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Aufsatz
Crack Paths at Multiple-crack Systems in Anisotropic Simulation and Experiment
(2014-06-27)
This paper is targeted on numerical methods for accurate crack tip loading analysis and crack path prediction. Those are based on finite element calculations of the boundary value problem. Applying path-independent integrals to curved cracks in order to accurately calculate the J-integral, energy release rate (ERR) or stress intensity factors (SIF) is still not state of the art. Contours which are not confined to the crack tip require special analytical preparation and numerical treatment to supply results which are ...
Konferenzveröffentlichung
Verbesserung der Produktqualität durch eine frühe Anforderungsvalidierung mithilfe der virtuellen Realität
(Otto-von-Guericke-Universität, Fakultät für Maschinenbau, 2015)
If features meet customer requirements to 100%, one speaks about quality. In the context of the requirement identification various methods are used to generate the conscious customer requirements. Hidden (unconscious) customer requirements are not taken into account. From collected customer requirements, however, the later features can be derived. Therefore, in the developed product it often comes to a deviation from the characteristics required by the customer. Any deviation results in a lower product quality. The ...
Aufsatz
Relaxation properties of polyoxymethylene and ethylene–octene copolymer blend in solid and melt states
(2012-08-30)
Rheological properties of polyoxymethylene (POM) and ethylene–octene copolymer (EOC) in solid and melt states were investigated. Blends were prepared with a twin screw extruder at broad component wt-to-wt ratios (10, 30, 50, 70, 90 wt% of EOC). The morphology as well as calorimetric, rheological, and elastic properties of the blends were studied. The investigation showed that POM/EOC blends were heterogeneous in nature and had a broad phase transition region between 30 and 70 wt% of POM. Because during processing ...
Aufsatz
Predictive Simulation-based Optimisation of Cooling System Including a Sprinkler Tank
(2018)
Prerequisite for an efficient cooling energy system is the knowledge and the optimal combination of different operating conditions of individual compression and free cooling chillers. The performance of cooling systems depends on its part load performance and its condensing temperature, which are often unknown. Recorded energy data remains unused and manufacturers' data significantly differs from the real performance. For this purpose, manufacturer and real data are combined and continuously adapted to form partial ...
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
Process and utility systems integration and optimisation for ultra-low energy milk powder production
(2017-04-26)
This study applies a Total Site Heat Integration approach in conjunction with a detailed process and utility model, to develop an innovative ultra-low energy milk powder plant design. The basis for the analysis is a state-of-the-art modern milk powder plant that requires 5265 MJ/tp of fuel and 210.5 kWh/tp (58.5 MJe/tp) of electricity. The model of the modern milk powder plant was validated against industrial data and changes to process and/or utility systems are targeted and implemented into the model to understand ...
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
Numerical Two-Scale Simulations of Damage Evolution at Refractory Materials
(2014-02-25)
Fracture and damage processes on micro- and mesoscale are combined with macroscale simulations applying numerical multiscale approaches. Cracks and grain boundaries are reproduced in cell models that take account of transand intercrystalline crack growth. The global, in general thermomechanical boundary value problem is considered within a continuum mechanics framework. Two approaches are presented combining the scales. Simple processes on the smaller level are described in analytical models including the damage ...