Papers by Keyword: Maintenance

Abstract: Welding technologies are used to repair defects in cast parts of high - manganese austenitic steel (Hadfield steel). These include repair welding for newly manufactured castings, welding the formed defects in the old operating cast parts and, finally, for cladding layer of wear-resistant metal on the surface of the cast parts. Manual metal arc welding (MMAW) are used as often as gas metal arc welding (GMAW) and of flux-core wire welding (FCAW-S). These welding processes make possible to obtain a weld metal with the expected quality of the restored surface and a slight distortion of the base metal structure. The article presents methods of the casting repair by welding and surfacing. The parameters of welding and surfacing procedures are given, welding materials are recommended, and the methods for nondestructive testing of welds are prescribed.

Abstract: The construction industry is now facing expanding and extensive activities in the area of assessing and retrofitting buildings and bridges that aligns with the sustainable construction strategy. These activities recognise the importance of extending the life of existing construction works thereby delivering environmental, economic and socio-political benefits. Reinforced concrete structures and their reliability are currently receiving considerable attention as a significant part of these structures reaches the design service life. Degradation processes such as carbonation- and chloride-induced corrosion have a major influence on the reliability and serviceability of concrete structures. The submitted study is primarily focused on reinforced concrete structures whose main degradation factor is carbonation of the concrete cover. Examples of such structures are cooling towers or industrial chimneys. Structures in the power industry are usually designed for service life of 40 years. Carbonation-induced corrosion results in visible cracks and unacceptable spalling of concrete cover. The aim of the study is to improve predictions of carbonation-induced corrosion propagation and to critically compare the criteria for degradation level assessment used in practice. The probabilistic analysis is based on measurements of concrete cover and carbonation depths and continuous observations of signs of corrosion on structural surfaces. The example of an industrial chimney shows that the limit of a severe failure, which requires (possibly repeated) minor repairs, is exceeded after about 17 years. The critical failure limit (30% of structural surface with visible signs of corrosion) is reached after 50 years, which seems to be sufficient as it is after 10 years than the usual design service life.

Abstract: There is increasing awareness of life cycle costing (LCC) by the management who has lengthy experience in the operation and maintenance of the building. Maintenance of buildings includes a replacement, updating, and repair building components by predetermined standards. This paper aim at developing a prototype of building maintenance system for a campus in Yogyakarta. The prototype is referred to ISO 15686 as well as Regulation of Minister of Public Works. The system complements the service life of the building components that can be up dated regularly. The system accommodates the 25-years life cycle cost plan to assist campus management office. Research data obtained by Building Maintenance personals, the users of the building as well as previous studies for similar ones. From the results of life cycle costing, the study shows its detail life cycle cost plan.. Finally, a prototype for the operation and maintenance of the building is developed. Keywords: operation and maintenance, campus building, ISO 15686, life cycle costing

Abstract: Maintenance management is an orderly procedure to address the planning, organization, monitoring and evaluation of maintenance activities and associated costs. The maintenance management allows to have an efficient tool either to the management of the preventive or curative activity, an optimization of the production tool, and finally a follow-up of the costs and the performances. A good maintenance management system can help prevent problems and damages to the operating and storage environment, extend the life of assets, and reduce operating costs.In this paper, we will first present our model on the joint management of spare parts and maintenance. We will do a simulation study of our model, presented in the first section of this paper. The results of this study are presented in the second section through the presentation of the influence of certain parameters of the model on the operation of the system under consideration. This study carried out on the graphical interface of Matlab, which is one of the performance evaluation techniques. It allows to visualize the variations and anomalies which can be reached in the system considered as an overcoming of the repair of the machines by the unforeseen breakdowns.

Abstract: Since the quality management systems have undergone a significant change by taking into account the concept of risk, for the shipyards, becomes necessary, an approach aimed at improving organizational performance by implementing a actions plan based on the risks which may adversely affect the achievement of the objectives identification and assessment. The purpose of the paper is to propose a series of measures for improving the shiprepairs shipyards organizational performance,based on identifying and assessing the risks. The contents of the paper address the following aspects: summarizes the main changes made by the quality management systems; presents some developments in view of the identification and results of the risk assessment, identifying key performance indicators specific to the ships maintenance works in shiprepairs shipyards, the use of the performance indicators related to the management systems processes (quality, environment, security and occupational health). Concluding, the authors bring some proposals on improving the quality of institutional relations of the shiprepair shipyards.

Abstract: A mathematical model, statistically based on the theory of regression and correlation, could provide a viable solution to satisfy the need to predict the time required for the ship maintenance works in dock and / or berth in the shiprepairs shipyards, as part of the ships maintenance program required by the classification societies.

Abstract: In this paper we are studying the effects of temperatures ranging from-10 to 70°C of behavior on chlorinated PVC (CPVC), whose direct consequences are the strong modifications of the mechanical and physical characteristics of this polymer [1]. The purpose of this paper is to predict the damage of non-weld CPVC, based on simple tensile tests on non weld specimens. Thereafter and with the establishment of the relation Damage-Reliability, the critical life fraction βc is identified that predicts the time at which the damage becomes sudden and it is necessary to calculate the reliability and predictive maintenance of the system.

Abstract: The current level of the development of composite materials allows producing laminate structures with the desired properties. The application of supercomputer calculation and software systems, numerical modeling methods using finite elements enables the design and analysis of such structures. This article deals with design and calculation methods; the results of the full-scale tests of the joints of glued laminated timber with carbon fiber dowel pins and plates are presented. An overview of the behavior of such structures in corrosive environment and the comparative analysis with traditional steel components are also presented herein. Advantages and disadvantages of glulam joints where composite materials are used are noted. Examples of the joint use of composi\te materials and timber in Russia and internationally are given. Conclusions about the possibilities and ways of using composite materials in the design of wide-spanned glued timber structures are drawn.

Abstract: Maintenance is a system-specific activity that the purpose of which is to maintain or to increase time, performance and quality of machines and equipment use. The demand for technological equipment is still rising, resulting in often complicated and lengthy repairs. It is necessary to analyze the tools used in the construction of assembly joints and to describe the deficiencies that may occur during assembly. When contacting a material tool using a particular technology and assembly, it is necessary to analyze the impact on the final surface quality of the material.

Abstract: Plastics are the world's most widely used materials, largely due to their wide-spectrum use and relatively cheap manufacturing of complex shapes. Due to its properties, the use of plastics is possible in all manufacturing sectors. Important aspect of plastic moulding is that the heat passed to granulate is sufficient to properly heat up the plastic mixture. Another important factor is that the plastic mixture is blended as evenly as possible. Heterogeneities could lead to the formation of non-conformances with incorrect colour shades, unevenness of the mass or others. One of the factors that greatly affects the homogeneity of the mixture is the surface treatment of the guides that are designed to transport the granulate and it is important to take care of those lines.