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Aufsatz
An extended constitutive model for nonlinear reversible ferromagnetic behaviour under magnetomechanical multiaxial loading conditions
(2017-02-01)
A constitutive modelling of ferromagnetic materials under combined magnetomechanical multiaxial loading with different boundary conditions and a finite element implementation are presented. The phenomenologically motivated model is capable of predicting magnetisation, strain, and stress and is thus suitable, e.g., for applications in multiferroic composites. The approach covers a reversible nonlinear behaviour as it is observed, e.g., in cobalt ferrite and other soft magnetic alloys. Various examples demonstrate the ...
Aufsatz
Grundsatzfragen der Abwärmenutzung
(2017-04)
In der Diskussion zum Thema Energieeffizienz wird regelmäßig über Abwärmenutzungstechnologien (AbWT) wie Sorptionskältemaschinen, Organic-Rankine-Cycle-Prozesse (ORC) oder Wärmepumpen diskutiert. Diese sollen eine praktikable Nutzung von Abwärme ermöglichen. Im Sinne eines Plug & Play Systems erfolgt die Ankopplung an eine Abwärmequelle und eine andere Nutzenergieform wie Strom, Kälte oder Hochtemperaturwärme kann an geeigneter Stelle wieder in den Prozess integriert werden. Doch wie lassen sich Abwärmequellen und ...
Aufsatz
Sektorkopplung Prozesswärme / Strom in der deutschen Industrie
(2018)
Sektorkopplung bedeutet die Verbindung des Elektrizitäts- mit dem Wärme- und Mobilitätssektor. Während der Ausbau der erneuerbaren Energien (EE) im Strombereich erhebliche Fortschritte, bis zu einem Anteil von über 30 %, erzielt hat, ist im Wärme- (ca. 13 %) und Mobilitätssektor (ca. 5,1 %) der Anteil in den letzten zehn Jahren fast konstant geblieben. Die Elektrifizierung dieser Anwendungsbereiche soll den Anteil an erneuerbarer Energie erhöhen und somit zu einer Reduzierung von Treibhausgasen beitragen. Abbildung ...
Aufsatz
Mixed-mode crack tip loading and crack deflection in 1D quasicrystals
(2016)
Quasicrystals (QC) are a new class of materials besides crystals and amorphous solids and have aroused much attention of researchers since they were discovered. This paper presents a generalized fracture theory including the J-integral and crack closure integrals, relations between J1, J2 and the stress intensity factors as well as the implementation of the near-tip stress and displacement solutions of 1D QC. Different crack deflection criteria, i.e. the J-integral and maximum circumferential stress criteria, are ...
Aufsatz
Integration of Heat Pump Storage Systems in Manufacturing Systems via Data Farming and Monte Carlo Simulation
(2019)
The electrification of industrial energy demand is essential for effective climate protection and a successful energy transition. In production systems with fluctuating heating and cooling demands, heat pumps can make a significant contribution to electrification and increased efficiency in a demand-oriented production with automated standby operation. In order to dimension a suitable heat pump storage system, well-founded statistical information about the production system is required. For the creation of stochastic ...
Aufsatz
Constitutive modeling of nonlinear reversible and irreversible ferromagnetic behaviors and application to multiferroic composites
(2016-03-10)
The coupling of magnetic and mechanical fields due to the constitutive behavior of a material is commonly denoted as magnetostrictive effect. The latter is only observed with large coupling coefficients in ferromagnetic materials, where coupling is caused by the rotation of the domains as a result of magnetic (Joule effect) or mechanical (Villari effect) loads.
However, only a few elements (e.g. Fe, Ni, Co, and Mn) and their compositions exhibit such a behavior. In this article, the constitutive modeling of nonlinear ...
Aufsatz
Energy Efficiency Measures for Batch Retort Sterilization in the Food Processing Industry
(2016)
The purpose of this study is to highlight the energy saving potentials of a batch retort sterilization process operated by steam and to develop concepts for improving its energy efficiency. By using the methodical approach of the Onion Diagram and the recovery of low grade heat sources, four comprehensive improved energy efficiency concepts have been developed. Two concepts increase the initial product temperature resulting in lower transient steam consumption rates and a decreased energy demand. The other two options ...
Aufsatz
Efficient Spatial and Temporal Modelling of Material Temperatures within Self-reinforced Polypropylene Sheets during IR Radiation
(2013-07-20)
Polymer composites of self-reinforced fibres and a matrix composed of the same plastic material display an outstanding mechanical performance and an excellent recyclability. Hence, these materials are suitable for many practical applications. One disadvantage, however, is the narrow processing window that is caused by a strong pressure and temperature sensitivity of the self-reinforced fibres. In this paper, an approach to efficiently model the spatial and temporal temperature evolution is presented. Advanced empirical ...