Conditions Of Contact Interaction Research Articles

Внутренняя конфликтность личности и ее связь с показателями сформированности профессионального «Я» в структуре индивидуальности у студентов психологических специальностей

Introduction. The article presents the results of an empirical study aimed at identifying the peculiarities of the connection between the severity of internal conflict and a complex of psychological and socio-psychological characteristics of an individual in the structure of individuality as a subject of professional socialization. Theoretical analysis. The analysis of research results in the scientific literature revealed the presence of conflicting data regarding the connection between internal conflict and the productivity of professional activities, including representatives of helping professions. Empirical analysis. Correlation connections have been identified that allow us to draw a conclusion about the role of the severity of an individual’s internal conflict in the formation of professionally significant personal and socio-psychological properties in the structure of individuality, ensuring the success of mastering and implementing professional activities by future psychologists. Conclusion. Internal conflict in future psychologists can be combined with low levels of self-regulation and volitional efforts, difficulties in demonstrating the “Adult” ego-position in conditions of interpersonal interaction, but at the same time, internal conflict does not prevent the manifestation of responsiveness and sincerity in conditions of contact interaction as professionally significant qualities formed in the conditions of professional socialization.

AN IMPROVED ENGINEERING MODEL FOR CALCULATING THE RADIAL STIFFNESS OF ROLLER BEARINGS

The paper presents an analysis of quasi-static models for calculating stiffness and substantiates the choice of the most effective engineering model for calculating the radial stiffness of roller bearings. The analysis of quasi-static models for calculating the stiffness of roller bearings is carried out, which consists in numerical-analytical modeling of force-displacement ratios under conditions of contact interaction. It is noted that for roller bearings, semi-empirical dependencies proposed by Palmgren, Jones and Harris are more often used. For all numerical-analytical quasistatic models of roller bearings, a generalizing relationship between force and displacement at contact is introduced within the framework of the Hertz contact theory, where the stiffness characteristics are determined by the solution of the corresponding contact problem. The numerical values of constants obtained by several authors on the basis of empirical approaches or an approximate solution of the contact Hertz problem for steel bearings are given. In this paper, an analysis of quasi-static models for calculating stiffness is presented and the choice of the most effective engineering model for calculating the radial stiffness constants of roller bearings is substantiated. To solve the contact problem of a separate rolling element and rolling tracks, a finite element periodic model consisting of two halves of the rolling element is used, which are in contact separately with part of the inner and outer bearing rings, respectively, and have physically justified boundary conditions. The labor and computer time required to implement the proposed approach is less than when using the finite element method to determine the stiffness "in the forehead" for each individual bearing, which makes this model an effective engineering model for calculating the stiffness of roller bearings.

Improving shape formation under conditions of plane tensile stress

Thin-walled axisymmetric truncated parts made of sheet billets are actively used in rocket and aerospace engineering. Improvement to their shape formation, based on directed material thickness change will ensure the production of parts with minimum thickness variation. This will also enable aviation and space industry enterprises to attain leading positions, as well as reduce labor costs. This work studies the possibility of obtaining thin-walled axisymmetric parts of truncated tapered shape using one of the methods of sheet metal stamping under flat tensile stress conditions (flanging). The mechanism was identified and the analysis of the stress-strain state of the billet during deformation was carried out. This takes into account the minimizing of the difference between the specified and technologically possible thicknesses. A mathematical model was developed to consider the shaping method based on the process of flanging. Theoretical studies were based on the principles of the plastic deformation theory of sheet materials. This was achieved by the following factors: approximate differential equations of force equilibrium; equations of constraint; plasticity conditions; and fundamental constitutive relations under given initial and boundary conditions. The process of flanging was simulated using the LS-DYNA software package with the following initial data of a conical billet made of 12Kh18N10T steel: cone angle 16.4°, thickness Sbillet = 0.3 mm. The aim was to eliminate errors in designing a tool for future implementation of the method on a manufactured die tooling, as well as to confirm the theoretical conclusions on the selection of technological parameters and achieve minimal thickness variation. The steps of computer modeling are presented, indicating the main process parameters such as material model, mechanical characteristics of the workpiece material, type of elements, kinematic loads, conditions of contact interaction of elements with each other, etc.

Effect of Contact Interaction Conditions on Impact Simulation Results of CFRP Laminate

Finite element based contact impact analysis is an important tool to design composite structures for ballistic impact applications. In the current study, a user-defined material subroutine (VUMAT) that supports 3D solid elements based on Hashin damage criteria for fiber and Puck damage criteria for matrix failure is used for numerical impact analysis. Impact on carbon fiber reinforced laminate (CFRP) of 3.6 mm thickness with [0,90,0]3s stacking configuration is carried out both in Abaqus/Explicit and Ansys/Explicit. The impact simulations are carried out to check the effectiveness of different contact interaction conditions to simulate projectile impact problems. The residual velocities of the projectile from the numerical simulations are compared with experimental results from the literature [1]. The contact interaction condition that gives residual velocities close to experimentally observed residual velocities is evaluated under three initial conditions. The simulations are also carried out in Ansys/Explicit to compare the effectiveness of simulating the same impact problem.

Cutting Process Consideration in Dynamic Models of Machine Tool Spindle Units

Reducing the deviation effect from the specified machining conditions on the quality of the process in real time is the desired result of the intelligent spindle control system. To implement such a control system, a dynamic interaction model of the technological machining system with the cutting process was developed. The transfer matrix method of a multibody system was used in the development of the dynamic model. The physical closure condition of the technological machining system for using the transient matrix method is implemented in the developed model by introducing into this model an additional elastic coupling of the contact between the tool and the machined workpiece. The model is presented as a dynamic model of the elastic system “spindle unit–workpiece/tool–cutting process–tool/workpiece”. To develop the dynamic model, the system decomposition was performed with an analytical description of the joint deformation conditions of the subsystems and the use of the transient matrix method to calculate the harmonic influence coefficients of these subsystems. The proposed approach is used to calculate the native vibration frequencies of the spindle with the workpiece fixed in the chuck and supported with the tool. The calculation results correspond to the experimental ones and quite accurately represent their trends for different contact interaction conditions.

Результаты расчетов напряженно-деформированного состояния и устойчивости грунтовой перемычки сухого дока с учетом ее перепрофилирования

The purpose of the work was to determine the stress-strain state, to check the bearing capacity of structures (sheet pile walls, anchor rods) and the overall stability of soil prisms of the «structure-enclosing soil mass» system, taking into account its re-profi ling. According to the scope of work, computational study of the sheet pile wall structure of the excavation under the buttress foundation was performed (specifying the adequacy of the solutions adopted in the drawings for the length and spacing of the tie rods and the bottom marks of the sheet pile walls by section, as well as the struts in the west abutment and the need for geotechnical anchors. The computational studies were carried out with the PLAXIS software package. In the fi nite-element model there were realized: conditions of contact interaction of media; nonlinear and plastic properties of materials; geometrical nonlinearity in the form of staggered erection and sequence of loadings application.

A universal algorithm for linear and quadratic programming in the problems of contact deformation of cable-stayed structures with one-way connections

Problems in production activities that require optimization problems are extremely numerous and very diverse. Optimization approaches are most often associated with the search for the best version of a structure or building. Mathematical methods for solving such problems are developing rapidly and are widely used. They actively and productively penetrate into many areas of scientific research, into engineering and design developments, are an important tool for improving design efficiency throughout the entire process of creating structures. The search for the best design solution is reduced to the selection of a set of parameters that provide a stationary value of the objective function. A wide range of extreme problems of practical orientation, as a rule, in mathematical models contains restrictions on design parameters of the equality-inequality type. In general, their set makes up the content of such a section of mathematics as Mathematical Programming. Due to the fact that there is no single solution method, diversity in research approaches has formed, which divides them into groups, classes, etc. Linear programming (LP), as one of the sections, with a linear objective function and constraints is well studied and successfully applied. Methods of solving problems of nonlinear programming, which includes quadratic programming, are more complex. Therefore, the development of convenient computational schemes is relevant. The essence of this work is that the statements of 2 optimization problems are formalized in a single and convenient form of a symmetric matrix dependence, which makes it possible to obtain an effective (in our opinion) algorithm for their implementation. Namely, a unified scheme for solving both LP and KP problems based on matrix algebra operations is proposed. Quadratic programming (QP), as the second section, also has wide possibilities, in particular, it allows considering the practical tasks of calculating VAT in the mechanics of a deformed solid body under the conditions of contact interaction. Such problems, in particular, include cable-stayed structures with one-way connections and span lengths that can reach tens or hundreds of meters. As an example, the behavior of a model cable-stayed span structure under varying wind loads is considered. The given results may be of interest.

THEORETICAL BASIS FOR THE ANALYSIS OF CONTACT INTERACTION AND ELASTIC-PLASTIC DEFORMATION OF ELEMENTS OF CIVIL AND MILITARY PURPOSE VEHICLES

The problem that is solved and described in the article is the need to synthesize new technical solutions for the elements of military equipment. To this end, scientific principles have been developed and implemented, mathematical and numerical models for the study of the stress-strain state of bodies made of modern materials in the conditions of contact interaction and elastic-plastic deformation have been improved. A fundamental feature is the use of microstructural models of the properties of materials in volume and on the surface. In addition, at the macro-scale level, a more general variational statement has been developed that takes into account physical and structural nonlinearities. This gives significantly higher opportunities in substantiating better technical solutions of elements of military equipment with tactical and technical and technical characteristics at the world level by conducting studies of the stress-strain state of contacting bodies. A variational formulation based on a modified Kalker principle has been developed for this purpose. The problem is stated with respect to the increments of the contact pressure. The discretization is performed by means of the boundary element method. Besides, another formulation via variational inequalities is developed. In this case the contact problem is stated for thedisplacement increments of the surface points of the two bodies. Correspondingly, discretization is performed by means of the finite element method. The resolving system of equations and inequalities is ultimately derived in the general form. The analysis of the stress-strain state of the contacting bodies with account for their elasto-plastic deformations is hence performed in the most general form. This problem statement forms a basis for the analysis and justification of design solutions for machine elements by strength criteria. Keywords: : military and civilian vehicles; stress-strain state; contact; tactical and technical characteristics

Study of the limiting parameters of deep drawing of sheet blanks made of heat-resistant copper alloys

This article studies the mechanism of thin-walled workpiece deep drawing in the mould with a conical die and determines the forming limit state that occurs at the time of the bottom detachment in the radius part of the punch when stresses in the meridional direction reach their maximum value. This condition is determined by a decrease in the workpiece edge size at the stage of slow material hardening and a decrease in the workpiece flange area that are main factors hindering the process. This condition makes it possible to establish a criterion used to determine the limiting drawing ratio (ratio of the diameter of the workpiece to the diameter of the part), namely: equality of meridional stresses in the punch radius rounding area and the material tensile strength. The paper establishes the effect of the workpiece material strength properties, friction and die taper on the limiting drawing ratio. A change in the plastic and strength properties of the BrKh08 heat-resistant copper alloy (tensile strength, yield strength) does not affect the material hardening constant values and practically does not affect the limiting drawing ratio. The paper uses a comprehensive research method including theoretical analysis and modeling in the ANSYS/LS-DYNA software with input data for the 1.35 mm thick workpiece 100 mm in diameter made of BrKh08. The article presents computer simulation stages indicating main process parameters such as the workpiece material model, mechanical properties, type of elements, kinematic loads, conditions of contact interaction between elements, etc. Process simulation results confirmed theoretical conclusions necessary for the process implementation without part defects.

DETERMINATION OF THE COEFFICIENT SLIDING FRICTION VALUE IN THE CONTACT THE CUTTING TOOL-COMPOSITE

One of the most important characteristics in calculating the cutting tool wear in contact with the processed composite is the friction coefficient. In most calculations, including the finite element method, the friction coefficient is traditionally set as a constant, the value of which is often taken from experience without any reason. However, when machining reinforced composites, there are too many mechanical and technological factors that have a very strong effect on the friction coefficient value. This influence is associated not only with the initial heterogeneity of the composite, but also with the constant actual change in the contact conditions over time, caused by the wear of the tool cutting part. The friction coefficient value in real conditions of contact interaction has a very complex physical content due to the presence of products of fibers and binder destruction in the contact, partial a binder melting at a temperature in contact, and the unevenness of the cut fibers presence.
 This article presents a formulation that allows you to calculate the value of the friction coefficient depending on the volumetric content and the inclination angle of the reinforcing elements. It is proposed to calculate the friction coefficient value as the product of two factors, one of which is responsible for the filler volumetric content, and the other for the reinforcing elements orientation. The calculations use the mixtures theory relations .The presented expressions for calculations are based on the use of limited experimental information presented by various authors. The available data are often contradictory and relate, as a rule, to predicting the processed surface quality of unidirectional glass and carbon fiber reinforced plastics. At the same time, the friction coefficient value in the calculations has a significant impact on the representation of tool wear and life. The model does not take into account the contact pressure effect, mutual sliding velocity and temperature on the friction coefficient value, which will be the subject of further research in this direction.

Прогнозування параметрів вивалоутворення в очисних вибоях глибоких вугільних шахт

Purpose. Process research of the parameters of the cave-in rock formation in roof of the 9th northern longwall of block #10 “Mines Control Pokrovske” Method. Numerical modeling of the volumetric stress-strain state (finite element method), the method of continuous media, the method of contact interaction of surfaces, analytical studies of the process of the formation of rock cave-in of the immediate roof. Results. The article presents the results of numerical modeling of the three-dimensional stress-strain state of a layered rock massif, with boundary conditions of contact interaction between rock layers and with the load of gravitational forces. The results of the grapho-analytical method of modeling the volume formation of fallout formation are presented on the example of working out the 9th northern bench of block No. 10 “PRAT Mine Management Pokrovske”. Calculated collapse parameters of the direct and main roof. The obtained parameters of fallout and their location. Scientific novelty The results of predicting the formation of cave-in rock the immediate roof of cleaning potholes using the volumetric stress-deformed state of a layered massif with the gravitational load of rock layers are presented. The results of predicting the formation of cave-in rock using the rock crack resistance criterion are presented. Practical significance. The practical significance lies in the method of predicting the processes of cave-in rock formation in the immediate roof during the working of coal seams and determining their parameters. The calculation process of numerical modeling of the step-by-step increase of the produced space gives a general picture of the state of rock layers above the produced space and their destruction zones, and determines the following measures to strengthen the roof in the coal face.

РАЗРАБОТКА КОНСТРУКЦИИ ДЛЯ КОНТРОЛЯ ВДУВАЕМОЙ МАССЫ СМАЗОЧНО-ДЕЗОКСИДИРУЮЩЕГО МАТЕРИАЛА

The most important task of increasing pipe production efficiency is the task of improving the quality of manufactured products. Further development and improvement of pipe manufacturing technology is connected with studying the conditions of contact interaction in the pair “tool – deformed metal”, in particular with creation of separating layer. Application of modern lubricant-deoxidizing materials (hereinafter deoxidant) and modern equipment for their application allows to achieve guaranteed separation of contact surfaces. Also creating of separating layer provides significant advantage in terms of improving the quality of finished tubes, operational reliability of finished products, reducing the cost of production and intensification of deformation processes. However, the uneven distribution of the deoxidant on the inner surface of the sleeve leads to a decrease in the quality of the inner surface of the finished tube, as well as to the uneven wear of the mandrels of continuous mills. One of the reasons for lack of guaranteed separation of contact surfaces is mismatch of blown out portion of deoxidant with the set value. The article describes the principle of operation of standard cyclones and calculates the standard cyclone design. The results of computer simulation of a cyclone of standard design and a modernized cyclone are presented. Also presented the results of physical experiments on particle capture.

ОБҐРУНТУВАННЯ СПОСОБУ ПРОГНОЗУ ВИВАЛОУТВОРЕННЯ ПОРІД ПОКРІВЛІ НАД ОЧИСНИМ ВИБОЄМ

Purpose. Justification of parameters and development of the method of forecasting the formation of roof rocks over the coal face. Methodology. Numerical modeling of the volumetric stress-strain state (finite element method), the method of continuous media, the method of contact interaction of surfaces, analytical studies of the process of rock cave-in formation of the roof rocks. Results. The article presents the methodology and results of numerical modelling of the volumetric stress-strain state of a layered rock massif, with boundary conditions of contact interaction between rock layers and with the load of gravitational forces. It has been established that the process of formation of a bulge in the zone of support pressure begins with the formation of intersecting systems of cracks, the direction of which depends on the angle of inclination of the plane of destruction. For the prediction of rock cave-in formation, the criterion of crack resistance of rocks under mixed loading of a through crack has been substantiated. The method has been developed for determining the local zones of formation of cave-in, which allows determining the location of the fallout in the excavated longwall field and its parameters. Scientific novelty. The method of predicting the parameters of the formation of rock cave-in has been presented for the first time, taking into account the criterion of crack resistance of rocks under mixed loading of a through crack. Practical significance. Practical significance lies in the method of predicting the processes of cave-in rock formation in the roof rocks during the working of coal seams and determining their parameters.

Changing the profile of the working surface of a diamond wheel when grinding high-density Аl<sub>2</sub>О<sub>3</sub>‒TiC -ceramics

As a result of studying the nature of changes in the profile of diamond wheel working surface during grinding of high-density Al 2 O 3 ‒TiC ceramics, the main mechanisms of destruction of diamond grains and formation of layer of sludge on the grains and the bond are established. The influence of factors of changing the profile of the diamond wheel working surface on contact interaction conditions during grinding and reducing its cutting ability is estimated.

Моделирование дискретных контактов термодинамической системы элементов сборной дереворежущей фрезы

Operational capability of a modular wood-cutting tool depends, besides many factors, on the design features of cutting element fastening unit. There are no clear and precise methods that explain major factors influencing tool durability for selecting the design of the modular wood-cutting tool, which would meet production requirements. Thermodynamics modeling under contact interaction of elements enables to choose a design for effective application and increases the tool efficient life. The research purpose is modeling of thermodynamic processes in the cutter element fastening unit in the wood-cutting tool body in order to optimize the design, technological parameters and operating modes of the tool. The research subject is the contact interaction conditions and heat transfer processes between the device elements. The cutting element fastening unit is designed and the model of interaction between the parts of the mechanism of the modular wood-milling tool is developed. Further tasks, namely, development of a model of thermodynamic processes in the cutting element fastening unit, discussion of the results and identifying the recommendations for choosing the design of the modular wood-cutting tool at the design stage were realized in a work that continues the ongoing research. The finite-element model of rough wavy surfaces contact interaction of design elements was developed on the basis of standard design of a shell-type plain woodmilling cutter. The analysis concluded that further analytical modeling of contact conditions with existing parameters is possible. The contacting surfaces approach and the radii of single contact areas were determined taking into account the data of design and calculation of wood cutting forces. These results will be used next in modeling of thermodynamic processes. Methodology and research methods comprise theoretical study and mathematical modeling, including finite-element analysis. The models developed are possible to be used in the creation of a complex durability model of the wood-cutting tool with regard to other factors. The main result of this research stage is obtaining the model of contact conditions and initial data for further modeling of thermodynamic processes in the knife fastening unit in the milling body to predict its thermal condition.

Numerical Study of Stress-Strain State of Workpiece in Contact Problem of Surface Mandrel Drilling

In recent years, the economic factor has played an increasingly important role in the selection of technologies for manufacturing machine parts with specified values of normalized parameters of geometric accuracy and quality of working surfaces. As applied to surface plastic deformation processes, this is noticeably manifested in the search for effective friction control methods in the “tool – workpiece” pair, which ultimately determines the distribution pattern and the magnitude of stresses and strains in the workpiece and the tool. It is not possible to obtain a rigorous analytical solution to the problem of establishing a connection between surface conditions, friction, and the stress-strain state of the contacted bodies. In this regard, the construction of mathematical models comes to the fore, the solution of which is possible by numerical methods. The paper presents the results of a numerical study (computational experiment) of a finite-element model of workpiece deformation under various conditions of contact interaction and friction by one of the methods of surface plastic deformation – surface mandrel drilling. The friction coefficient has been chosen as the criterion for assessing the conditions of contact interaction and friction. It is shown that a change in the friction coefficient in the process of surface mandrel has no noticeable effect on the formation of a stress field in the deformable workpiece both in the axial, and in the radial and circumferential directions. At the same time, with an increase in the value of the friction coefficient in the “tool – workpiece” pair and with the associated increase in the force of mechanical resistance to deformation of the workpiece, their growth is observed. A computational experiment has confirmed the presence of non-contact deformations of the workpiece and tool during surface mandrel drilling, as well as as a decrease in the value of residual deformations in the workpiece with a decrease in the coefficient of friction. Balance assessment of contact surface displacements in the workpiece (the inner surface of the hole to be machined) and the tool (mandrel) has shown that the deformations of the tool in the elastic region can lead to a significant decrease in the real tightness of surface mandrel drilling.

Selection of interlocking side mills based on modeling thermodynamic processes during cutting. Part 1. Modeling the conditions of contact interaction

The results of research on improving the design of wood-cutting mills are presented. A model of interaction of elements of an assembled cutting tool has been developed to select its structure at the design stage. Initial data and conditions of contact interaction are obtained for modeling thermodynamic processes in the knife attachment unit. Keywords: easy-to-work material, wood-cutting interlocking side mill, attachment point, cutting element, conditions of contact interaction. n.a.kapustina@inbox.ru

ИССЛЕДОВАНИЕ ПЕРЕХОДНОГО ПРОЦЕССАЭКСПЛУАТАЦИИ ПРИ КОНТАКТНОМ ВЗАИМОДЕЙСТВИИ БАРАБАННОЙ ПЕЧИ И ОПОРНЫХ РОЛИКОВ В ANSYSMECHANICAL

At first glance, a rotary kiln is a simple structural object, which is very widespread in the industry of processing and obtaining materials, both for construction and for other purposes. However, behind the external simplicity, there are complex chemical processes, mechanical, subtleties of the control system, the technology of manufacturing large-sized parts that are part of the general assembly and directly issues related to the design and modernization stage. The study of various regularities of mechanical processes associated with the theory of elasticity, kinematics and contact interactions is difficult even separately, especially when the processes run together. Studying the contact interaction of the kiln with roller supports allows to see the anomalous effects that can occur if the design is incorrect. In a specific case, it is necessary to observe how, under the action of external forces, time-varying deformations, displacements, of individual structural elements occur, which are of key functional importance in the operation of the equipment, in conditions of contact interaction of its individual parts, taking into account inertial loads and damping. The study of transition processes with changing force factors in time will allow to obtain the response of the structure to external influences

On self-synchronization of inertial vibration exciters in a vibroimpact three-mass system

The dynamics of a vibration machine’s model in the form of a vibroimpact three-mass system with one shock pair, which oscillations are excited by two non-ideal inertial vibration exciters, is considered. The collision of the shock pair elements is modeled on the basis of the classical impact theory. A numerical simulation of the model dynamics at varying the excitation frequency, as well as the parameters of the initial gap and the coefficient of restitution, characterizing the conditions of contact interaction of the machine’s working bodies with the processed material, has been carried out. The influence of these parameters values on the frequency range of stable synchronization of vibration exciters and stable periodic vibroimpact modes of the system motion has been established. It is shown that at the same excitation frequency, a change in these parameters can lead to a change in the periodicity of the vibroimpact mode and the working bodies’ oscillations mode from synchronous-antiphase to practically synchronous-inphase.

Research of physically modified antifriction-wear-resistant composite polymer materials and coatings on their basis for machine-building purpose

The article presents the results of studies of the tribotechnical properties of composite thermosetting polymeric materials based on an epoxy compound and ultrasonicated oligomeric fillers operating under conditions of contact interaction with a pulp using the example of raw cotton. Regularities of changes in tribotechnical properties (coefficient of friction, intensity of wear) of composite thermosetting epoxy polymeric materials associated with their filling with organomineral fillers and ultrasonic treatment, in contact with raw cotton have been revealed. The temperature and the magnitude of the electrostatic charge arising in the friction zone of rubbing polymer- cotton and composite-cotton pairs on the type and content of organic-mineral fillers were studied.