The Role of Self-Assembly in Additive Manufacturing of Aerospace Applications

Additive manufacturing is a strategy to produce parts with complex geometries whose process is prohibitive in cost or impossible through subtractive or formative techniques. Research groups are optimizing additive manufacturing processes to improve their performance and reduce the cost of aerospace parts. One of the emerging design techniques is self-assembly which seeks to reduce the number of parts to produce best design practices and rules. Self-assembly represents a comprehensive strategy that improves process time, product quality, cost of materials, and printability. The purpose of this chapter is to review the technological contributions that self-assembly has had in the additive manufacturing of aerospace parts. Future perspectives of the role of self-assembly in additive manufacturing are proposed. According to what was found in this research, self-assembly will facilitate the additive manufacturing of parts in various technological sectors where the manufacture of lightweight parts with high added value and restrictive regulations are required.

Development of Technological Solutions for Sewer Rehabilitation Using Clinker Brick

The aim of the work is to develop a technology for the restoration of damaged sections of sewer collectors using clinker bricks. A significant part of such collectors in the Ukraine has completely exhausted their depreciation resource. For their construction, concrete and reinforced concrete were used, which are subject to destruction as a result of the influence of many factors and, above all, microbiological corrosion. Therefore, the selection of the optimal repair technology using corrosion-resistant clinker brick is relevant. The paper considers the problems of repair and reconstruction of worn-out collectors. Technical and technological solutions of an open method for their recovery using pneumatic formwork and corrosionresistant clinker brick are presented. The design of the collector lining structure has been carried out using the finite element method. To justify the feasibility of using the proposed technology, two options for restoring a worn-out collector have been considered: the “pipe-in-pipe” method and method developed by the authors using clinker bricks. The second option in terms of the cost of materials is almost four times more economical and more expedient than the first one (where polymer materials are used). The advantage of restoring circular sewer collectors by means of laying clinker bricks lies in the durability and resistance of this material (taking into account the anticorrosive composition of concrete) to the aggressive effects of the sewer environment. It should be noted that the application of the developed restoration technology is the most appropriate in conditions of sparse building or outside the city due to the significant volume of earthworks.

Thermomechanical voltages in the insulation of traction electric machines of locomotive

In recent years, the production of locomotives in our country has increased significantly. At the same time, a lot of efforts are made to increase the power, reliability and efficiency of their work. One of the key components of any locomotive is electric traction machines, which are usually designed to the limit in order to obtain maximum torque and power density in the limited space of the rolling stock. Previously, this problem was solved by increasing the electromagnetic properties of materials, thermal conductivity of insulating materials. However, this path has exhausted the possibilities for increasing the efficiency of traction electric machines. As the design of traction electric machines improves, their level of functionality, reliability and durability increases, electric traction systems become more relevant and important for reducing the cost of materials, maintenance and ensuring traffic safety. The insulation state of the windings of traction electric machines mainly determines their reliability and performance, affects the service life and the cost of maintenance. Therefore, when designing a traction electric machine, it is important to take into account all operational factors that determine the optimal service life of a locomotive. The article discusses the effect of thermomechanical stresses in the insulation of traction electric machines on their reliability and durability.

Selection of a heating system based on climatic conditions of Uzbekistan and on calculations of the technical and economic indicators of alternative systems: A case study of the solar greenhouse with a transformable building

This paper presents studies on the choice of a heating system based on calculations of economic efficiency and payback periods for alternative systems, a solar greenhouse with a transformable body. The purpose of the work is to carry out calculations to determine the consumption of fuel resources necessary to ensure the required amount of energy for the heating season: consumption of natural gas, solid fuel (coal) and electricity for heating a greenhouse with a transformable (adjustable) body. Analytical methods were used to determine the cost of materials and the main units of a greenhouse with a transformable (adjustable) body. Depending on the shape of the greenhouse, the total costs, economic efficiency and payback periods are determined. The research work carried out shows that, in terms of the cost of construction and consumption of materials, the developed greenhouse with transformable (adjustable) body are quite acceptable for its successful use among farmers and private households in the Republic of Uzbekistan. Calculation of economic efficiency and payback periods for greenhouses with a transformable housing allows you to choose the most acceptable heating system and technical characteristics of alternative systems acceptable for the climatic conditions of Uzbekistan.

Feasibility evaluation of using additive technologies in aerospace products

The paper studies the feasibility of using additive technologies in the manufacture of parts of complex shapes for aerospace products. The results of the structural analysis of a part helped find the directions of topological optimization and optimize the part’s design. To confirm the relevance of the design optimization, we carried out static and dynamic strength calculations in the Siemens NX software package. The paper considers technologies for manufacturing the part by 3D metal printing and traditional milling on a numerically controlled machine. In order to obtain initial data for economic calculations, we simulated manufacturing processes in various software systems. To study the feasibility of metal printing technology, we carried out its technical and economic analysis, and found that the production program, technological processing modes and the cost of materials affect the cost of the product.

Application of Multi-Criteria Decision-Making Methods in Sustainable Manufacturing Management: A Systematic Literature Review and Analysis of the Prospects

Due to increasing environmental regulation and customers’ demand for environmentally friendly products, organizations have been required to adopt sustainable manufacturing practices by implementing clean technology (Cleantec) to manufacture green products. By adopting environmental practices, organizations can also achieve qualitative and quantitative benefits that help them remain competitive in the market while meeting governmental environmental policies, such as lowering energy and the cost of materials. The significant number of articles addressing sustainability in manufacturing published in the past few years attests to the importance of the topic. However, not many studies have been developed to understand the decision-making process in sustainable manufacturing. Therefore, the objective of this paper is to conduct a systematic literature review on the application of multi-attribute decision-making (MADM) methods in sustainable manufacturing. A total of 158 papers, published between 2009 and 2018, met the criteria set in the research methodology. The 158 papers were then analyzed and classified into seven categories: (i) SM domain, (ii) activity within the organization, (iii) decision goals, (iv) decision-makers involved (group or individual), (v) uncertain data, (vi) SM aspects (social, environmental, and economic), and (vii) MADM methods. Among the results, we identified that AHP is the most applied MADM method and, regarding the activities of the organization, MADM methods have been the most frequently applied to strategy management and supply chain. We also identified a tendency to consider uncertain and imprecise data in the decision-making process. Another result is that all the three domains — economic, environmental and social — were considered in most of the papers, followed by the combination of the economic and environmental perspectives. In the conclusion, some recent trends and future research directions are highlighted.

Automated Low-Cost LED-Based Sun Photometer for City Scale Distributed Measurements

We propose a monochromatic low-cost automatic sun photometer (LoCo-ASP) to perform distributed aerosol optical depth (AOD) measurements at the city scale. This kind of network could fill the gap between current automatic ground instruments—with good temporal resolution and accuracy, but few devices per city and satellite products—with global coverage, but lower temporal resolution and accuracy-. As a first approach, we consider a single equivalent wavelength around 408 nm. The cost of materials for the instrument is around 220 dollars. Moreover, we propose a calibration transfer for a pattern instrument, and estimate the uncertainties for several units and due to the internal differences and the calibration process. We achieve a max MAE of 0.026 for 38 sensors at 408 nm compared with AERONET Cimel; a mean standard deviation of 0.0062 among our entire sensor for measurement and a calibration uncertainty of 0.01. Finally, we perform city-scale measurements to show the dynamics of AOD. Our instrument can measure unsupervised, with an expected error for AOD between 0.02 and 0.03.

Durability of potholes filled with waste materials

Repairing and maintenance of potholes continues to be a serious problem for road construction organizations as they need to be reconstructed time to time. For rural and suburb areas the maintenance of potholes is rarely done because of high cost of materials and availability of equipment. Here is when the idea of using waste materials in potholes patching is bolded. With rapid increase of population and construction industry the disposal of waste material seems to be a major challenge for country like Afghanistan where large amount of plastic is being disposed to environment which due to non-biodegradable properties of plastic it would stay in environment almost forever and will cause pollution. Hence, the utilization of waste plastic is a big need for countries. Simultaneously, with spreading cities and upgrading roads lack of origin materials may occur on the other hand waste demolished materials from destructed buildings are being disposed on country sides and often in cities which create land pollution and traffic congestion. However, they can be used in road construction as a replacement of natural aggregate and fillers. Which will reduce in cost of the projects and help in reduction of these materials form environment. In this research poly ethylene plastics (PE) were used as admixture of bitumen in 4%, 6%,8% and 10% which came out that 8% is best for the mix. Accordingly waste demolished aggregate was used as a fully replacement of original aggregate. Basic aggregate tests were done on demolished aggregate and it was found that it can be used in bitumen mixes for use in district roads and village roads.

DESIGNING STRUCTURES OF RIGID ROAD CLOTHING WITH THE APPLICATION OF METALLURGICAL BY-PRODUCTS INDUSTRY FOR DISTRIBUTION R OADS OF REGIONAL SIGNIFICANCE

Постановка задачи. Разработать рецептуры шлаковых асфальтобетонных смесей с оптимальным содержанием битума, исследовать их физико-механические свойства и на основании полученных результатов выявить преимущества и обосновать комплексное применение отходов металлургической промышленности на стадии проектирования конструкций дорожных одежд. Результаты. Проведены испытания образцов материалов конструктивных слоев в лабораторных условиях, дана оценка физико-механическим и прочностным характеристикам на основе определения фактического модуля упругости путем послойного измерения прогибов дорожной одежды на экспериментальном участке. Выводы. Полученные результаты исследований свидетельствуют о возможности применения шлаковых материалов в составе различных слоев нежесткой дорожной одежды на стадии проектирования конструкции. Выявлены преимущества использования шлаковых материалов в процессе строительства автомобильных дорог за счет сокращения затрат на материалы и в процессе эксплуатации с позиции безопасности и экологичности. Problem statement. To develop formulations of slag asphalt concrete mixtures with an optimal bitumen content, to study their physical and mechanical properties, and, on the basis of the results obtained, to identify the advantages and substantiate the integrated use of metallurgical industry waste at the stage of designing pavement structures. Results. The tests of samples of materials of structural layers in laboratory conditions were carried out, an assessment of the physical-mechanical and strength characteristics was given based on the determination of the actual modulus of elasticity by layer-by-layer measurement of the deflections of the pavement in the experimental section. Conclusions. The obtained research results indicate the possibility of using slag materials in the composition of various layers of non-rigid pavement at the design stage of the structure. The advantages of using slag materials in the process of building highways by reducing the cost of materials and in the process of operation from the standpoint of safety and environmental friendliness are revealed.

Performance of Light Weight Concrete with Coconut Shell and Fly Ash

The major factor that affects the housing delivery is high cost of materials for any conventional concrete. This has lead to find an alternative. An attempt has been made to find an alternative by using partial replacement of coarse aggregate by coconut shell aggregate and cement by fly ash. This report provides the information obtained from a literature search. And also provides laboratory experiments on Cement, Sand, Coarse aggregate and Coconut shell. This project is done using partial replacement of coarse aggregate by coconut shell aggregate and cement by fly ash.10 % of fly ash was kept constant as replacement for cement. And Coarse aggregate was replaced by 5%, 10%, 15%, and 20% of coconut shell aggregate.30 concrete cubes of 150x150x150 mm size were casted and 3 cubes were tested after 7 days of curing and 3 cubes were tested after 28 days of curing for each percentage.30 concrete Cylinders of 150x300 mm size were casted and 3 Cylinders were tested after 7 days of curing and 3 Cylinders were tested after 28 days of curing for each percentage.15 concrete Beams of 100X100X500 mm size were casted and 3 beams were tested after 28 days of curing for each percentage. Two models were done using ANSYS Software using the same failure loads from the experimental part. Keywords: Light weight concrete, coconut shell, Fly-ash, experimental.