scholarly journals Scientific bases of the optimization of geometrical parameters of innovative telescopic working body of a bulldozer (on basis of general theories of cooperation of dump working bodies with environment)

Author(s):  
L. A. Khmara ◽  
R. M. Krol
2021 ◽  
Vol 12 (3) ◽  
Author(s):  
M. M. Gudzenko ◽  
◽  
V. P. Vasyliv ◽  
M. M. Mushtruk ◽  
M. M. Zheplinska ◽  
...  

In modern economic conditions, the chosen technology of raw material processing and the choice of the necessary equipment for both the line as a whole and the oil press are of great importance in oil production. In small-capacity workshops, screw presses of various designs are used. The twin-screw extruder occupied a certain niche among the press equipment with a productivity of 150–500 kg/h. Their use can significantly simplify the technology of oilseed processing. They combine operations of heat treatment, grinding, and pressing of vegetable oil. It is important to study the influence of geometric parameters of the oil pressure path and screw nozzle on the oil yield. In twin-screw extruders, it is rational to choose the pitch of the worm, the width of the channel between the turns, the width of the crest of the turn and the length of the nozzle with variable geometrical parameters. The analysis and selection of geometrical parameters of working bodies of a twin-screw extruder on the basis of theoretical calculations are carried out. Two sets of experimental working bodies with the changed geometrical parameters are made. Their theoretical degree of compression is determined, which is 5.50, 4.69, and 4.33, respectively. It is experimentally confirmed that the oil yield depends on the degree of compression due to the geometric parameters of the screw. The effect of a sharp drop in the free volume of the screw on the energy performance and press extruder performance has been revealed. The general nature of the change in the free volume in the areas of nozzle groups is accompanied by an uneven decrease of 40–80% towards the release of oil cake. The nature of the change in the free volume of turns along the length of the screw shaft characterizes the correctness of its design. The selection of rational geometric parameters of the working bodies should be considered in combination with other design parameters, which will intensify the process of oil pressing.


Author(s):  
В. М. Дворжак

Development and research of functionally-adequate target mechanisms of technological machines of light industry with application of applied CAE-programs. Used the apparatus of vector algebra; analytical and numerical methods for determining the position functions of planar mechanisms containing a structural group of the fourth class of the second order, based on the vector transformation of coordinates; random search method for metric synthesis of flat mechanisms; methods of computer visualization and animation of kinematic schemes of flat mechanisms of higher classes. Mathematical models describing the position functions of the mechanism of eyelets of a warp knitting machine containing a structural group of the fourth class of the second order with rotating kinematic pairs in the form of angles of moving links, free vectors constructed on these links and radius vectors of characteristic points of the mechanism as a function of the angle of rotation of the master crank. The geometrical parameters of the flat six-link mechanism of eyelets for the warp knitting machine containing the structural group of the fourth class of the second order with rotating kinematic pairs as a result of metric synthesis of the mechanism by random search in CAE-program are determined; computer circuit modeling of the obtained mechanism is performed; graphs of visualization and animation of the kinematic scheme of the received mechanism are constructed; identification of the kinematic scheme of the obtained mechanism for compliance with the accepted structure; the received graph of function of position of an auricular needle of the mechanism of the fourth class; the functions of the position of the eye needle of the new mechanism and the mechanism of the basic knitting machine OV-7 are compared. The structure of a flat six-link mechanism, containing structural groups of the fourth class of the second order with rotating kinematic pairs, is proposed for use as a drive in a warp knitting machine on the example of the mechanism of oscillating movement of eyelets. The geometric dimensions of the moving parts of the functionally adequate mechanism of the fourth class for the drive of the eye needles of the basic knitting machine are determined. Software blocks for automated computer metric synthesis and calculation of link angles and radius vectors of characteristic points of the mechanism in the CAE program have been created. Practical Value is to use the results for the design and construction of flat mechanisms of the fourth class with rotating kinematic pairs of warp knitting machines, in which the working bodies make stops during the work process.


2018 ◽  
Vol 64 (No. 4) ◽  
pp. 195-201
Author(s):  
Savelii Kukharets ◽  
Gennadii Golub ◽  
Viktor Biletskii ◽  
Oleksandr Medvedskii

The work is devoted to the issue of improving the quality of cultivating of root-bearing soil layer and optimizing its agrotechnological properties. Improving the quality of cultivation is due to the application of soil cultivating tools equipped with disk-knife working bodies. They are provided theoretical and experimental study of the work of the disk-knife working body, and it is substantiated its rational parameters. The basis of the substantiation of the parameters of the cultivating tool is the original analytical model, which reflects the process of interaction of the working body with the soil. To study the performance of the process, on the basis of kinematic equations of motion of the individual points of the working bodies, it is developed the analytical model of the motion of the battery of the working bodies. On the basis of the provided analytical researches, they were determined geometrical parameters and developed experimental samples of the disk-knife working body. It was carried out a comparative test in the field of tools equipped with disk-knife working bodies and with standard spherical cut-off discs, which confirmed the effectiveness of the use of disk-knife working bodies. The use of disk-knife working bodies ensures: the burying of plant remains and fertilizers into the root-bearing soil layer, improving the quality of soil cultivation, preserving of its structure, reducing the traction resistance of the body.


Author(s):  
Viktor Deikun ◽  
◽  
Dmytro Artemenko ◽  
Svitlana Deikun ◽  
◽  
...  

The aim of the work is to substantiate the geometric parameters of the distributor, which are able to provide the maximum range of fertilizer particles in the subclavian space, based on the analysis of all factors affecting the material particles during their transportation to the surface of the distributor. The result of research is to achieve a uniform distribution of fertilizers on the width of the capture and, accordingly, on the area. It is known that the particles of material sent in accordance with the given trajectories in the pre-provided areas of the surface of the furrow formed by the working body, in contact with the soil are significantly redistributed and the meaning of the traditional approach to uniformity is completely lost. In addition, it is necessary to take into account that for placing fertilizers in the soil, in most cases, flat-cutting working bodies are used. For normal operation, in terms of deepening into the ground, they must be installed with a forward tilt at an angle of up to 3°. As a result, the bottom of the furrow, which they form, acquires a conical shape with a slope to the center. In this case, it becomes obvious that the material must be fed not evenly across the width of the working body, and most of it to be directed at a clearly defined distance in the direction perpendicular to its axis. The numerical value of this distance is determined by the nature of the redistribution of the granules as a result of contact with the soil. In the process of rolling the granules or particles to the center, the uniformity of distribution will be restored. In this case, it becomes obvious that the material must be fed not evenly across the width of the working body, and most of it to be directed at a clearly defined distance in the direction perpendicular to its axis. The numerical value of this distance is determined by the nature of the redistribution of the granules as a result of contact with the soil. In the process of rolling the granules or particles to the center, the uniformity of distribution will be restored. In this regard, there is a need to solve the problem of ensuring the maximum range of particles in the transverse direction using the simplest geometry of the distributor surface. In our opinion, such a surface can be a prism. In the article the results of theoretical research of process of portage and distributing of granules of mineral fertilizers are resulted after a reflection from the plane of reflection in sub paw space of trivial cutting of working organ. Geometrical parameters and corners of location of reflecting plane are grounded. The obtained dependences allow to reasonably establish geometrical parameters of the distributor which will provide the set range of flight of particles of material for working bodies of various width of capture and to reach desirable result taking into account laws of their redistribution at contact with soil.


2020 ◽  
pp. 34-42
Author(s):  
Thibault Chastel ◽  
Kevin Botten ◽  
Nathalie Durand ◽  
Nicole Goutal

Seagrass meadows are essential for protection of coastal erosion by damping wave and stabilizing the seabed. Seagrass are considered as a source of water resistance which modifies strongly the wave dynamics. As a part of EDF R & D seagrass restoration project in the Berre lagoon, we quantify the wave attenuation due to artificial vegetation distributed in a flume. Experiments have been conducted at Saint-Venant Hydraulics Laboratory wave flume (Chatou, France). We measure the wave damping with 13 resistive waves gauges along a distance L = 22.5 m for the “low” density and L = 12.15 m for the “high” density of vegetation mimics. A JONSWAP spectrum is used for the generation of irregular waves with significant wave height Hs ranging from 0.10 to 0.23 m and peak period Tp ranging from 1 to 3 s. Artificial vegetation is a model of Posidonia oceanica seagrass species represented by slightly flexible polypropylene shoots with 8 artificial leaves of 0.28 and 0.16 m height. Different hydrodynamics conditions (Hs, Tp, water depth hw) and geometrical parameters (submergence ratio α, shoot density N) have been tested to see their influence on wave attenuation. For a high submergence ratio (typically 0.7), the wave attenuation can reach 67% of the incident wave height whereas for a low submergence ratio (< 0.2) the wave attenuation is negligible. From each experiment, a bulk drag coefficient has been extracted following the energy dissipation model for irregular non-breaking waves developed by Mendez and Losada (2004). This model, based on the assumption that the energy loss over the species meadow is essentially due to the drag force, takes into account both wave and vegetation parameter. Finally, we found an empirical relationship for Cd depending on 2 dimensionless parameters: the Reynolds and Keulegan-Carpenter numbers. These relationships are compared with other similar studies.


Author(s):  
I. G. Shubin ◽  
A. A. Kurkin

During manufacturing nuts of increased height, a problem of obtaining correct cylindrical form of the hole for thread and overall geometrical parameters arises. To solve the problem it is necessary to know regularity of the blank forming process. Results of the study of a technological process of high hexahedral nuts forming presented. The nuts were M18 of 22 mm height, M16 of 19 mm height and M12 of normal height 10 mm according to GOST 5915–70, accuracy class B, steel grade 10 according to GOST 10702–78. The volumetric stamping was accomplished at the five-position automatic presses of АА1822 type. It was determined, that unevenness of the metal flow in the process of plastic deformation of blanks of increased height nuts was caused by different stress conditions by their sections. To simulate the mode of deformation, the program complex QForm-3D was chosen. The complex ensured to forecast with necessary accuracy the metal flow in a blank, as well as to define the deformation force and arising stress in the working instrument. The simulation showed the presence of regularity between preliminary formed buffle and deviation of dimensions and form of a blank wall after its finishing piercing, which can be expressed by a nonlinear dependence. The limit values of the relative height of the buffle С/D = 0.56–0.588 defined, exceeding which will result in rejection of the finished product. Accounting the limit values of the relative height of the buffle will enable to correct a mode of technological operations and technological instruments at stamping of high hexahedral nuts.


2017 ◽  
Vol 13 (2) ◽  
pp. 33-42
Author(s):  
Ye.V. Shapovalov ◽  
◽  
V.O. Koliada ◽  
D.D. Topchev ◽  
N.F. Lutsenko ◽  
...  

Author(s):  
B. P. Khozyainov

The article carries out the experimental and analytical studies of three-blade wind power installation and gives the technique for measurements of angular rate of wind turbine rotation depending on the wind speeds, the rotating moment and its power. We have made the comparison of the calculation results according to the formulas offered with the indicators of the wind turbine tests executed in natural conditions. The tests were carried out at wind speeds from 0.709 m/s to 6.427 m/s. The wind power efficiency (WPE) for ideal traditional installation is known to be 0.45. According to the analytical calculations, wind power efficiency of the wind turbine with 3-bladed and 6 wind guide screens at wind speedsfrom 0.709 to 6.427 is equal to 0.317, and in the range of speed from 0.709 to 4.5 m/s – 0.351, but the experimental coefficient is much higher. The analysis of WPE variations shows that the work with the wind guide screens at insignificant average air flow velocity during the set period of time appears to be more effective, than the work without them. If the air flow velocity increases, the wind power efficiency gradually decreases. Such a good fit between experimental data and analytical calculations is confirmed by comparison of F-test design criterion with its tabular values. In the design of wind turbines, it allows determining the wind turbine power, setting the geometrical parameters and mass of all details for their efficient performance.


2020 ◽  
Vol 22 (4) ◽  
pp. 1061-1076
Author(s):  
Wafa Bensmain ◽  
Mohammed Benlebna ◽  
Boualem Serier ◽  
Bel Abbes ◽  
Bachir Bouiadjra

AbstractOsseointegration is a fundamental phenomenon of dental implantology. It ensures the stability, the safety and the durability of dental implants and predictable clinical success in long-term. The geometric form of the implant is a defining parameter of osseointegration and implant-bone charge transfer. This is the essential constitutes of this study. In fact, we demonstrate using the finite elements method with tridimensional numerical computations, that the geometrical parameters of the implant conditionate the level and the repartition of the stresses, induced in the cortical bone and the spongy bone during the masticatory process, simulated here by dynamic charging. The effect of several parameters [size and conicity of the implant neck, size and radius of curvature of the implant apex] and the shape of the implant corps on the biomechanical behavior of the bone. The latest was analyzed in terms of variation of the equivalent stress induced in the bone. The purpose of this analysis was the developing of an implant form allowing stress relaxation, during the mastication process, in the living tissue.


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