Examinando por Materia "Preventive maintenance"
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Ítem Characterization of the corrosion products of one of the pedestrian paths of the bridge "punto Cero" in the city of Medellin, Colombia(IOP PUBLISHING LTD, 2019-01-01) Velásquez A.A.; Jaramillo Raquejo D.; Velásquez A.A.; Jaramillo Raquejo D.; Universidad EAFIT. Departamento de Ciencias; Electromagnetismo Aplicado (Gema)In this work, we present the structural and magnetic characterization of the rust products formed on one of the pedestrian paths of the bridge "Punto Cero" of the city of Medellin, Colombia. The rust products were obtained by scraping three zones of the surface of the pedestrian path, namely: a surface that faces the sky, a surface that faces the floor of the path and a surface with a crack, where a high corrosion state was observed. The rusts were characterized by X-ray Diffraction, Fourier Transform Infrared Spectroscopy, room temperature Mössbauer Spectroscopy and Vibrating Sample Magnetometry. The analyses made by these techniques show that the rust products formed on the surfaces facing the sky and floor are composed mainly by goethite, lepidocrocite and maghemite, in percentages of 74%, 24% and 2% respectively, while the rust taken from the more corroded substrate presented 55% of goethite, 28% of lepidocrocite and 17% maghemite. Mössbauer and X-ray measurements were highly consistent with the percentages of each phase found in all rusts. The results suggest that in addition to the type of steel and the atmospheric conditions which the structure is exposed, the specific location of some surfaces plays an important role in the type and percentage of phase formed on them, being higher the presence of spinel phase in the zones more prone to moisture accumulation. On the other hand, the formation of maghemite could be an indication of an important state of corrosion of some surfaces, which could serve as a guide to start preventive maintenance actions on the structure. © Published under licence by IOP Publishing Ltd.Ítem Estudio de factibilidad para emprendimiento de una empresa prestadora de servicios generales y mantenimiento para el sector inmobiliario(Universidad Eafit, 2018) Chaparro González, María Teresa; Giraldo Hernández, Gina María; Arango Mejía, Juan ManuelThis project aims to perform the feasibility study for a company that would provide comprehensive general services for real estate in the city of Medellin. Currently there are multiple ventures in the market that provide independent services of locative repairs, but it has not been found that integrally unifies and provides these services to real estate, in addition to offering a plan of preventive maintenance in order to minimize costs in repairs that can be avoided thanks to this kind of maintenance. This initiative born from the current need expressed by some real estate agencies that operate in the city of Medellín, where their service and customer loyalty has been affected by the delay in response times and quality solution to the cases of maintenance required by the companies. tenants of the properties managed by the real estate companies, as well as offering improvement plans and preventive maintenance to the owners of the properties. Through the analysis of cost modeling and classification of the types of needs provided by the real estate in question, the administrative, legal, technical, economic, financial and market feasibility study will be carried out.Ítem Maintenance policy optimisation for multi-component systems considering degradation of components and imperfect maintenance actions(Elsevier Ltd, 2018-10-01) Martinod R, R.M.; Bistorin, Oliver; Castaneda Heredia Leonel F.; Rezg, Nidhal; Universidad EAFIT. Departamento de Ingeniería Mecánica; Estudios en Mantenimiento (GEMI)This article proposes a stochastic optimisation model in order to reduce the long-term total maintenance cost of complex systems. The proposed work is based on the following approaches: (i) optimisation of a cost model for complex multi-component systems consisting of preventive and corrective maintenance using reliability analysis, which faces two different maintenance policies (periodic block-type and age-based) and (ii) a clustering method for maintenance actions to decrease the total maintenance cost of the complex system. This work evaluates each maintenance policy and measures the effects on imperfect maintenance actions. Finally, the proposed optimisation model is applied to a numerical example which focuses on passenger urban aerial ropeway transport systems, in which the current maintenance policy has been evaluated, considering the established by the international regulation of passenger aerial cable cars. © 2018 Elsevier LtdÍtem Systematic exploration of signal-based indicators for failure diagnosis in the context of cyber-physical systems(Zhejiang University, 2019-01-01) Ruiz-Arenas S.; Rusák Z.; Horváth I.; Mejí-Gutierrez R.; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)Malfunction or breakdown of certain mission critical systems (MCSs) may cause losses of life, damage the environments, and/or lead to high costs. Therefore, recognition of emerging failures and preventive maintenance are essential for reliable operation of MCSs. There is a practical approach for identifying and forecasting failures based on the indicators obtained from real life processes. We aim to develop means for performing active failure diagnosis and forecasting based on monitoring statistical changes of generic signal features in the specific operation modes of the system. In this paper, we present a new approach for identifying emerging failures based on their manifestations in system signals. Our approach benefits from the dynamic management of the system operation modes and from simultaneous processing and characterization of multiple heterogeneous signal sources. It improves the reliability of failure diagnosis and forecasting by investigating system performance in various operation modes, includes reasoning about failures and forming of failures using a failure indicator matrix which is composed of statistical deviation of signal characteristics between normal and failed operations, and implements a failure indicator concept that can be used as a plug and play failure diagnosis and failure forecasting feature of cyber-physical systems. We demonstrate that our method can automate failure diagnosis in the MCSs and lend the MCSs to the development of decision support systems for preventive maintenance. © 2019, Zhejiang University and Springer-Verlag GmbH Germany, part of Springer Nature.