A method for communication between user materials during runtime in ABAQUS®

The application of the Finite Element Method (FEM) has developed considerably in recent decades. While in the early days of the FEM only linear-elastic material models were available in commercial Finite Element (FE) programs, today non-linear and also damage-considering material models are offered. But even these are often not capable of correctly representing the complex material behaviour of modern composite materials. Therefore, FE programs often provide the users with the option of integrating their own material models into the simulation. These programs, often called "user subroutines" or "user materials", represent an intensively researched area in the simulation of material behaviour, which is reflected in the large number of publications on such developments (exemplarily see [1-14]). These material models often require a large amount of data values if they are introduced within the simulation model by finite elements [2]. Especially in the field of composites there is a need to use a separate "user material" for each constituent material. Since there is a mutual interaction between the components in real composites, it is obvious that this interaction must also be represented The 8th European Congress on Computational Methods in Applied Sciences and Engineering ECCOMAS Congress 2022 5 – 9 June 2022, Oslo, Norway PHILIP F. ROSE, LUKAS MÜNCH, MARKUS LINKE AND PETER MIDDENDORF 2 between the material models within a simulation in order to make accurate predictions about the material behaviour. To enable such an interaction between different material models in a simulation, a communication during runtime is required in which additionally needed data from the surrounding elements is exchanged between the user materials. In this paper, a method is presented to enable such information exchange during simulation runtime in the commercial FE software ABAQUS/CAE 2019 (Dassault Systèmes, Vélizy-Villacoublay, France) using external databases as well as structured global arrays and some built-in functions of the software. This allows the simultaneous application of several advanced user material models within one simulation and enable them to communicate during runtime, resulting in the possibility of making high accurate simulations of composite materials

Fabrication of chitosan-flax composites with differing molecular weights and its effect on mechanical properties

An aqueous fabrication method is investigated for a composite reinforced with chitosan and flax fibers. The composite is characterized structurally, mechanically and chemically. A strong influence of molecular weight (MW) is identified on the composite properties. A strong fiber-matrix interface, which is associated with porosity and effective fiber impregnation, is achieved by applying low molecular weight (LMW) solution followed by casting using LMW or medium molecular weight (MMW) solution. Porosity is analyzed using μ-CT analysis. Increasing porosity with increasing molecular weight results in a decline of the tensile and flexural properties of the composites. The chitosan-flax composites have a low density compared to synthetic and natural fiber composites, which is a competitive advantage as a replacement material for particle board or plyboard in suspended ceilings, furniture compartments, sports or leisure equipment. A multiscale simulation is carried out to compute the directional effective elastic properties and predicts a potential 21% improvement of the tensile modulus if the process is optimized. This work shows the potential of chitosan-flax composites as a sustainable green material with an aqueous fabrication procedure and useful mechanical properties

Influence of the interfaces on the anisotropic magnetoresistance of Ni/Co multilayers

3 pages, 5 figures.-- PACS: 75.70.Cn; 73.61.At; 73.50.JtAnisotropic magnetoresistance in Ni is found to increase abruptly when Co impurity layers are inserted. Some experiments carried out in different Ni/Co multilayers indicate that interfaces are responsible for the magnetoresistance enhancement.Peer reviewe

Medien-Kanzler gegen Kompetenz-Herausforderer : Die mediale Auseinandersetzung zwischen Gerhard Schröder und Edmund Stoiber unter besonderer Berücksichtigung der TV-Duelle

Bei der Bundestagswahl 2002 standen sich die Spitzenkandidaten der beiden großen Parteien erstmals in zwei Fernsehduellen gegenüber. Die Fokussierung auf die Kanzlerkandidaten der großen Parteien stellte dabei eine Neuheit dar. Die TV-Duelle waren mit großen Aufmerksamkeits- und Wahrnehmungschancen verbunden, die weit über beide TV-Sendungen hinaus auch auf andere Medienformate ausstrahlten. Die vorliegende Arbeit beschreibt Einflussfaktoren auf die Wahlentscheidung und zentrale Ansätze der Wahlforschung und stellt dabei den Faktor Medienberichterstattung ins Zentrum der Untersuchungen. Im Dreieck der politischen Kommunikation (Politiker, Medien und Wähler) spielen die Medien eine Schlüsselrolle. In einem Kapitel zu Kampagnentypen und Medienformaten wird die spezielle Kommunikationssituation im Wahlkampf beleuchtet. Zu den TV-Duellen liegen eine Reihe inhaltsanalytischer Studien vor. Im Rahmen des analytischen Teils wurden diese Studien vorgestellt und zu einer Übersicht zusammengefasst. Den Schwerpunkt des analytischen Teils bildet die gesprächsanalytische Untersuchung der TV-Duelle. Sie leistet einen Beitrag zur qualitativen Erforschung der Wahlkampfkommunikation und ist in insgesamt vier Teilschritte untergliedert: 1. Diskutierte Themen der TV-Duelle 2. Interaktions- und Argumentationsstrategien der Kandidaten und der Moderatoren 3. Aktivierung der Faktoren der Wahlentscheidung durch kommunikative Appelle. Beim letzten Analyseschritt wird ein Wechsel zur Rezipientenperspektive vollzogen. Als Analysegrundlage diente die Real-Time-Response-Befragung der Bamberger Forscher Faas und Maier, die im Rahmen ihres Projektes insgesamt 141 Probanden während der Duelle zur Wahrnehmung der Kandidaten befragten und ein sekundengenaues Beurteilungsraster aus negativen und positiven Urteilen dokumentierten: 4. Stärken- und Schwächen-Analyse Die Starken- und Schwächen-Analyse ermöglicht Aussagen über Erfolg bzw. Misserfolg der kommunikativen Strategien beider Kontrahenten. Um zentrale sprachliche Handlungskategorien zu belegen, wurden Transkriptionen angefertigt und anschließend zu Rastern komprimiert. Dabei wurden sprachliche Handlungen der Kontrahenten und Moderatoren, daraus resultierende sprachliche Handlungsmuster und gesprächsstrategische Zielsetzungen der Kontrahenten bzw. Moderatoren berücksichtigt

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principle calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file