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A fragment of cylinder block mating surface shape accuracy deviations measurement result. 10. ábra Mérési eredmény hengerblokk felületi megmunkálási alakpontosságának eltérésére.
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Citations
... Paper [21] deals with the corrosion protection of steel pipes in petrochemical production. Maksarov et al. paid much attention to improving the quality of the further processing of welded products [22][23][24][25]. Paper [26] is devoted to corrosion investigations in the atmosphere. ...
Corrosion processes of the most common steel grades in various environments are the subject of numerous studies. At the same time, the corrosion of welded joints hidden in concrete thickness has not yet been studied. The authors set themselves the task of investigating this process. For this purpose, the corrosion resistance of several metals (grade St.3, U7 and their weld joints) was studied in standard test solutions, simulating a concrete pore liquid, containing sodium carbonates and hydrocarbonates, and sodium chlorides. Data on comparative corrosion resistance in saline media for specified materials were obtained. It was shown that the corrosion rate depends on the ease of CO2 ingress into the solution, and, to a lesser degree, on the metal microstructure. The surface character of the metal samples and the composition of corrosion products were investigated by scanning electron microscopy and an X-ray diffraction analysis. Chemical forms of surface compounds were determined. For the first time, it is clearly shown that the electrode coating flowing during welding does not always protect the weld from corrosion, as was previously believed. The corrosion rate, in this case, is just the same as at the surface of the metal plate of a similar composition. In the conclusion of this work, it is emphasized that in the case of alkaline and chloride-containing media, the protective coating falling from the electrode to the weld does not protect it sufficiently from corrosion.
... The issue of ensuring technical compatibility at each stage of the life cycle is relevant for all technical systems [5][6][7][8][9][10][11], since non-compliance with the requirements for technical compatibility can lead to significant deviations of processes and a decrease in the quality. ...
The article considers the issue of ensuring compatibility in the implementation of the life cycle processes of technical systems. A logical diagram is given explaining the reasons for the decline in the quality of objects due to insufficient attention to the requirements for technical compatibility. On the basis of static calculations, the possibilities of improving the quality of systems of electric shut-off valves are presented due to the correct provision of technical compatibility of the form “product - lubricant”. Alternative options for combining valves and electric drives with reduced power and weight characteristics are proposed.
... For this reason, transiency arises in the variability of both kinds of forces because of an elastic force pressing the tool away from the workpiece, bringing about oscillation of the MPS and the emergence of an auto-oscillation process. The fact that the occurrence of self-excited oscillatory processes in a closed system brings about deterioration of workpiece roughness is generally known [1], [6]. Therefore, solving the problem of vibration suppression in a MPS is an important research mission. ...
This Publication has to be referred as: Olt, J[ueri]; Maksarov, V[iacheslav] & Efimov, A[leksandr] (2018). Abstract The authors of this article identify the influence of a gradient structure on the dynamic characteristics of a production process system and surface roughness taking shape during machining. Such a task is due to the finishing operation used in most production processes. Embedment of abrasive particles into the surface layer of a workpiece is an irreversible effect of its charging by a grinding wheel. At the running-in stage, mating surfaces are severely worn because of abrasive micro particles, deteriorating performance properties of parts. In this regard, we have proposed a new approach to achieving specified surface quality based on auto-oscillation process suppression during machining by combined destruction of gradient structure in a local chip formation region. It was established that using this method reduces auto-oscillation amplitudes, and therefore improves Ra surface roughness parameter value 1.65 times. This allows to exclude the grinding operation from manufacturing process when the specified quality parameters are reached.
... Internal factors and external influences arising from the functioning of the machine's mechanical system lead to the appearance of various types of fluctuations, which worsen the conditions of normal exploitation of the equipment, reduce the accuracy of operations, distort the trajectories of the working elements [3,4,5,6]. ...
... The analysis of torsional fluctuations is of great importance for the solution of the problem of increasing the accuracy of machining on CNC machines. These torsional fluctuations appear in the main motion and feed rate drives during start-up, during acceleration or deceleration, related to changes in the direction of motion, as well as during the engaging of tools into the work-piece material [3,5,6,7,8,10]. The methods of technological quality assurance and wear resistance implemented during the production of structural elements of production equipment are also essential for reducing vibration activity during the operation of the machines [9, 10]. ...
Own fluctuations in the drives of technological equipment based on a three-mass model of fluctuating torsional chain system are analyzed. Differential equations of motion of a mechanical system with three degrees of freedom are obtained. An analysis of the forms of fluctuating processes in the system is conducted. Conditions of orthogonality of own torsional fluctuation forms are considered, dependencies of own frequencies on system rigidity coefficients are determined.
... Mechanical system components are primarily subject to different types of vibration. Occurring oscillations lead to essential distortions of the set functions of program movement of working elements, reduce accuracy in processing of products and worsen other conditions of normal operation of the equipment [5,6,8,14,15]. ...
... Increase of rigidity of the mechanical system "machine-tool-detail", reduction of friction forces in feed drives, selection of optimal cutting modes for areas with reduced vibration levels, application of software algorithms and design solutions for vibration MEACS2018 IOP Conf. Series: Materials Science and Engineering 560 (2019) 012015 IOP Publishing doi:10.1088/1757-899X/560/1/012015 2 damping are the main ways to solve the problem of improving the accuracy of machining on CNC machines [3,[5][6][7]10]. ...
The article describes the principles of building dynamic models of technological systems with concentrated parameters with a finite number of degrees of freedom. Dynamic properties of technological system are considered taking into account elastic and inertial parameters of its elements. The model of three-mass torsional chain system and the model with progressively moving masses are used for estimation of vibrational processes in drives of the technological equipment. According to the proposed mathematical model the analysis is carried out and the forms of natural oscillatory movements in the system are revealed. Oscillations of zero, first and second eigenfrequencies are determined, for each of which sets of form of the coefficients are found that describe the system configuration in the process of free oscillations.
... The physical properties of deformed metal can be described in the form of an adequate mechanical model, constructed as a composition of mechanical elements such as elasticity, viscosity and plasticity [1]. Considering combinations of linear elastic springs, linear viscous dash-pots and elements of plasticity one can build a model which gives an observable perspective reflecting the nature of material removal process, changes in deformation and stresses of material and their dependence on the structure [2], [3], [4]. Many real metals combine behaviors of all these elements and it is possible to consider the stressstrain state of metal under the action of external loads. ...
... We describe the process of chip formation with the help of the rheological model proposed by Veitz and Maksarov [9]. This model is constructed as combination of two rheological bodies connected in series: the elastic-ductile-plastic medium of Ishlinskiy type [2], [3], [4] and viscoelastic Voigt medium with the delay of deformation (see Fig. 1). The four-element rheological model of Ishlinskiy most fully reflects the dynamics of plastic deformation and destruction of a solid body in the cut off layer of metal. ...
... The process describing relation of brittle and ductile fracture of material is presented in (Fig. 1). Indeed, we can assume that the brittle fracture corresponds to break of elastic external element H 1 and viscous fracture corresponds to the break of elastic internal element H 2 which is preceded by the relative shift of viscous element N 2 [3]. Elements of mechanical system can be considered in relation to the direction of deformation with the input and output, the direction of the pointer in the ( Fig. 1) indicates the direction of deformation of the system. ...
... With the ultrasonic method, plastic deformation of the surface of the treated metal occurs, which leads to slight hardening at shallow depth. During treatment of the welded joints from carbon and low-alloy steels, this method allows tensile stresses to be transferred to compressive surfaces due to deformation [5][6][7][8][9][10][11][12]. ...
Performance of the tanks depends on the tightness of all their components and joints, quality thereofis formed during the construction phase. Analysis of the results of the VST (vertical steel tank) examination shows that a greater number of defects are concentrated in the chuck unit of the tank - the place where wall and bottom meet. The main issue that arises in the installation of vertical steel tanks is technological lack of penetration of the chuck unit, as well as excess of the clearance in the joint of the welded joint directly prior to welding, due to high threshold deviations in the foundation base dimensions and imperfect assembly operations. Additional tensile stresses resulting from elastic deformation of the bottom to ensure the required clearance in the welding lead to premature failure of the tank. It has been experimentally shown that with increasing clearance in the joint (with subsequent reduction to the rated value), the fatigue life of the chuck unit decreases. Various types of additional treatment allowing one to prolongservice life of the chuck unit.
... where J d is rotor inertia of a motor and other elements (couplings, gears etc) [6][7][8], set on an engine shaft; J 1….n is an inertia moment of parts do not set on the engine shaft; n 1…..n is engine shaft speed, (rpm). Formula (4) presents that ∆ М i J value can also be minimized by decreasing a torsional rigidity of GV. ...
The current scientific and technical problem of ensuring the product quality at the integration of diverse elements (mechanical, electric, operating) into unified technical system (TS) has been considered. The system "electric actuator - gate valve - operating system" (EA-GV-QS) demonstrates the possibility of using the "system properties" to improve the quality and competitiveness of product. We have formulated basic trends of ensuring quality at design of the TS consisting in establishing "system properties", identifying framework factors, defining conditions and restrictions at technical compatibility of diverse elements. Implying the given trends allows to increase the quality level and competitiveness of technical systems by the correct usage of "system properties".
... For this reason, transiency arises in the variability of both kinds of forces because of an elastic force pressing the tool away from the workpiece, bringing about oscillation of the MPS and the emergence of an auto-oscillation process. The fact that the occurrence of self-excited oscillatory processes in a closed system brings about deterioration of workpiece roughness is generally known [1], [6]. Therefore, solving the problem of vibration suppression in a MPS is an important research mission. ...
The paper analyses possible solutions for mathematical modeling in studies of dynamic processes in dynamically self-locking mechanical systems. The research performed is based on the dynamic system with two degrees of freedom conditioned on the system’s inertial and elastic properties. The orthogonal worm gear with equal helix angles is taken as an example. The paper studies two modes of operation: forward movement and reverse movement. The resulting mathematical model allows determining parameters conditioning self-locking properties of mechanical gears.
