scholarly journals NUMERICAL CALCULATION OF THE HYDROLIQUID LEAKAGE THROUGH THE RADIAL CLEARANCE OF THE CONNECTED ELEMENTS ON THE TOWER CRANE HYDROCILINDER

2019 ◽  
Vol 16 (1) ◽  
pp. 18-30
Author(s):  
D. A. Potakhov ◽  
Ya. S. Vatulin

Introduction. The authors present the numerical calculation of the hydro-liquid leakage throughthe radial clearance of the “piston - hydraulic cylinder” conjugate node on the basis of determiningthe sealing elements’ resource of the tower crane hydraulic cylinder.Materials and methods. The authors use the method of mathematical modeling, which makes it possible to model the containing elements’ interaction of different physical nature on the unified methodological basis. Moreover, the paper presents such simulation systems as Simulation (finite element method), Flow Simulation (finite volume method) of the SolidWorks CAD program and Simulink Matlab with expansion packs.Results. As a result, the authors demonstrate the three-dimensional and irregular cross-section conjugation model of the radial clearance in the “piston - hydraulic cylinder” conjugate node. In addition, the authors propose the calculating method of the hydraulic cylinder tightness. Such method establishes the following scheme: “load on the hydraulic cylinder —number of operating cycles — uneven radial clearance between the piston and the liner — amount of fluid leakage — shrinkage of the rod”.Discussion and conclusions. The results of the research make it possible to increase the reliability of the power hydraulic cylinders of the road construction machines and equipment.

2020 ◽  
Vol 17 (1) ◽  
pp. 44-56
Author(s):  
D. A. Potakhov

Introduction. The contact interaction of the associated elements of the hydraulic cylinder (piston with sleeve, guide sleeve with cylinder and rod) determines the reliability of the reciprocating hydraulic motor. Assessing the effect of gaps of articulated hydraulic cylinder elements is an urgent task in view of the fact that the formation of gaps is inevitable, since friction is always accompanied by tribological wear processes. The paper investigates the determination and assessment of the influence of the gaps of the hydraulic cylinders’ mating elements on the stress-strain state of the contacting bodies on the example of the hydraulic cylinder for the Sokol 80.01 railway crane.Materials and methods. The author used the finite element method implemented in the Simulation SolidWorks module. Moreover, the author applied the Huber–Mises criterion as a criterion for the material plasticity. The paper also considered theoretically possible spatial design schemes of loading and depending on the type of the mating elements’ contacting of the hydraulic cylinder.Results. As a result, the author presented plots and graphical dependences, which were three-dimensional surfaces constructed according to the results of numerical experiments. The calculations took into account the joint deformation of the piston, sleeve, rod, guide sleeve and supporting guide rings of the hydraulic cylinder. The author carried out the analysis of the obtained diagrams and dependences of the contact interaction of the hydraulic cylinder for various options of the elements contacting. The paper presented the results that were useful for studying all types of hydraulic cylinders and working equipment of the road, construction and hoisting-andtransport machines.Financial transparency: the author has no financial interest in the presented materials or methods. There is no conflict of interest.


Author(s):  
Shinichiro Kajii ◽  
Naoki Sawa ◽  
Nobuhiro Kunitake ◽  
K. Umeki

A three-dimensional (3D) seismic isolation system for FBR building is under development. The proposed vertical isolation system consists form hydraulic cylinders with water-based liquid and accumulators to support large vertical static load and to realize low natural frequency in the vertical direction. For horizontal isolation, laminated rubber isolator or sliding type isolator will be combined. Because the major part of the feasibility of this isolation system depends on the sealing function and durability of the hydraulic cylinder, a series of feasibility tests of the hydraulic cylinder have been conducted to verify the reliability against seismic load and seismic motion. This paper describes the specification of the seismic isolations system, seismic response characteristics and the results of the feasibility tests of the seal. This study was performed as part of a government sponsored R&D project on 3D seismic isolation.


2019 ◽  
Vol 8 ◽  
pp. 1-18 ◽  
Author(s):  
Thomas Eggers-Kaas ◽  
Jesper Borre Pedersen ◽  
Christian Steven Hoggard ◽  
Florian Sauer ◽  
Jan Hilgart ◽  
...  

 During road construction work, material attributed to the Final Palaeolithic was discovered at Skovmosen I, near Kongens Lyngby on Zealand, eastern Denmark. Although it is regularly mentioned in reviews of the southern Scandinavian Final Palaeolithic, the Skovmosen I assemblage has hitherto remained poorly described. We here review the site’s discovery history and its context. Aided by a three-dimensional digital recording protocol, this article details the assemblage composition and its technology. The assemblage is comprised of tanged points, scrapers and burins, alongside blades and cores as primary reduction products. Although evidently disturbed by the road construction that led to the site’s discovery, the material likely reflects the remains of a small Final Palaeolithic locale, where diverse activities were carried out.


Author(s):  
R.Yu. Sukharev ◽  

The construction of highways is a complex, multi-stage process. Most of the construction works are carried out according to the projects of structures and quite high requirements are imposed on the quality of execution. The fulfillment of these requirements is associated with great difficulties in view of the limited accuracy of the road construction machine itself, the lack of on-board control systems and the limited capabilities of the human operator, who is unable to determine the required exact parameters of the structure being built «by eye». To meet the requirements, three-dimensional control systems are used, which allow determining 3 coordinates of the working order of the machine – the vertical coordinate and the location of the machine on the construction site. At the same time, the digital project of the constructed structure should be the setter in such a system. The system determines the current position and compares it with the project. On the basis of this information, a control effect on the operating organ of the machine is formed. The course of movement and the speed of the machine when using such systems are determined by the machine operator. Further development of these systems should be four-dimensional systems – in which all control actions are assigned to the control system, starting from calculating the trajectory of the machine, choosing the speed, determining the required number of passes and ending with controlling the position of the working body of the machine at each moment of time. For the functioning of these systems, adequate mathematical models of the turning processes of road construction machines with different steering options are necessary.


2019 ◽  
Vol 6 (3) ◽  
Author(s):  
Nikolai Tokar ◽  
Zelgedin Mevlidinov ◽  
Tatiana Levkovich ◽  
Alexandr Foevtsov

The work is devoted to ways to improve the efficiency of preparatory and excavation works in road construction using bulldozers equipped with universal working equipment. Studying the state of the bulldozer Park of road construction organizations of the city of Bryansk and the Bryansk region, it was revealed that the Park contains obsolete bulldozers. In this paper, the authors proposed options for improving the university of the working equipment of the bulldozer with the addition of a controlled knife system or controlled lower sections. At the equipment-driven knife system, the working equipment of the bulldozer is characterized in that the edges of the bottom of the blade of the inserted knife system imposed on the surface of the blade, consisting of metal sheets with cutting edges, stiffeners and connected to gidrol linkami their management by means of brackets , and with a blade – with the help of duosonics, hydraulic cylinders control the cutter systems, BAP-pyatsya the edges on the back side of the blade with eyes limited to residing their turn to increase the rigidity of the structure. If necessary, the cutting knives can be replaced with a cargo fork to effectively pick up the goods. When the equipment controlled the lower sections of the working equipment is characterized in that the push bars have cutouts for the installation of cross beam and pivotally connected via axles to the main building-som of the blade, which has a pivotally mounted visor with snarling face and eyes with hydraulic cylinder control. The lower sections are connected to the lever by means of hinge rods. The expansion of technological capabilities is achieved through the installation of an additional module-a loosening tooth with a tip or a cargo fork.


2014 ◽  
Vol 630 ◽  
pp. 234-239 ◽  
Author(s):  
G.A. Bondarenko ◽  
V.N. Baga ◽  
I.A. Bashlak

The paper studies the labyrinth seals of centrifugal compressor profit-proved stages using modern methods of numerical and physical modeling of the centrifugal compressor stages. A series of studies of the effect of operational and geometrical parameters on the maze, namely the quantities of the packed differential pressure, speed, fluid, geometric parameters of the seal, the magnitude of the eccentricity and radial clearance swirl flow at the inlet of a seal, etc. The technique of physical modeling seal has been specified. Research was conducted in two phases: numerical simulation using complex software Flow Vision and receiving data on a universal test bench to study the labyrinth seals.. A three-dimensional model of the labyrinth seal has been created, its verification by "known data has been held.. Integral characteristics in the form of distribution of flow velocities and pressures, flow visualization were obtained. Results of studies made ​​it possible to refine the workflow and introduce amendments to the known calculation formula for a more accurate calculation of leakage through the seal, subject to a number of additional factors that were not previously taken into account


2011 ◽  
Vol 261-263 ◽  
pp. 1119-1123
Author(s):  
Zi Jian Wang ◽  
Sheng Xie Xiao

This article in a typical road slope model as an example, through large-scale general-purpose finite element simulation software ANSYS/LS-DYNA rockfall on the slope of the roadbed impact for three-dimensional dynamic analysis in the roadbed, slope geological parameters and falling stone initial state is not at the same time on the roadbed impact the results of comparative analysis. The result is the mountain slope of the road construction project provides reference.


2011 ◽  
pp. 19-33
Author(s):  
A. Oleinik

The article deals with the issues of political and economic power as well as their constellation on the market. The theory of public choice and the theory of public contract are confronted with an approach centered on the power triad. If structured in the power triad, interactions among states representatives, businesses with structural advantages and businesses without structural advantages allow capturing administrative rents. The political power of the ruling elites coexists with economic power of certain members of the business community. The situation in the oil and gas industry, the retail trade and the road construction and operation industry in Russia illustrates key moments in the proposed analysis.


Author(s):  
Л.Н. Крячко

Постановка задачи. Изучение предмета «Иностранный язык» в техническом университете предполагает усвоение обучающимися терминологической лексики в соответствии с выбранной специальностью. Опыт преподавания показывает, что студенты испытывают трудности, связанные с запоминанием терминологических единиц и употреблением их в речи. Использование на занятиях по иностранному языку приема обучения терминологической лексике посредством опоры на внутреннюю форму данных лексических единиц позволяет оптимизировать процесс усвоения обучающимися специальных терминов. Результаты. Проведенное исследование дает основание утверждать, что анализ внутренней формы образованных семантическим способом англоязычных терминов специальности «Автомобильные дороги» позволяет выявить деривационно-ассоциативную связь терминологических единиц с лексикой общенационального языка, послужившей основой для вторичной номинации. Данные лексические единицы в большинстве случаев представляют собой хорошо знакомые студентам слова, обозначающие части тела человека и объекты, находящиеся в его близком окружении : одежду, посуду, инструменты, явления природы, представителей животного мира и т.д. Выводы. Ознакомление студентов дорожно-строительной специальности с внутренней формой изучаемых англоязычных терминов, выявление ассоциативных связей терминологических единиц со знакомыми студентам и широкоупотребительными словами общенационального языка, а также выполнение в аудитории специально разработанных тренировочных упражнений помогают снять трудности усвоения обучающимися терминологической лексики и облегчают ее запоминание. Statement of the problem. The study of the “Foreign Language” subject at a technical university involves students’ learning the terminology in accordance with the chosen specialty. The teaching practice shows that students experience the difficulties associated with memorising terminological units and using them in the speech. Applying the method of teaching the terminology based on the internal form of these lexical units at foreign language classes makes it possible to optimise the process of learning special terms by students. Results. The research that has been carried out gives reason to argue that the analysis of the internal form of the English “Automobile roads” specialty terms created in the semantic way makes it possible to reveal the derivational and associative relations of the terminological units with the national language words which served as the basis for the secondary nomination. In most cases, these lexical units are the words that are well known by the students and indicate the parts of man’s body and the objects that are present in man’s immediate environment: clothing, dishes, tools, phenomena of the nature, representatives of the animal world, etc. Conclusion. Introducing the internal form of the studied English terms to the road construction specialty students, identifying the associative relations of the terminological units with the well known to the students and widely used words of the national language, fulfilling the specially developed training exercises in the classroom help the students to overcome the difficulties of learning the terminology and to facilitate its memorization.


Author(s):  
M.A. Piskunov ◽  

Russian forest sector forms an attractive market for harvesting and logging equipment, however the position of Russian manufacturers is extremely weak. A brief overview of the current state of the market is presented with reference to the open sources. Its features are mentioned as compared to the road construction and agricultural machinery sectors. Three transnational companies dominate the Russian market of harvesting and logging equipment: John Deere, Ponsse and Komatsu. Most of the purchased equipment falls on machines for cut-tolength technology, such as harvester and forwarder. The market volume of new machines is estimated at 330–420 forwarders, 165–300 harvesters, about 30–40 feller bunchers and the same number of skidders. There were two waves in the consolidation of the position of foreign companies in Russia. The first was connected with the delivery of equipment and the development of foreign brands in Russia against the background of still high-profile positions of Russian manufacturers in the market. The second is the takeover of enterprises having a service network and reputation by diversified transnational corporations. The main strategies of the leading companies in the current situation are the export of equipment to Russia and the development of a service network. Companies do not turn to another level associated with the opening of production sites or joint ventures for the production of harvesting and logging machines. The Russian market is characterized by the absence of a strong Russian manufacturer of harvesting and logging machines, which is ready to significantly influence or actively participate in the processes of import substitution. The position of such a manufacturer is gradually occupied by the Belarusian Amkodor Holding. The purchase of new harvesting and logging machines can afford major timber companies. The main production sites of harvesting and logging machines are located in Finland, Sweden, USA, and Canada. In order to support forestry machine engineering, in addition to economic measures of stimulation approved in other sectors, it is proposed: to organize the work of scientific forest engineering centers on the base of public-private partnership with the financial support from the major vertically-integrated timber corporate groups; to stimulate the development of Russian sector-specific information technologies for harvesting and logging; to initiate the partnership with companies from the People’s Republic of China to launch the design and production of new-generation harvesting and logging machines.


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