysis of latent hardening and the Bauschinger effect using a single crystal plasticity model with latent kinematic hardening is presented in Part II.
Die Rolle des Aufsichtsrats wird zunehmend als eine strategische charakterisiert, ohne dies jedoch näher zu erläutern. Die aktuelle Diskussion zeigt, dass daraus Unschärfen in der Abgrenzung zur Rolle des Vorstands resultieren. In dem Beitrag wird die Rolle des Aufsichtsrats im Rahmen strategischer Entscheidungen präzisiert.
As PV enters the terawatt era, reliability, sustainability and low carbon footprint of solar modules are key requirements. The N.I.C.E.TM technology from Apollon Solar is a good candidate for significant improvements in these areas. As the second-generation pilot line is now functional with IEC certification underway, we present a holistic assessment of N.I.C.E.TM technology compared with conventional module technology with encapsulant. This includes electrical performance and cost/consumables, reliability, and degradation mechanisms as well as sustainability aspects. In addition, the new generation of N.I.C.E.-wire modules are presented that use thin round Cu wires instead of flat ribbons for interconnection. This candidate technology for an alternative to the Smart Wire Connection Technology (SWCT) is investigated experimentally as well as via numerical simulations.