Abstract Antifriction properties have been studied for a diamond-like coating (DLC) and titanium nitride, used as an intermediate layer to improve adhesion. The physical and mechanical properties of the coatings have been determined, and the tribotechnical properties thereof have been evaluated in an inactive lubricating medium, as well as in lubricating media with surfactant and chemically-active

Abstract The results of studies on the friction coefficient in steel, bronze, and cast iron friction pairs under the conditions of lubrication are presented. Comparative testing of the tribotechnical properties of motor oil without and with the addition of a specialized additive using a UMT-1 universal friction machine has been performed. The analysis of the results has demonstrated a narrow efficiency

Abstract This article describes an approach to evaluating the resource of automatic coupler bodies against the criteria of the metalwork strain damage rate. The results of this study are used to analyze the resource life of an automatic coupler body, including determination of its safe operation life.

Abstract In this paper, we propose a new formulation of the physical reliability principle and build a reliability model in the form of a system of differential equations taking into account variable loads. A load is applied to the input of the dynamic system, and a probability function of failure-free operation is formed at its output. The conditions for the equivalence of dynamic models are studied

Abstract The results of calculated–experimental and numerical studies of the relative strain intensity factors in the case of semi-elliptical inclined surface cracks in the weld joints of 12Kh18N10T austenite stainless steels with the assumption of redistribution of strain and initial residual stresses under nonlinear boundary loading conditions are presented. A parametric equation for the determination

Abstract A mathematical model of the vibrations of an elastic tube bundle in a crossflow is considered. The model is applicable to predict the reaction of the tube bundle components under the action of the vortex and hydroelastic excitation mechanisms considering the intermediate supports placed with gaps between them and the tube components—the presence of the gaps is a necessary precondition for

Abstract— Experimental and theoretical results demonstrating that the fractal nature of a surface periphery destroyed under the impact of dynamic loading can be attributed to velocity dispersion of particles (elementary deformation carriers) at various scale and structure levels of deformation and fracture are presented.

Abstract In this paper, we consider the computational prediction problem of the reliability of mechanical systems that are in operation under irregular loads, which is relevant for modern mechanical engineering. The calculation problems include determining the functioning reliability of such systems as the probability that the parameters (linear and angular displacements, accelerations of the mass

Abstract The results of a numerical study of the thermal and acoustic energies released during the collapse of a single spherical cavitation bubble in water at a pressure of 10 bar and a temperature of 20°С are given. In the model used, we take into account the thermal conductivity of the vapor in the bubble and the surrounding liquid, heat transfer, evaporation/condensation on the surface of the bubble

Abstract The application of the obtained control of multidimensional objects can be suboptimal under conditions of input coordinate uncertainty and can entail unacceptable process quality losses. To solve this problem, a suboptimal control searching method is proposed, which consists in building a control matrix from the input coordinate values, control actions, and control criteria, the distance between

Abstract This work aims at the problem of justification of the tensile strength test of flat glass- and carbon-fiber-reinforced plastic samples. Any technique of sample holding causes a concentration of stress and influences negatively on the strength; quantitative estimates of this effect are presented in this work. Based on a simplified equation of shear analysis, the stress distributions in the

Abstract Parallel manipulation mechanisms are multiloop systems in which the parallel arrangement of the kinematic chains allows for the load capacity to be increased, the size and weight of every component to be reduced, and the movable links to be relieved of the gravity force of the actuators by locating them on a fixed base. In this article, the synthesis of a new parallel mechanism with an increased

Abstract In this paper, we propose a numerical-analytical method for calculating forced oscillations of a shell structure composed of a set of finite elastic cylindrical shells and elastic rings, to which discrete disturbing forces are applied. Examples of calculating the amplitude–frequency characteristics and vibration modes of the shell structure are given.

Abstract This article proposes a technique for coordinating the movements of operating links of two-armed robotic systems with six degrees of freedom. The technique is based on introducing relative positioning matrices for the output links of the mechanical arms and solving reverse problems of the relative manipulator positioning. Manipulators with three degrees of freedom are viewed as mechanical

Abstract This paper presents an experimental study of water filtering through a porous medium exposed to waves generated by a hydrodynamic oscillator. The amplitude–frequency characteristics of the oscillator are obtained for various water flow rates through this oscillator. The optimum flow rate at which the filtration rate is the highest was obtained. These results can be used in the design of hydrodynamic

Abstract We present the results of experimental and computational study of the process of flexure of pipes with complex spatial shapes on a pipe-bending machine using the QForm VX program based on the finite element method. The possibility of predicting the accuracy parameters of the semi-finished product and possible defects by the method of process simulation is shown.

Abstract In this paper, we develop a numerical model that allows predicting the effect of laser shock processing of materials on the occurrence of new cracks, as well as on the propagation pattern of existing cracks. Linear cracks and so-called V-shaped cracks are studied. The fields of residual stresses arising during laser shock processing are determined. The optimal modes of laser shock processing

Abstract In this paper, we discuss the dynamics of a newly developed mobile robot with a vertical movement mechanism on magnetic caterpillar movers. Based on analysis of the current solutions in the field of vertical movement robots, an original kinematic scheme of the movement of the vertical movement mechanism that allows implementing a number of critical advantages compared to current schemes was

Abstract We consider computation and selection problems in reduced models for the study of the dynamical load of the stand of the bridge of a tube-reducing machine. We design and analyze the computational scheme and obtain a system of differential equations for investigation of the dynamic processes in the drive. We provide the order of the computation of the dynamic loading, present relations for

Abstract The results of studying self-braking planetary gears with single-crown satellites, as well as central and ring gears with extra-pole engagement, are outlined. The conditions of self-braking of these planetary gears are determined using the method developed for studying self-braking. The domains of existence of self-braking gearings with the highest performance are found.

Abstract— An approach to solving the problem of image analysis of complexly formalized materials structures of critical parts is considered. Methodological foundations for the automation of the study of the structure of a material, which provides an assessment of the specified operational properties of parts based on the controlled creation of functional systems, are proposed. Methods to estimate the

Abstract In this article we study the theoretical problem of vibrational transportation of bodies along a surface in the state of non-translational, in particular, rotational oscillations. Nonlinear differential equations of motion of bodies on such surface are obtained. It is shown that, in the case where the influence of centrifugal and Coriolis inertia forces can be neglected, when finding the local

Abstract The frequency responses of four experimental shafts in a generation roll over a comparatively stiff stator are presented. The initial conditions of existence and stability of the generation roll in the isotropic rotor–stator system are empirically determined. These conditions are reduced to rotation with a rotation speed near the first eigenfrequency on bearings and to friction with a sliding

Abstract This study presents the method of forming an exact self-similar solution to the problem of hydrodynamic computation of a wedge-shaped support (slider, guide), which operates in the presence of a lubricant, a fusible metal coating on the surface of the guide, and a porous material on the surface of the slider taking the dependence of the viscosity of the lubricant and the permeability of porous

Abstract— It is shown that a multiparameter system of strength, resource, survivability, and safety assessment applies to measuring parameters such as the static, dynamic, and cyclical strength, cracking resistance, cold resistance, and corrosion resistance. The laws of straining and fracture are used, and the general statement and solutions of basic and applied strength, resource, survivability, and

Abstract An algorithm implementing the vector approximation of values for the stiffness matrix of a finite element in the curvilinear coordinate system for a shell of revolution is presented. The algorithm is based on the Timoshenko hypothesis about the inclination of the normal to the middle surface of the shell.

Abstract— This paper considers our experience in applying the structural technique to evaluating the reliability of a therapeutic robotic set designed for guided radiation exposure of malignant tumors in patients. The features of the structural decomposition of the electromechanical systems of the gamma unit and treatment table are distinguished. The results of applying the Relex software set in drawing

Abstract—A device based on smart alloys has been designed for use in machine building items, in particular, in nuclear engineering, for preventing anthropogenic and natural emergencies. The device breaks the electric circuit by cutting the electric wire bundle in case of an emergency increase in temperature above the permissible limit.

AbstractThe kinematics of the motion of floating elements (ring) of rotor mechanisms under steady state rotation modes is examined experimentally. The ring is placed with a gap with respect to the drive cylindrical link and touches it without losing contact. It is shown that the ring motion is a direct asynchronous precession and its points circumscribe epitrochoids, if the driving motion is “lunar

AbstractThe effusion of gas through a small rectangular opening into a vacuum is studied using methods of mathematical modeling. The distribution functions of gas particles flowing out of an opening and the moments of these functions, i.e., fields of gas particle concentrations and velocities, are obtained. The dependence of effusion on the volume from which the gas escapes is investigated.

AbstractThe use of mechatronic rotary linear modules in manipulators of machine-tool equipment is considered. A solution to the inverse position problem is presented, and the kinematic capabilities of a device based on mechatronic rotary linear modules for machine-tool equipment are evaluated. Dynamic equations have been derived used to evaluate the dynamic characteristics and the precision of the

AbstractIn this paper, we consider the problem of calculating the parameters of damped oscillations under the collision of two systems with one degree of freedom. Such oscillations can be accompanied by vibroshock processes with repeated collisions (modes with bounce). The nature of these processes depends on the accepted models of energy dissipation and the design features of the colliding objects

AbstractThe problem of calculating the reliability and fatigue life of machine parts by the fatigue failure under random changes in the actual and limit stresses is considered. According to the corrected theory of the linear summation of damage, a transcendental equation has been obtained that relates the number of cycles until failure to the random loading parameters and the ultimate strength. From

AbstractAn analytical solution to the direct boundary-value problem and the two-dimensional problem concerning the stressed condition in the median surface of a step-shaped shaft is presented. In the boundary-value problem, a singular integral equation with the Cauchy kernel is used, the solution of which can be found in the form of an unlimited increase in stresses at the ends of the integration interval

AbstractIn this paper, analysis of influence of residual stresses in the surface layer of cylindrical friction pairs on the operational wear resistance index is carried out. Stresses of the first kind after application of combined machining are investigated. Combined machining is consecutive electromechanical machining and diamond burnishing. A formula for calculation of residual stresses originating

AbstractThe reliability of complex engineering objects is affected not only by the duration of the failure-free service (the continuous lifetime) but also the number of no-failure actuations to switch on the object into operation or switch it off (the discrete lifetime). The aim of this work is to fill this gap in part.

AbstractThe dynamic characteristics of a saw gin as a subsystem with lumped and distributed parameters are considered in the paper. On the basis of investigation of the machine assembly, graphs are drawn that allow establishing the maximum values of the angle of relative rotation and the angle of rotation of the saw cylinder shaft under torsion.

AbstractIn this paper, the results of full-scale experimental studies on the effect of the structural material strength of thin-walled cases of concentrated explosive charges on the performance of pulsating explosive devices for various purposes are analyzed.

Abstract—A method of design analysis of a magazine ring and wave band springs of unidirectional, high strength, and low modulus fiberglass is represented. The springs are intended as a spring suspension for vehicles and aircraft. The use of split rings with different gaps makes it possible to obtain a nonlinear change in the compliance of suspension. The effects of the creation of equal strength profiling

AbstractAn assessment method for characteristics of low-rate development of fatigue cracks under operational loading is proposed. The method is based on the decrease in the irregular loading level by conservation of its conformity during crack growth. The control factor of the loading decrease is the intrinsic increase in the compliance of a sample during crack growth by its fixed opening. The experimental

AbstractThis article gives a review of three approaches to solving the problems of detecting local rod and pipeline defects and related problems. In the first approach, local defects are modeled by the matching conditions; in the second approach, by delta functions entering into the differential equation; and in the third approach, longitudinal cavities and cracks are modeled by continuous rod sections

AbstractA systematic study of the effect of energy dissipation on critical nonconservative loads within the stability calculation is carried out. Some classical nonconservative elastic stability problems are considered: the stability of a linear form of equilibrium of a double pendulum under the action of a follower force, the stability of a cantilever beam compressed by a follower force (Beck’s problem)

AbstractA numerical-analytical method is proposed for calculating the forced vibrations of a shell structure immersed in liquid. The structure is a set of finite elastic cylindrical shells and elastic rings to which concentrated discrete forces are applied. Examples of a comparative calculation of the frequency response and vibration modes of the shell structure in a vacuum and in liquid are given

AbstractA frictional self-oscillating system with an elastic force delay and external influence is considered while interacting with an energy source of limited power. The procedure for using direct linearization methods to calculate mixed forced oscillations and self-oscillations in a system with delay and limited excitation is described. Based on this procedure, equations of nonstationary and stationary

AbstractThis article presents a method for the analysis of diagnostic acoustic signals for defect detection in composite materials. For this purpose, a multiple-scale decomposition of the acoustic signal and the determination of informational entropy for its components are used. It is established that, in the presence of small defects, the distribution of the power spectral density is little different

AbstractShaping by means of reeling under the conditions of superplasticity using specialized reeling mills is a promising technology for manufacturing axisymmetric parts of gas turbine engines (disks and hollow shafts) based on heat-resistant alloys. Mathematical simulation is an efficient method for determining the energy and thermomechanical parameters of the technological process. This paper describes

AbstractIn this paper, studies aimed to substantiate the directions of improving the reliability of a metal-cutting tool with working parts modified in terms of its service life by application of low-temperature plasma are presented. These investigations employed a database generated by the results of the pilot production operation of a modified hard-alloy tool and the mathematical software developed

AbstractIn this article, the reliability of a gear–motor system is analyzed on the condition that the failure of the gear leads under certain circumstances to the failure of the motor. The states of the system are modeled by a continuous-time Markov chain. The resulting system of differential equations is solved using the Laplace transform. In this way, the probabilities of the system’s states can

AbstractThe effect of combined surface hardening such as electromechanical treatment and surface plastic deformation exerted on inelastic deformation processes occurring in grade 45 steel has been studied. The results of tensile tests and the analysis of the mechanical hysteresis loops for samples of grade 45 steel subjected to combined surface hardening are presented. The characteristic features of

AbstractA methodology for simulating mathematically the limit states of machines and structures subjected to quasi-static operational and shock impacts is generated by considering great (final) deformations and degradation of the properties of materials. The known experimental results and the modern mesomechanics conceptions on the structure, damage, and nonlinear processes of viscous-plastic faults

AbstractA technique is presented for studying two batches of alloys based on Ti and Ni having the shape memory effect, with the help of which the deformation characteristics were obtained for samples of the alloy. Based on the results obtained, the use of alloys with different deformation characteristics for improving the reliability and tightness of pipeline junctions using alloy couplers with the

AbstractThe controlled dynamics of the rotor of an axial pump arranged in conical active magnetic bearings is studied. Bearings of this type make it possible to miniaturize the geometry of the rotor suspension structure, which is an important factor when designing ann auxiliary mechanical blood circulation apparatus. In such facilities, the problem of rotor positioning plays an important role. The

AbstractThis paper presents the results of a numerical study of the liquid heating process during collapse of a single spherical cavitation bubble in water at a liquid pressure of 10 bar, temperature of 20°C, and an initial bubble radius of 500 μm. The simulation of this phenomenon took into account the thermal conductivity of the vapor in the bubble and the surrounding liquid, heat transfer and e

AbstractA phenomenological model describing fatigue damage accumulation by using a tensor measure of the accumulated damage caused by different cyclic stresses is presented for estimating numerically the fatigue life of carbon fibre-reinforced plastics operating under complex stress state conditions. A procedure for calculating the fatigue life by using the presented model is given. An example demonstrating

AbstractThe effect of the technological heredity of the stress–strain state on the accuracy and dimensional stability of nonrigid parts such as shafts is considered. The negative inheritable factors and patterns of inheritance of the stress–strain state of blanks are defined. An improved process of fabrication of nonrigid shafts is presented taking into account the technological heredity.

AbstractThis article investigates the dependence between the method of statistical data processing and the necessary amount of experimental studies required for empirical determination with a given level of reliability of the impact surface dent visual detectability threshold in composite aeronautical structures. Two methods for determining the minimum detectable damage size are considered, one of

AbstractThis article considers aspects of thermomechanical processing at T > 400°C of Ti and Ni alloys with shape memory and the properties of materials with thermal elastic transformations, depending on the thermal and thermomechanical action as well as the aspects of thermal processing of metals with thermoelastic transformations. Technologies are proposed for applying thermal processing to alloy

AbstractThis article examines the aspects of power in-process operations along automatic lines for filling and packaging liquid and half-liquid products. It is shown that individual power station actuators can be replaced with one group air hydraulic actuator without any loss in productivity. Moreover, the dynamics of cutting out ready-made items can be significantly improved. The layout of an air

AbstractFor a reasonable and reliable assessment of durability at the design or operation stage of the tracked vehicles, it is required information about the loading process. For a reliable assessment of loading and, consequently, durability, the question arises about the representative length of the loading process recording. The paper proposes a method for determining the necessary and sufficient

AbstractThis paper presents the results of experimental studies on the process of thermal drilling in workpieces made of barely deformed alloys by the example of the alloy HN62VMYuT-VD. A comparative analysis is presented, and the modes efficient from the standpoint of thermal drill wear and the process productivity are demonstrated. In addition, the revealed geometrical parameters and material of