Publicação: Análise de tomografias de cavidades observadas sob a decompressão de elastômeros expostos a hidrogênio
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CNPQ::ENGENHARIAS::ENGENHARIA AEROESPACIAL::MATERIAIS E PROCESSOS PARA ENGENHARIA AERONAUTICA E AEROESPACIAL
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At the department of Damage and Durability of Pprime Institute, the team has been interested in the formation of cavities in rubber materials exposed to hydrogen under high pressures followed by decompression. The phenomena was observed for the first time in 1990 and has not been widely investigated so far. In the last years, the usability of rubbers in industry has increased regarding its unique properties and benefits of efficiency and cost. In this context, connected to the world’s pressure of reducing emissions of greenhouse gases and clean sources of energy usage, we have the perfect environment. It is the opportunity to make this study of cavities one of the heads to encourage transportation moved by hydrogen, showing that we are close to have enough technology to improve the hydrogen volume energy efficiency within a reduced cost.
In this sense, the Pprime institute has recently developed an experience of in-situ monitoring of decompression with tomographies which provides access for the first time to a time-resolved 3D visualization of the field damage. In this way, it was possible to obtain a quantification over time of parameters such as number of cavities, size distribution, their relative distances and their form factor. This experiment, so far carried out on X-ray source of the laboratory, was recently brought to a synchrotron environment in order to gain in space and time resolution. In this sense, the objective of this internship was to contribute to the analysis of tomographies images acquired during the recently conducted test campaign on the Anatomix beamline of the Synchrotron SOLEIL.
During this study, it was possible to observe a lot of new phenomena never noticed before. In this situation, it was necessary to stipulate specific objectives taking into account the duration of the internship. They were: understanding better the formation of cavities with the new resolution in time and space resultant of the Synchrotron SOLEIL, elucidating the mechanisms at a very early stage; capturing new effects such as sphericity, volume of the sample, distance between cavities and the free surface, and distance between cavity-cavity. Furthermore, it was possible to work with more severe conditions of decompression to obtain more cavities into the experiment to improve the statistical analysis. Lastly, the influence of the crosslink density with the formation of cavities was analyzed.
The work was carried out on the ImageJ software, on the basis of already existing processing programs that were adapted, particularly to deal with a large number of data. The first step was to specify the mechanisms already demonstrated in an EPDM (Ethylene Propylene Diene Monomer) and to raise some questions about the early stages of growth.
Abstract
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Rapid gas decompression, Hydrogen, Elastomers, Fracture of elastomers
Citação
FONSECA, Fabio Machado Alves da. Analysis of tomographies of cavities observed under decompression of elastomers exposed to hydrogen. 2020. 43 f. Trabalho de Conclusão de Curso (Graduação em Engenharia Aeronáutica) – Universidade Federal de Uberlândia, Uberlândia, Uberlândia, 2022.