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The cause and type of solid particle erosion varies across different industries and locations in plants, for instance the particles could be volcanic ash in aero-engines, fly ash in boilers, exfoliated scale in steam turbines or mineral matter in oil excavation. In all cases the durability of materials can be improved through better surface engineering and coatings, but the development of these is restricted also due to lack of generic models. In this respect, the simulation of a single impact with finite element methods using 100.000 knots would take about 15 minutes. In order to simulate an entire particle erosion experiment, up to one billion of such impacts would have to be considered. In order to simulate an entire particle erosion experiment, the current work presents an alternative approach capable of calculating about half a billion impacts on a substrate in less than six hours on a standard PC. The predictions of the simulation will be compared to a steel sample at 600°C eroded by aluminum oxide particles with a velocity around 210 m/s.
The cause and type of solid particle erosion varies across different industries and locations in plants, for instance the particles could be volcanic ash in aero-engines, fly ash in boilers, exfoliated scale in steam turbines or mineral matter in oil excavation. In all cases the durability of materials can be improved through better surface engineering and coatings, but the development of these is restricted also due to lack of generic models. In this respect, the simulation of a single impact with finite element methods using 100.000 knots would take about 15 minutes. In order to simulate an entire particle erosion experiment, up to one billion of such impacts would have to be considered. In order to simulate an entire particle erosion experiment, the current work presents an alternative approach capable of calculating about half a billion impacts on a substrate in less than six hours on a standard PC. The predictions of the simulation will be compared to a steel sample at 600°C eroded by aluminum oxide particles with a velocity around 210 m/s.
Industrial radiography or Radiographic Testing (RT) is a method of non-destructive testing where many types of manufactured components can be examined to verify the internal structure and integrity of the specimen. The computer program aRTist can generate synthetic radiographs from a virtual RT test set-up. In the field of industrial radiology simulation is used, e.g. to optimize techniques for complex applications, to support the preparation of written procedures, and for education purposes.
The simulator aRTist combines analytical and Monte Carlo methods to efficiently model the radiation transport. The program comes with a graphical user interface written in Tcl/Tk. In combination of Tcl/Tk and the 3D capabilities of the visualization toolkit (VTK) a practical and convenient simulator has been realized. This will be illustrated by discussing application scenarios of classical radiography, X-ray computer tomography, and X-ray backscatter imaging. Additionally, some insight to the software implementation of the simulator will be given.
MaUS is an acronym for ”Material und Umweltsimulationen“. Plastics are in the focus of environmental politics due to their long term behaviour and therefore to their persistence. Not only that they appear as visible contaminants in the sea and on the beach, but their unknown behaviour concerning their additives as well as the related transformation products are anxious. Therefore, we wish to establish a certified reference method to provide a method for testing plastics.
Aim of this project is the development of fast motion standard reference methods for testing plastics regarding to their environmental compatibility. To establish these testing methods, we use polystyrene (PS) and polypropylene (PP) with environmental relevant brominated flame retardants, known for their persistent bioaccumulative and toxic (PBT) properties. In case of PS the material contains 1 wt% of 1,2,5,6,9,10-hexabromocyclododecan (HBCD) and in case of PP 0.1 wt% bromodiphenylether (BDE-209), which is known as a substance of very high concern (SVHC). Furthermore, we use polycarbonate (PC), which is still used as material in baby flasks and releases Bisphenol A (BPA), an estrogenic active substance.
As an additional material PTFE is used for its importance as a source for two ubiquitous environmental substances (PFOS and PFOA), whose toxicological effects are still incompletely known.
The focus in this current work is set on the transfer of potential pollutants out of applied materials mentioned above into environmental compartments like water or soil. Here an accelerated aging concept should be developed to shortened time consuming natural processes. For these resulting simulations we use a programmable weathering chamber with dry and wet periods and with high and low temperatures. These programmes run for several weeks and according to a defined sampling schedule we take water samples, run a clean-up procedure by SPE (Molecular imprinted polymers (MiPs) resp. polymer based cartridges (Waters Oasis HLB)) and analyse them by HPLC-UV resp. LC-MS/MS. Of most interest in case of flame retardants are photocatalytic transformation products. Therefore, we conduct a non-target-screening resp. a suspected target-screening by LC-MS/MS and HRMS.
The aim of this research is to characterize a surface that has experienced low wear on asperities. The procedure used is similar to an Abbott-Firestone approach and based on functional bearing of projected area, surface area and material volume. Surface features extracted from surface height maps provide more comprehensive information about topography changes due to wear. Thus, they were used to detect low wear volumes on the top of asperities.
The aim of this research is to characterize a surface that has experienced low wear on asperities. The procedure used is similar to an Abbott-Firestone approach and based on functional bearing of projected area, surface area and material volume. Surface features extracted from surface height maps provide more comprehensive information about topography changes due to wear. Thus, they were used to detect low wear volumes on the top of asperities.
To simulate a full fire engulfment during transportation or storage a closed removable head steel drum filled with 200 l Di-tert-butyl peroxide (DTBP) is subjected to a wood fire. Due to the enormous heat flux and the exothermic self-decomposition large flames arise and finally multiple fireballs occur. The fireballs consume up to 20 % of the total mass (20 % equals to 31 kg). They are characterized by high surface emissive power and large flames associated with high thermal radiation causing spontaneous ignition of objects in the surrounding. The measured sizes of the DTBP fireballs are smaller compared to the results of the general equations for hydrocarbon fireballs. Because these equations are recommended by the Health and Safety Executive (UK) to be applicable for organic peroxides explicit comparisons of DTBP with LPG, diesel and gasoline concerning the characteristics of fireballs are carried out. Also the burning time is compared and confirms a faster combustion of the peroxide. Moreover, the development of size and emissive power for DTBP and diesel fireballs are compared in a normalized graph. The results provide the assumption that new empirical models are required to be developed for hazard assessment of organic peroxide fireballs.
To simulate a full fire engulfment during transportation or storage a closed removable head steel drum filled with 200 l Di-tert-butyl peroxide (DTBP) is subjected to a wood fire. Due to the enormous heat flux and the exothermic self-decomposition large flames arise and finally multiple fireballs occur. The fireballs consume up to 20 % of the total mass (20 % equals to 31 kg). They are characterized by high surface emissive power and large flames associated with high thermal radiation causing spontaneous ignition of objects in the surrounding. The measured sizes of the DTBP fireballs are smaller compared to the results of the general equations for hydrocarbon fireballs. Because these equations are recommended by the Health and Safety Executive (UK) to be applicable for organic peroxides explicit comparisons of DTBP with LPG, diesel and gasoline concerning the characteristics of fireballs are carried out. Also the burning time is compared and confirms a faster combustion of the peroxide. Moreover, the development of size and emissive power for DTBP and diesel fireballs are compared in a normalized graph. The results provide the assumption that new empirical models are required to be developed for hazard assessment of organic peroxide fireballs.
Influence of impact angle and real target properties on drop test results of cubic containers
(2017)
Drop test scenarios with cubic containers without impact limiters at interim storage sites or in a final repository have been investigated by numerical simulations. An ideally flat drop is impossible to conduct as a free fall of a container even under laboratory conditions. Dynamic stresses and strains inside the container structure are sensitive to the impact angle. Even very small impact angles cause remarkable changes in the experimental or numerical results when a flat bottom or wall of a container hits a flat target. For drop tests with transport packages the International Atomic Energy Agency (IAEA) regulations define an essentially unyielding target. In contrast, potential accident scenarios for storage containers are derived from site-specific safety analyses or acceptance criteria in Germany. Each interim storage site or repository has a yielding or so-called real target with individual structural and material properties. The real target acts as a kind of impact limiter. A more conservative container design is required if the impact limiting effect of the target is not considered.