Testing of Thin-Walled Tubular Workpieces

In accordance with the Russian Federation State program called “Industrial growth and improving competitiveness” it becomes more wide-spread to use thin-walled makes for pieces, modern materials with new treating methods in mechanical engineering, in automobile production and modern aviation industry. As well as requirements for quality and mechanical characteristics of finished products constantly grow. In relation to these standards, methods of intensive irreversible deformation under conditions of complex stressed state are used with increasing frequency. Study of the following parameters has a great practical importance: loaded capability of the makes during exploitation and work material strength performance under complex production process. Such strain tasks are frequently counted as most complex and demand experimental verification because of geometric and physical task nonlinearity.The current study proposes testing method for thin-walled tubular workpieces which combines implementation simplicity with a wide range of strain-stressed state charts.

Download Full-text

Creep of isotropic homogeneous and nonaging of linear-viscoelastic materials under the complex stress state

Bulletin of Taras Shevchenko National University of Kyiv. Series: Physics and Mathematics ◽

10.17721/1812-5409.2019/1.34 ◽

2019 ◽

pp. 150-153

Author(s):

Y. V. Pavlyuk

Keyword(s):

Stress State ◽

Stressed State ◽

Complex Stress ◽

Complex Stress State ◽

Complex Stressed State ◽

Viscoelastic Materials ◽

Linear Viscoelastic ◽

Thin Walled ◽

Hereditary Properties ◽

Axial Stretching

The relaxation of isotropic homogeneous and non-aging linear-viscoelastic materials under conditions of complex stress state is considered. Thin-walled tubular specimens of High Density Polyethylene (HDPE) for creep under a single-axial stretching, with a pure twist and combined load tension and torsion are considered as base experiments, tests. The solution is obtained by generalizing the initial one-dimensional viscoelasticity model to a complex stressed state, constructed using the hypothesis of the proportionality of deviators. The heredity kernels are given by the Rabotnov’s fractional-exponential function. The dependence between the kernels of intensity and volumetric creep is established, which determine the scalar properties of linear viscoelastic materials in the conditions of a complex stressed state in the defining equations of the type of equations of small elastic-plastic deformations, and the kernels of longitudinal and transverse creep defining the hereditary properties of linear-viscoelastic materials under the conditions of the uniaxial tension. The problems of stress relaxation calculation of thin walled tubes under combined tension with torsion have been solved and experimentally approved.

Download Full-text

Energy absorbed ability and damage analysis for honeycomb sandwich material of bio-inspired micro aerial vehicle under low velocity impact

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406220975427 ◽

2020 ◽

pp. 095440622097542

Author(s):

Jianxun Du ◽

Peng Hao ◽

Mabao Liu ◽

Rui Xue ◽

Lin’an Li

Keyword(s):

Honeycomb Structure ◽

Low Velocity Impact ◽

Parameter Study ◽

Low Velocity ◽

Micro Aerial Vehicle ◽

Thin Walled Structures ◽

Wide Range ◽

Aerial Vehicle ◽

Thin Walled ◽

The Impact

Because of the advantages of light weight, small size, and good maneuverability, the bio-inspired micro aerial vehicle has a wide range of application prospects and development potential in military and civil areas, and has become one of the research hotspots in the future aviation field. The beetle’s elytra possess high strength and provide the protection of the abdomen while being functional to guarantee its flight performance. In this study, the internal microstructure of beetle’s elytra was observed by scanning electron microscope (SEM), and a variety of bionic thin-walled structures were proposed and modelled. The energy absorption characteristics and protective performance of different configurations of thin-walled structures with hollow columns under impact loading was analyzed by finite element method. The parameter study was carried out to show the influence of the velocity of impactor, the impact angle of the impactor and the wall thickness of honeycomb structure. This study provides an important inspiration for the design of the protective structure of the micro aerial vehicle.

Download Full-text

Legal aspects of the brand protection in Ukraine and world

Scientific and Informational Bulletin of Ivano-Frankivsk University of Law Named after King Danylo Halytskyi - Scientific and informational bulletin of Ivano-Frankivsk University of Law named after King Danylo Halytskyi ◽

10.33098/2078-6670.10.22.133-143 ◽

2020 ◽

pp. 133-143

Author(s):

Ivanna Babetska

Keyword(s):

Public Relations ◽

Practical Importance ◽

Legal Protection ◽

Legal Regulation ◽

Legal Aspects ◽

Scientific Article ◽

Protection Mechanism ◽

Brand Protection ◽

Wide Range ◽

International Regulations

Purpose. The purpose of the scientific article is to establish the ratio of the meanings of the concepts "trademark", "brand" and "well-known" trademark and then to characterize their common and distinctive features. Indicate the gaps in current legislation and the need to refine certain rules in this aspect to determine the aspects of protection and protection of the brand. Methodology. The methodology includes a comprehensive analysis and generalization of the available scientific and theoretical material and the formulation of appropriate conclusions and recommendations. During the research, the following methods of scientific knowledge were used: terminological, dialectical, logical-semantic, logical-normative, system-structural. Results: in the course of the conducted study, the main and optional components of the brand are determined, which make it possible to determine the features of its legal protection. It has been proved that despite a fairly wide range of domestic and international regulations, there are certain shortcomings of the brand protection mechanism. Originality. The study found that a trademark differs from a brand in that a trademark is a designation that is only the basis of the brand, as for the trademark are not essential such properties of the designation as a certain level of information among consumers and quality as a basis. gaining a reputation; the concept of "brand" is an evaluative, conditional concept, and therefore its consolidation at the regulatory level is impractical. It is sufficient to establish the factors on the basis of which the trademark can be considered "well known". A "well-known" trademark is a designation that is familiar to a wide range of consumers through its use to designate certain goods. Practical importance. The results of the study can be used in law-making activities for the purpose of legal regulation of public relations in the sphere of legal protection of the brand.

Download Full-text

The use of «coasorption» concept while describing the effect of coagulants on the wastewater aqua systems

Vodosnabzhenie i sanitarnaia tehnika ◽

10.35776/vst.2021.03.06 ◽

2021 ◽

pp. 33-39

Author(s):

Е.В. Алексеев

Keyword(s):

Wastewater Treatment ◽

Industrial Wastewater ◽

Practical Importance ◽

Quantitative Relationship ◽

Synthetic Dyes ◽

Pollutant Concentrations ◽

Wide Range ◽

Complex Chemical Composition ◽

The One ◽

Raw Wastewater

Широкое распространение реагентного коагулирования в технологии очистки природных и промышленных сточных вод обусловлено, с одной стороны, сложностью химического состава и фазово-дисперсного состояния их аквасистем, с другой – многофакторностью действия на них коагулянтов. Рассмотрены основные механизмы взаимодействия коагулянтов и загрязняющих веществ на примере очистки промышленных сточных вод, содержащих органические вещества (поверхностно-активные вещества и синтетические красители). Физико-химическое понятие «коагуляция» отражает только один из механизмов действия коагулянтов на загрязнители. Принятые в настоящее время технологические показатели «доза коагулянта» и «удельная доза коагулянта» также не отражают многообразие взаимодействий загрязняющих веществ с солями коагулянтов и не привязаны к результату коагулирования. Это обусловливает трудность описания совокупного действия физико-химических процессов при добавлении коагулянтов в очищаемые воды и его количественной оценки. Решение проблемы возможно введением понятия «коасорбция», определяющего многофакторность взаимодействия коагулянтов с загрязняющими веществами в процессах очистки сточных вод коагулированием, и технологического показателя «удельная коасорбция», устанавливающего количественную взаимосвязь между величинами загрязняющих веществ в исходной и очищенной воде с дозой коагулянта. Графически представлены функции удельной коасорбции в форме изотерм коасорбции для двух типов поверхностно-активных веществ и синтетических красителей. На основании результатов анализа особенностей изотерм показано, что они отражают разные механизмы взаимодействия коагулянтов и загрязняющих веществ. Использование коасорбции как технологического понятия способствует выявлению механизмов взаимодействия загрязняющих веществ с коагулянтом и созданию наилучших условий для осуществления процесса коагулирования. Функциональное описание изотерм коасорбции позволяет экстраполировать результаты пробного коагулирования в широком интервале концентраций загрязняющих веществ. Практическое значение изотерм удельной коасорбции состоит в возможности определения доз реагентов при коагулировании воды по начальному содержанию загрязняющих веществ и требуемому в очищенных водах. The widespread use of chemical coagulation in purification of natural water and industrial wastewater is due, on the one hand, to the complex chemical composition and phase-disperse state of their aqua systems, and on the other hand, to the multifactorial effect of coagulants on them. The main mechanisms of interaction between coagulants and pollutants are considered through the example of industrial wastewater treatment containing organic substances (surfactants and synthetic dyes). The physicochemical term «coagulation» reflects only one of the mechanisms of the effect of coagulants on pollutants. The currently accepted process parameters «dose of coagulant» and «specific dose of coagulant» do not reflect the variety of interactions of pollutants with coagulant salts either, and are not linked to the result of coagulation. This makes it difficult to describe the collective effect of physicochemical processes while adding coagulants to the treated water and to quantify it. The solution to the problem is possible introducing the concept of «coasorption» that determines the multifactorial origin of the interaction of coagulants and pollutants in the processes of wastewater treatment by coagulation; and the process parameter «specific coasorption» that establishes a quantitative relationship between the concentrations of pollutants in raw wastewater and effluent with a dose of coagulant. The specific coasorption functions are graphically presented in the form of coasorption isotherms for two types of surfactants and synthetic dyes. Based on the results of the analysis of the features of the isotherms, it is shown that they reflect different mechanisms of interaction between coagulants and pollutants. The use of coasorption as a technological concept provides for identifying the mechanisms of interaction of pollutants with a coagulant and establishing the best conditions for the coagulation process. The functional description of the coasorption isotherms allows extrapolating the results of trial coagulation in a wide range of pollutant concentrations. The practical importance of specific coasorption isotherms provides for determining the dosages of chemicals during coagulation of water based on the initial concentration of pollutants and effluent standard.

Download Full-text

Optimization of the design of the cooling duct of thin!walled heat-stressed structures

10.36652/0042-4633-2021-7-19-21 ◽

2021 ◽

pp. 19-21

Author(s):

Keyword(s):

Stressed State ◽

Ribbed Shell ◽

Thin Walled

The results of modeling of the stressed state of a thinwalled profiled ribbed shell of the cooling duct of heatstressed structures with additional hollow bridges made on the shell ribs with an increased surface for soldering are presented. It is shown that the implementation of the bridges makes it possible to reduce the stresses arising in the inner shell, or to increase the pressure of the cooler in the duct. Keywords: cooling duct, rib, milled inner shell, outer jacket [email protected]

Download Full-text

A Simple Analytical Theory for Interpreting Measured Total Pressure in Multiphase Flows

Journal of Fluids Engineering ◽

10.1115/1.2820659 ◽

1998 ◽

Vol 120 (2) ◽

pp. 385-389 ◽

Cited By ~ 5

Author(s):

Abhijit Guha

Keyword(s):

Total Pressure ◽

Multiphase Flows ◽

Practical Importance ◽

Present Theory ◽

Vapour Phase ◽

Solid Particles ◽

Analytical Theory ◽

Nonequilibrium Processes ◽

Measuring Device ◽

Wide Range

This paper presents a simple, analytical theory for determining total pressure in multiphase flows, a subject of theoretical interest as well as of practical importance. It is shown here that the nonequilibrium processes occurring in the vicinity of a measuring device have a significant influence on the magnitude of flow velocity inferred from Pitot measurements. The present theory predicts that, depending on the size of the particles or droplets, the total pressure varies monotonically between the two limiting values: the frozen total pressure (when there is no interphase mass, momentum, and energy transfer in the decelerating flow toward the stagnation point) and the equilibrium total pressure (when the dispersed phase, either liquid droplets, or solid particles, is always at inertial and thermodynamic equilibrium with the continuous vapour phase). The presented analytical theory is a relation between nondimensional total pressure and Stokes number, representing particle size or inertia, and specifies the total pressure under different nonequilibrium conditions. One simple equation applies to diverse multiphase mixtures, solid particle laden gas as well as vapour-droplet mixtures, and at a wide range of flow conditions, both subsonic and supersonic. The associated issue of interpreting total temperature, and the relation between measured total pressure and entropy production in multiphase flows have been discussed at length by Guha (1998).

Download Full-text

An Evaluation of Material Weight and Contained Fluid Volume for Eccentric Intersecting Cylinders of Arbitrary Size

Journal of Pressure Vessel Technology ◽

10.1115/1.3265686 ◽

1989 ◽

Vol 111 (3) ◽

pp. 342-347

Author(s):

Y. J. Chao ◽

M. A. Sutton

Keyword(s):

Vessel Diameter ◽

Fluid Volume ◽

Wide Range ◽

Single Integral ◽

Material Volume ◽

Thin Walled ◽

Special Case ◽

Range Of Values ◽

Engineering Personnel ◽

Quantities Of Interest

Engineering personnel in industries which use pressurized containment vessels having attached nozzles are required not only to design portions of the lifting mechanism, but also to estimate the fluid volume which the vessel and nozzles will contain; most designers use simplified formulas for computing the quantities of interest. Typically, these formulas are valid approximations when the nozzle diameter is much smaller than the vessel diameter. The enclosed work develops three single-integral expressions which can be programmed and numerically integrated to obtain accurate estimates for both the material volume and also the containment volume present in a pair of eccentrically, or concentrically, intersecting thin-walled cylinders of arbitrary diameters. A table of such values is presented for a wide range of values of the standard nozzle pipe diameter and vessel diameter, for the special case of a concentric nozzle. In addition, an example is presented which compares the numerically integrated values for both the material volume and the containment volume to simplified upper and lower-bound estimates.

Download Full-text

Universities’ Intellectual Capital Report: The Formation Concept, Analytical Capabilities under Stakeholders Management Decisions-Making

Accounting Analysis Auditing ◽

10.26794/2408-9303-2020-7-6-40-54 ◽

2020 ◽

Vol 7 (6) ◽

pp. 40-54

Author(s):

A. A. Vakhrushina ◽

M. A. Vakhrushina

Keyword(s):

Intellectual Capital ◽

Practical Importance ◽

Economic Life ◽

Effective Management ◽

Ministry Of Education ◽

Systematic Analysis ◽

Accounting Systems ◽

Management Accounting Systems ◽

Wide Range ◽

Russian Universities

The modern trends in the socio-economic life, educational and research spheres lead to the increased attention of universities to the more effective management of available resources, as well as high-quality and relevant disclosure of information in their public reporting to the interested parties. Under the circumstances, the intellectual capital (IC) components become key objects in the management accounting systems, and the IC report may become one of the main engines to achieve the transparent information which can raise the interest of stakeholders. The analysis of this practice clarified the discussion points and helped to develop conceptual guidelines for the preparation of the IC report for Russian universities. There have been used the following methods to solve the problem, such as quantitative-systematic analysis, semantic grouping of results and logical relationships. The developed methodology for analyzing the report on IC universities has a certain practical importance. Such methodology also includes methods of financial and management analysis. The formulated recommendations are intended for a wide range of stakeholders, the leadership of the Russian Ministry of Education and Science and higher education institutions.

Download Full-text

New material-saving technologies of pipe rolling on pilgrim units

System technologies ◽

10.34185/1562-9945-6-131-2020-13 ◽

2021 ◽

Vol 6 (131) ◽

pp. 149-162

Author(s):

Valery Balakin ◽

Stanislav Stasevsky ◽

Yuri Ugryumov

Keyword(s):

Continuous Casting Machine ◽

Cast Billet ◽

Continuous Cast ◽

Centrifugally Cast ◽

Continuous Cast Billet ◽

Wide Range ◽

New Material ◽

Thin Walled ◽

Pilger Rolling ◽

Material Saving

In this work, based on the analysis of the process of hot pilger rolling of pipes of a wide range of sizes and grades from a round continuous cast billet, new and improved existing metal-saving technologies have been developed to reduce metal losses in the pilger head.Using scientific and patent sources of information in the field of pilger rolling and its mathematical modeling with the calculation of tables for rolling pipes of a wide range of sizes from a round continuous-cast billet with a diameter of 385-470 mm, metal losses into technological scrap on a pilgerstan are determined: a seed and a pilger head.On the basis of the results of the theoretical determination of metal losses in the process scrap on the pilgerstan: the seed and the pilger head, a forecast was made to reduce the weight of the pilger head, which was used to develop new material-saving technologies for pilger rolling of pipes, both thick-walled with D / S = 6 - 12.5, and thin-walled with D / S = 12.5 - 40. Metal losses in the pilger head are the main factor of increased metal consumption coefficients on pilger units, which reduces their competitiveness in comparison with other units when using round continuously cast billets as a starting material.The forecast for the reduction of metal losses in the pilger head made for the first time makes it possible to estimate the reserves for reducing the mass of the pilger head both by eliminating the underflow of the liner and trimming of the pipe end adjacent to the pilger head, and by means of individual parts of its profile part and predicting its decrease to the minimum possible size, ensuring the removal of the pipe from the mandrel using a gate device.To reduce the weight of the pilger head when rolling thick-walled pipes, it is recom-?ended to use improved technologies for butt-end rolling and rolling of the pilger head on the free section of the mandrel.The results of the studies and the proposed new material-saving technologies can be used on pilgrim units when rolling thick-walled (D / S = 6 - 12.5) and thin-walled (D / S = 12.5 - 40) pipes of a wide range of brands (carbon, alloyed, highly alloyed and special) from both continuous casting machine and forged and centrifugally cast billets, as well as ingots.

Download Full-text