INSPECTION AND STRENGTHENING OF COASTAL AREAS, COASTS, SEAS AND RIVERS OF THE ROSTOV REGION

In modern society, an important role is assigned to the protection of water protection zones, reservoirs, rivers and seas, because they are the main areas of life and recreation of the population. In the Rostov region they are: the coasts of the Black and Azov seas; Tsimlyanskoe, Manochevskoe, Veselovskoe reservoirs; the Don River and others, which requires the creation of new technical solutions for bank protection using composite heterogeneous multilayer structures that form a leveled complex bank, will determine the rational shape of the side walls of the junction of the streams. This requires the creation of design parameters for them.

A Form-Finding Method for Branching Structures Based on Dynamic Relaxation

Branching structure is often used as a supporting structure of the grid shell due to its geometrical and force-transferring features, and the rationality of its shape is very important. The “physical” and “numerical” hanging models can be used for the joint form-finding of the branching structure and free-form grid shell. However, slack elements may exist in the equilibrium model which corresponds to the inefficient members in the form-found branching structure. To solve this problem, a form-finding method of branching structure based on dynamic relaxation is proposed in this study. The proposed method clusters the elements of the branching model and equalizes the axial forces of the elements in the same cluster, in other words, there are no slack elements in the equilibrium branching model. This method overcomes the defect that the equilibrium branching model may have slack elements and needs many manual adjustments during the procedure of determining the rational shape of a branching structure, and effectively prevents the inefficient members existing in the form-found structure. Numerical examples are provided to demonstrate the characteristics of the proposed method and its effectiveness is verified as well.

The inverse task solution for the calculation of sweeps of sheet parts by integral geometry

This article deals with the search for a rational semi-finished product for parts of the integral form. Here a variant of the solution of the given problem is described based on the inverse solution of the mathematical problem. The reasons and the nature of the problem occurring in standard approaches to the calculation of the semi-finished product are shown using the example of two parts with aerodynamic curvature. The material and sheet thickness of the components are selected to suit the application. The forming process is also the same as the initial situation. The rational shape of the part can be found using the optimization solution based on the discrepancy of the contours with respect to the sweeps of the dynamic calculation and the CAD model. The new shape of the blank makes it possible to realize the forming process of the parts with minimal deviations from the contour of the 3D model.

Determination of Rational Design and Geometric Parameters of a High-Performance Drill Based on a Mathematical Model of the Cutting Part

Processing of high-precision holes in one technological operation is an urgent problem of advanced manufacturing. Processing of precise holes in parts for aerospace and machine-building industries with a diameter of up to 30 mm is performed during countersinking, deployment or grinding operations. These operations are applied only if there already exists a pre-treated hole. Monolithic three-fluted drills have been becoming common for processing high-precision holes of 7-8 quality over the last few years. The processing of various types of materials such as stainless steels, cast iron and heat-resistant steels requires rational geometric and structural parameters of the cutting tool. The nature of the load distribution between all the teeth during drilling plays a huge role in the processing efficiency. Even load distribution between the three teeth and a positive geometry improves self-centering and reduces the deviation from the specified axis of the hole. The drill sharpening provides positive geometry along the entire main cutting edge. The influence of the geometric parameters of the cutting edge of the screw groove on the shape of the drill bit is equally important. Existing approaches to the design of the thinning do not account for the influence of the geometric parameters of the cutting edge on the section of the screw groove. Analytical approaches to modelling of the main cutting edges are typically married with difficulties associated with achieving a smooth change in the angle of inclination to the tangent of the cutting edge. The complexity of the aforementioned task is largely due to the presence of critical points at the interface of the spiral groove and thinning. Determining the rational shape of two sections of the main cutting edge performed in this study is a complicated task that includes several steps needed to find the number of nodal points. Achieving a positive rake angle in the normal section to the cutting edge at the gash area that was formed via a special sharpening is one of the most important results of this paper. The rational shape of the cutting edge and the front surface provides an increase in the strength of the cutting part by 1.3 times.

DETERMINATION OF THE RATIONAL SHAPE AND PARAMETERS OF THE ARTICULATION OF THE SPLIT COLLET OF THE CLAMPING MANDREL TO EXPAND ITS TECHNOLOGICAL CAPABILITIES

The object of research is perspective mandrels with the pince fendues used for installing blanks such as rings, bushings and cups. These machine accessories are both high-precision and wide-range, but in previous articles it was found that there are reserves for expanding their technological capabilities. It was found that the shape and size of the articulation are key parameters and they significantly affect the allowable compression of the collet and its strength. Therefore, in this article, the finite element method solves the problem of determining the rational shape and parameters of the articulation to increase the compression of the collet while maintaining strength. Based on the manufacturability of the split collet articulations, various forms of articulations are considered by the method of iteration from the traditional rectangular to the idealistic semicircular. The configuration of the articulation shape, the chamfer angle that bevels a right angle in a traditional design, and the chamfer size varied. As a result of calculations, the maximum stresses and displacement of the ends of the articulation, which provides its compression were determined. This compression allows increasing the base diameter of the collet when loading, and the stresses ensure the strength of the collet. Two rational forms of collet articulation that have practical interest are defined. The first form, which is the easiest to manufacture, has a 45° chamfer and, with equal strength, provides almost 15 % more compression of the collet than for a traditional design. The second form, which is more difficult to manufacture, has chamfers of 30° and 60° and with equal strength provides 30 % more compression of the collet.

RESEARCH OF THE AUTOMATED DYNAMIC RECONFIGURABLE PANEL

A computer model of a fragment of an automated dynamic reconfigurable panel is being developed and researched. The stresses, displacements, and deformations arising at various loads are investigated. The results of computer research allow you to choose a rational shape and configuration of the panel, which leads to an increase in its strength characteristics and weight reduction.

Application of solar maps to select a rational shape of the shading device for the tractor cabin

The article is devoted to the use of solar maps to determine the period of unwanted insolation and the amount of thermal radiation that penetrates into the tractor cabin throughout the entire working day. In addition, an optimal form of a sun-protection device has been proposed, which makes it possible to reduce the magnitude of the exposure dose of thermal radiation affecting the operator. Since solar radiation makes the main contribution to the heat balance of the cabins of mobile machines (tractors, combines, etc.), the results obtained can mainly be used in assessing the working conditions of operators and in calculating and choosing systems for normalizing the microclimate (ventilation and air conditioning).

Main the Oretical Provisions of Grain Material Separation in Air Channels with Unequal Air Flow Speed

The article considers the increase of efficiency of grain materials separation in pneumatic vertical channels by determining the rational shape and parameters of material supply, as well as the geometric shape of the pneumatic channel and options for separation into fractions. Regularities of change of trajectory and speed of movement of material in pneumatic vertical channels of round section with the lower unloading of material are received. The regularities of particle motion in the form of a material point were determined taking into account air resistance forces, friction forces, Magnus and Zhukovsky forces, material moisture and density based on a theoretical study of grain fractionation in pneumatic vertical channels. Using the proposed dependences for the design of air separators, it is possible to determine the initial rate of introduction and the direction of entry of grains into the air stream, which are the initial conditions for determining the trajectory of material in air channels with lower material discharge.