Lyudmyla Dzyubyk

The paper examines the structural and technological requirements for improving the durability of welded joints used to attach knives to the twin-shaft shredder shafts. It is shown that, for such joints, the determining factors are not only the calculated size of the fillet weld, but also the geometry of its external profile, the nature of the transition from the weld metal to the knife body, the weld reinforcement height, the presence of undercuts, and the ability of the welded joint to ensure smooth force-flow transfer from the knife to the supporting bracket and shaft. Based on analyses of operational loads, finite element analyses, and expert assessments of new and worn shredder shafts, an approach is proposed to develop a rational profile for a multilayer weld by defining the geometric parameters of the weld reinforcement. The expediency of accounting for operational abrasive wear as a factor affecting external weld geometry is demonstrated, as it may, under certain conditions, reduce the geometric component of factors that cause stress concentration in the shaft structure.

The use of tracked (caterpillar) vehicles enables us to meet the requirements concerning harmless impact upon the environment, the considerable amounts of work to be fulfilled being saved. In particular, as compared to wheeled vehicles, there is less pressure upon the ground; there is also the opportunity to work in specific conditions of marshy, sandy, and low-bearing soils; stable performance in hard climatic conditions, etc. is also possible there. A necessary and important part of the tracked vehicle is its special suspension. Such a suspension contributes to smoother motion of the mechanism, it also cushions shocks, and ensures transmission of motion from the engine to the tracks. Independently of the design of the suspension, there are always several couples of support rollers. These rollers make up the intermediate link between the mover and the carrier frame, they transmit not only great weight but also the created loading, they guide the tractor’s caterpillars, etc. In the course of their work, the support rollers of tracked vehicles experience intensive wear and tear of the outer surface of their rims. As a result, changing them is necessary; dismounted ones are to be repaired. The use of restorative technology through overlaying (building up) by means of the electric arc is considered in this paper. This enables us to ensure cost savings and to repair support rollers of hardly loaded track vehicles. It is also possible to increase their serviceability by optimizing the overlayed metal; in particular, by increasing the hardness of the overlayed layer and increasing its resistance against impact and abrasive wear. The weldability of the main metal of a support roller has been analyzed. It is shown that the use of high-carbon material complicates the conditions for overlaying the outer rim. It is necessary to use pre-heating to high temperatures. This reduces the tendency of the material to form hardening structures and cracks after the overlaying. Investigations of peculiarities of overlaying a cylindrical surface of the rim of a tractor’s roller have been conducted. In particular, the limit values of the length of a weld pool depending on the diameter (value of wear) of the overlayed rim of a roller have been determined. It is shown that it is necessary to carry out the displacement of the arc from the zenith. This ensures the necessary formation of the weld-pool and the absence of spreading of the metal overlayed on the rim. The determination of the value of heat input of overlaying a roller has been carried out, the heat input is considered as a function of parameters of the electrode wire. Verification calculation of the obtained values of specific power for the permissible length of the weld-pool has been conducted. Concretization of the obtained results was carried out by taking into account the optimal range and permissible rate of cooling in overlaying the main material of a support roller. According to special nomograms, the dependence between the rate of cooling and the heat input of overlaying has been established. Especially, there were investigated the temperature conditions during overlaying the weld beads. It is shown that heating the roller takes place at the expense of neighboring weld beads. It is established that in overlaying at the determined values of heat input (per unit length) there can be achieved the temperature of auto heating is sufficient for the pre-heating of a roller.

Currently, there is a tendency to increase the depth of gaseous and liquid fossils extraction. Therefore, prospecting and developing new deposits is promising. There is also a need to create new freshwater sources and implement relevant geological work based on this need. It is essential to have information about the characteristics of the explored slabs and the geology of the fields in general. Implementation of engineering and geological core drilling exploration is the most acceptable and provides the necessary data. Here, the peculiarities of the technological schemes of the process implementation make it possible to obtain separate sections of structures at a depth of the drilling equipment. It is essential to use traditional equipment, recommended for decades and provides the necessary results [1–3]. In the drilling process, you can achieve different diameters and depths of wells execution, obtain fossil samples etc. Engineering and geological exploration drilling is now taking on increased use in various industries [3]. Therefore, the problem of providing high- quality drilling tools, the stability of their operating characteristics, and the possibility of usage in different conditions is an urgent need today. Modern drilling problems determine the usage of components of the core set with the appropriate physical and mechanical characteristics. Especially it relates to elements close to the drilling tool and the place of fossil; destruction – drill pipe. It is installed immediately after the crown core drill and receives almost the same loads and effects during working [1–3]. Conditions for the implementation of the process of core drilling are characterized primarily by the effect on the elements of the significant axial and twisted core set forces. There is the influence of the corrosive and active environment of the fossil in the washing and lubricating liquids well, etc. High temperatures are also observed at the drilling sites [3], which negatively affect the working tool and speed up its operation. As a result, there is an intensive shock, and abrasive core pipe wear and operation indicators change their constructive size. As a result, it is necessary to replace the operated drill string periodically. Considering modern technical and economic factors, it may be decided to repair a pipe to its original size in many cases. There are tasks for providing the appropriate characteristics of the core pipe surface. It is possible to model such properties of the new surface that functionally the best meet the conditions of the drilling process of a given geological formation. The peculiarities of applying the therapeutic layer on the surface of the core pipe are investigated in work. The experience shows that using electric arc surfacing under the flux layer is expedient. This provides the necessary adhesion of the applied layer and promotes obtaining resistance to the operation surface of the core pipe. At the same time, there is high-quality protection and the possibility of additional alloying through the flux-slaggy welding bath. Using electrode powder type wires creates conditions for flexibility to achieve the established characteristics of functional layers [4–6]. The filling flux, located in the cross-section of the electrode wire, can be easily changed by chemical composition. At the same time, it is possible to make relatively small parties of a wire with the set characteristics. The technological scheme justification about the core pipe surfacing is performed. It provides the previous displacement of the electrode butt size from the zenith of the core pipe to prevent the welding bath from spreading. The structural pipe size , the requirements for residual deformations, and the conditions of shapping the welded layer show the practicality of welding on a helix.

A stochastic game model of data clustering under interference conditions is proposed. An adaptive recurrent method and algorithm for stochastic game deciding have developed. Computer simulation of game clustering of noisy data has performed. The parameters influence on the stochastic game method convergence for noisy data clustering is researched. For this purpose, each data point is considered as a separate player with the ability to learn and adapt to the uncertainties of the system. After the selection of clusters is completed, all players calculate the corresponding losses by the criteria of minimizing the total distance between the cluster points formed by the free choice of player strategies. The results obtained are analysed. A stochastic approximation based on the mixed-strategy adjustment method minimizes the mean loss functions on single simplexes.

An effective theoretical-experimental approach to evaluation of wheel steels resistance to contactfatigue damage (spalling) formation by pitting mechanism is proposed. On the base of the results of experimental studies and calculations,...

At present, the use of power hydraulic cylinders is an integral part of most industrial equipment. They provide translational and horizontal movements, replacement of goods, fixation, etc. These devices are necessary elements of the equipment where application of the corresponding level of effort is applied. Often hydraulic cylinders are created specialized to perform certain types of work. It should be noted that part of the elements of the power cylinder in the manufacture is combined with welding. Such integral connections provide rigidity of installation, tightness of a design, fatigue strength at multicycle loadings. Difficult operating conditions, significant workloads, the presence of various external factors often leads to the destruction of individual elements of the cylinder. At the same time, the cost of repairing equipment that involves replacement with new power devices is quite high. This causes the implementation of repair and restoration work carried out at specialized enterprises. However, in the case of repairs, there are often a number of problems that require prompt resolution in the production environment. These should include the provision of basic materials with similar physical and chemical properties, the establishment of welding modes, the selection of the necessary welding materials, the use of appropriate techniques for conducting the arc process, etc. Therefore the repaired welded design of the case of the power hydraulic cylinder needs additional studying for weldability of separate elements among themselves, formation of a zone of thermodeformation influence. In general, the repaired hydraulic cylinder should meet the installation operating requirements depending on the purpose. The design of the considered hydraulic cylinder of the press installation is rather technological from the point of view of maintenance of automation of welding process. It contains long welds of a simple ring configuration. At the same time, the significant linear dimensions and the presence of a cylindrical surface cause some complexity in the implementation of processes. The construction material of the power hydraulic cylinder is low-carbon low-alloy steels. The analysis of technological weldability indicates a tendency to crack due to the thermal cycle of welding. The simulation of welds of the power hydraulic cylinder is performed in the work. The number of rollers was taken into account when obtaining butt welds. A comparative analysis of different electrode materials with different doping systems is done. The most applicable welding materials by chemical composition and properties of the weld metal are determined. According to the literature data and the results of comparative analysis, the optimal range of cooling rate of the main material of the hydraulic cylinder was established. The properties and structure of the zone of thermal influence of the butt welds of the power hydraulic cylinder have been studied. The magnitude of deformations and stresses caused by the thermal cycle of welding of the shell structure of the hydraulic cylinder liner is investigated. The admissible parameters of the zone of plastic deformations during butt welding are determined.