Selection of optimal material and operating conditions in composite manufacturing. Part I: computational tool

2003 ◽  
Vol 43 (2) ◽  
pp. 169-173 ◽  
Author(s):  
S.Y. Yang ◽  
I.N. Tansel ◽  
C.V Kropas-Hughes

The choice of cost-effective method of anticorrosive protection of steel structures is an urgent and time consuming task, considering the significant number of protection ways, differing from each other in the complex of technological, physical, chemical and economic characteristics. To reduce the complexity of solving this problem, the author proposes a computational tool that can be considered as a subsystem of computer-aided design and used at the stage of variant and detailed design of steel structures. As a criterion of the effectiveness of the anti-corrosion protection method, the cost of the protective coating during the service life is accepted. The analysis of existing methods of steel protection against corrosion is performed, the possibility of their use for the protection of the most common steel structures is established, as well as the estimated period of effective operation of the coating. The developed computational tool makes it possible to choose the best method of protection of steel structures against corrosion, taking into account the operating conditions of the protected structure and the possibility of using a protective coating.


2014 ◽  
Vol 952 ◽  
pp. 20-24 ◽  
Author(s):  
Xue Jun Xie

The selection of an optimal material is an important aspect of design for mechanical, electrical, thermal, chemical or other application. Many factors (attributes) need to be considered in material selection process, and thus material selection problem is a multi-attribute decision making (MADM) problem. This paper proposes a new MADM method for material selection problem. G1 method does not need to test consistency of the judgment matrix. Thus it is better than AHP. In this paper, firstly, we use the G1 method to determine the attribute weight. Then TOPSIS method is used to calculate the closeness of the candidate materials with respect positive solution. A practical material selection case is used to demonstrate the effectiveness and feasibility of the proposed method.


Author(s):  
Л.Б. Леонтьев ◽  
Н.П. Шапкин ◽  
А.Л. Леонтьев ◽  
В.Н. Макаров ◽  
А.В. Арон

Повышение долговечности трибосопряжений судовых дизелей, определяющих их ресурс, представляет собой актуальнейшую проблему, обусловленную как безопасностью мореплавания, так и экономическими факторами. Основной причиной отказов коленчатых валов двигателей, определяющих необходимость капитального ремонта, является износ шеек. Решение проблемы повышения износостойкости и, соответственно, долговечности связано с применением трибоактивных присадок в смазку. Несмотря на глубокие и обстоятельные исследования в области применения органо-неорганических материалов для использования в качестве присадок в моторное масло для повышения долговечности трибоузлов осуществить выбор оптимального материала для конкретных условий практически невозможно, так как исследования выполнены для различных условий эксплуатации и по различным методикам. Цель работы – разработка триботехнической присадки к моторным маслам, обеспечивающей повышение надежности и эффективности технической эксплуатации судовыхсреднеоборотных дизелей путем формирования тонкопленочного металлокерамического покрытия на поверхностях трения стальных деталей трибоузлов, позволяющего получить оптимальный комплекс параметров материала износостойкого покрытия. В работе представлены исследования эксплуатационных свойств присадок в моторное масло 17 органо-неорганических триботехнических материалов 4 групп — природные и искусственные полимеры, из которых были изготовлены свыше 20 композиций и композитов. Установлено, что наиболее перспективным является использование нанокомпозитов на основе вермикулита, модифицированного кислотой, в качестве присадок в моторное масло, так как они обладают минимальными коэффициентом трения при граничной смазке (0,007–0,014) а также высокой износостойкостью стали 40Х и обеспечивают минимальную величину скорости изнашивания вкладыша подшипника, благодаря чему повышается ресурс трибосопряжения более, чем в 3 раза, и соответственно снижаются эксплуатационные расходы. Increasing the durability of the tribo-couplings of marine diesel engines, which determine their resource, is an urgent problem due to both the safety of navigation and economic factors. The main reason for engine crankshafts failures, which determine the need for major repairs, is the wear of the necks. The solution to the problem of increasing wear resistance and, accordingly, durability is associated with the use of triboactive additives in the lubricant. Despite in-depth and thorough research in the field of application of organo-inorganic materials for use as additives in engine oil to increase the durability of tribo-nodes, it is almost impossible to choose the optimal material for specific conditions, since the studies were carried out for various operating conditions and according to various methods. The purpose of the work is to develop a tribotechnical additive to motor oils that provides an increase in the reliability and efficiency of technical operation of medium-speed marine diesel engines by forming a thin-film metal-ceramic coating on the friction surfaces of steel parts of tribo-nodes, which allows to obtain an optimal set of parameters of the wear-resistant coating material. The paper presents studies of the operational properties of additives in engine oil of 17 organo-inorganic tribotechnical materials of 4 groups — natural and artificial polymers, from which more than 20 compositions and composites were made. It has been established that the most promising is the use of nanocomposites based on vermiculite modified with acid as additives in engine oil, since they have a minimum coefficient of friction with boundary lubrication (0.007-0.014) as well as high wear resistance of 40X steel and provide a minimum wear rate of the bearing liner, thereby increasing the tribo-tension life by more than 3 times, and, accordingly, operating costs are reduced.


Author(s):  
Jude Iyinbor

The optimisation of engine performance by predictive means can help save cost and reduce environmental pollution. This can be achieved by developing a performance model which depicts the operating conditions of a given engine. Such models can also be used for diagnostic and prognostic purposes. Creating such models requires a method that can cope with the lack of component parameters and some important measurement data. This kind of method is said to be adaptive since it predicts unknown component parameters that match available target measurement data. In this paper an industrial aeroderivative gas turbine has been modelled at design and off-design points using an adaptation approach. At design point, a sensitivity analysis has been used to evaluate the relationships between the available target performance parameters and the unknown component parameters. This ensured the proper selection of parameters for the adaptation process which led to a minimisation of the adaptation error and a comprehensive prediction of the unknown component and available target parameters. At off-design point, the adaptation process predicted component map scaling factors necessary to match available off-design point performance data.


Author(s):  
Adam Kozakiewicz ◽  
Stanislaw Jóźwiak ◽  
Przemysław Jóźwiak ◽  
Stanisław Kachel

The structural and strength analysis of the material used to construct such an important engine element as the turbine is of great significance, both at the design stage as well as during tests and expertises related to emergency situations. Bearing in mind the conditions above mentioned, the paper presents the results of research on the chemical composition, morphology and phased structure of the metallic construction material used to produce the blades of the high and low pressure turbine of the RD-33 jet engine, which is the propulsion unit of the MiG-29 aircraft. The data obtained as a result of the material tests of the blades allowed, on the basis of the analysis of chemical composition and phased structure, to determine the grade of the alloy used to construct the tested elements of the jet engine turbine. The structural stability of the material was found to be lower in comparison with engine operating conditions, which manifested itself as a clear decrease in the resistance properties of the blade material. The results obtained can be used as a basis for analyzing the life span of an object or a selection of material replacements, which enable to produce the analyzed engine element.


2019 ◽  
Vol 22 (2) ◽  
pp. 159-172
Author(s):  
Arkadiusz Mroczek

The fast growth of the service sector is one of the characteristic features of the contemporary economy. Amongst other CEE countries, Poland is one of the emerging locations for this sector. The aim of the paper is to examine and compare the business service sector in India, Ireland and Poland. Both India and Ireland are exceptional locations for this industry, so comparing the state and operating conditions in Poland with those countries can be insightful. A literature study is used to determine the motives of companies undertaking offshore investments, upon which a selection of location factors is made. In the empirical part, those factors are analyzed in a descriptive way. This allows us to draw conclusions concerning this sector in Poland. This country, to some extent, possesses selected positive features of both India and Ireland, which explains the current growth of the sector.


2021 ◽  
pp. 172-181
Author(s):  
Oksana Y. Vasileva ◽  
Marina V. Nikulina Nikulina ◽  
Juri I. Platov Platov

The article deals with the problem of selecting efficient ships by the feasibility study in which brake power, main dimensions, payload, speed and fuel consumption are determined. The necessity of using the proposed selection at the initial stage of the ship's design is justified; the problems that arise at the present time are denoted. The purpose of the article is to propose a criterion for the selection of efficient vessels, "tied" to the operating conditions, based on the marginal cost of the ship. A method for its determination is presented. At the same time, annual revenues and operating costs should be determined by modern methods of business planning for the operation of the fleet. When searching for the parameters of the ship, the optimal fuel consumption is determined. The rest of the costs can be found according to the coefficients "tied" to the fuel consumption and calculated on the basis of existing prototypes. The results of calculations by the proposed method are shown; its merits and opportunities for improvement are noted with the availability of relevant information. The conclusion is made about the convenience and applicability of the proposed option for selecting efficient ship for the feasibility study based on optimization methods for determining the parameters of vessels under conditions of a high level of use of information technologies.


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