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Aufsatz
Microscale-Motivated Continuum Damage Simulations of Brittle Ceramics under Thermomechanical Loading
(2016-05-02)
Two approaches towards modeling damage in a brittle material caused by thermomechanical loading are presented.
Bothrelyonmicrocrack growth, in the first case in ahomogeneousmatrix, in the second one at grain boundaries.Two-scale simulations e.g. of thermal shocks applied to single-phase or layered structures are performed in connection with the finite element method. Damage and crack patterns are predicted just as quantities like residual strength or critical temperature jumps.
Teil eines Buches
Anforderungsklassifizierung in der Fahrdynamik und Fahrerassistenz als Grundlage einer kundenorientierten Produktqualität und Kundenzufriedenheit
(kassel university press, 2016)
Die BMW Group zählt zu den weltweit führenden Herstellern von Premiumprodukten und Anbietern von Mobilitätsdienstleistungen in der Automobilindustrie. Durch zunehmende Qualitätsansprüche der Kunden gewinnt auch die Anforderungsklassifizierung an Bedeutung. Gerade in Zeiten steigenden Wettbewerbsdrucks und kürzeren Innovationszyklen ist eine genaue Kenntnis der kundenseitigen Anforderungsmerkmale und deren Auswirkungen auf die produktbezogene Qualitätswahrnehmung und Kundenzufriedenheit von großer Bedeutung. Die ...
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
Total Site Utility Systems Optimisation for Milk Powder Production
(2016)
This study applies the Total Site Heat Integration method, in conjunction with a detailed process and utility model, to investigate three methods to increase the energy efficiency of the utility supply system for milk powder production. Sequentially explored opportunities are: (1) increasing boiler efficiency through condensing economisers, (2) waste heat recovery from the chiller unit, and (3) Combined Heat and Power (CHP) for electricity production. The basis for the analysis is the anticipated future milk powder ...
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
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
Optimal Energy Supply Structures for Industrial Sites in Different Countries Considering Energy Transitions: A Cheese Factory Case Study
(2016)
This present study focuses on analysing the most efficient utility energy supply structure in terms of primary energy efficiency, carbon emissions and energy costs. In the German dairy industry, separate conversion with gas fired steam boiler, and cooling with ammonia chillers are the-state-of-the-art technologies. It is attractive due to its robustness and low investment costs. But given the ongoing energy transition to renewable energy, opportunities to reduce emissions will become increasingly important. There are ...
Dissertation
Konzeption, Implementierung und Anwendung eines automatisierten aerothermodynamischen Vorentwurfsprozesses für Axialturbinen
(2016-07-06)
In dieser Arbeit wird ein Prozess für den frühen aerothermodynamischen Entwurf von Axialturbinen konzipiert und durch Kopplung einzelner Computerprogramme im DLR Göttingen realisiert. Speziell für die Erstauslegung von Geometrien und die Vorhersage von globalen Leistungsdaten beliebiger Axialturbinen wurde ein neues Programm erzeugt. Dessen effiziente Anwendung wird mit einer zu diesem Zweck konzipierten grafischen Entwurfsumgebung ausgeführt. Kennzeichnend für den Vorentwurfsprozess in dieser Arbeit ist die Anwendung ...