Advances in Mechanical Engineering

Frontmatter

Mathematical Determination of the Assembly Methods of the RRR Group in the Geometric Analysis of Flat Lever Mechanisms

Abstract

The paper considers issues related to mathematical choice of RRR group assembly method in planar lever mechanisms. A justification for the choice of the sign of trigonometric functions of the relative angle in the structural group is given. The given reasoning allows to unambiguously choose the angle between the links within the RRR dyad.

Pavel A. Andrienko, Vladimir I. Karazin, Denis P. Kozlikin, Andrej V. Khisamov

On the Issue of Dynamics of Program-Controlled Machines

Abstract

The paper considers the basic principles of constructing program-controlled machines. The authors discuss the problem of implementability for program motion and program control. The paper identifies the sources of dynamic errors (influence of initial conditions, inadequacy of the dynamic model of the system, implementability of program motion); it elaborates on the principles of constructing closed-loop control systems with feedback.

Alexander N. Evgrafov, Gennady N. Petrov, Igor O. Khlebosolov, Pavel A. Andrienko

A New Molecular Approach for Creative Design of Multiloop Linkages and Planetary Gear Mechanisms via Novel NTG-Graph Representation

Abstract

This paper presents totality an extended structural mathematical model and technique forming the K-atom molecule as novel graph representation of closed kinematic chain and set of a new universal mobility equations inferred a tool for creation any types of F-DOF planar and spatial mechanisms without injurious redundant constraints. Various examples of creative design the F-DOF self-aligning linkages in form invention and multisatellite planetary gear train are provided and confirms the effectiveness of proposed approach.

Vladimir I. Pozhbelko

Influence of Dynamic Characteristic of Motor on Steady Motion of Machine

Abstract

Technological advances increasingly result in situations when simplest dynamic models with rigid links cannot be used and there is need for more complex models that consider the elasticity of links. This is caused by more intensive technological processes and higher operating speeds of machines, which leads to a growing level of vibrations. The motion equations of a machine unit include the motion equation of the mechanical system and the characteristics of the motor. Ideal motor characteristics can be used at the early stages of machine designing, while a more accurate dynamic analysis requires consideration of the dependencies of the law of motion on the load, reflected by static and dynamic properties. In machine designing it is essential to reduce dynamic errors caused by elastic vibrations of the mechanisms and dynamic properties of the motor in steady-state and transient modes of operation. This problem is particularly important when new high-performance machines and, above all, industrial robots, positioning platforms, etc. are created.

Yuri A. Semenov, Nadezhda S. Semenova

Numerical Simulation of Nonlinear Oscillation Modes of a Three-Link Manipulator

Abstract

The paper deals with the construction of nonlinear oscillation modes of a three-link manipulator operating in the gravity field and having identical parameters of weightless links and end loads, using numerical procedures. A nonlinear mathematical model of oscillations of the system is presented, and as a result of its calculation by means of numerical integration, the specific options for setting initial conditions of motion are determined which are leading to the single-frequency oscillations on the first, second or third nonlinear mode. The main qualitative features and quantitative characteristics of all three nonlinear oscillation modes are noted, and their difference from traditional modes of small oscillations is discussed. In addition, graphical dependencies are constructed which illustrate the change in all key quantities on the period of nonlinear oscillations for each of the nonlinear modes. The obtained results are of interest for analytical mechanics and for theory of nonlinear oscillations, and they can also be useful in solving specific applied problems in the field of robotics and biomechanics.

Alexey S. Smirnov, Serafim A. Bulov, Boris A. Smolnikov

Aircraft Landing on Vane Wheels

Abstract

The paper considers the issues of landing a supermaneuverable aircraft in a strong side wind. It is proposed to install vane wheels into the main landing gear. The results showed the possibility of aligning an aircraft on a runway by means of automatic brake control.

Denis P. Kozlikin, Agata I. Soboleva, Valerii A. Tereshin

Hydrogen Degradation of Material of a Bearing Ring Fitted on a Rotating Shaft

Abstract

The article is devoted to the problem of bearing steel weakening under the negative influence of hydrogen released as a result of the decay of the lubricant during friction. Hydrogen changes the mechanical properties of the metal, affecting the stress-strain state of the shaft and bearing ring, which, in turn, affects the distribution of hydrogen in the system. In this work the stress-strain state of the rotating shaft and the inner ring of the bearing installed with an interference fit is determined. The dependences of mechanical stresses on the radial coordinate are constructed for various values of preliminary interference fit and angular velocity of rotation. The dependences of the diffusion coefficient and hydrogen concentration on the radial coordinate in a stressed shaft-ring system are obtained. It is shown that under the influence of stresses and free hydrogen in the bearing ring, conditions for the degradation of the material are created. The accepted hypothesis about the condition of hydrogen atoms wedging into the crystal lattice of the metal made it possible to carry out a preliminary assessment of the effect of hydrogen on the elastic modulus of the bearing ring material.

Tatiana V. Zinovieva, Aliya R. Galyautdinova

The Reliability Function of Case-Hardened Cylindrical Gears

Abstract

An improved approach to the reliability function calculation of case-hardened spur and helical gears is presented in the paper. The calculation of the reliability function based on six possible gear failures is substantiated: the pitting of a pinion or wheel, the tooth breakage of a pinion or wheel, the tooth flank fracture of a pinion or wheel. The methodology for the reliability function calculation according to the criterion of surface durability (pitting) takes into account the random nature of the misalignment of the teeth in the mesh, caused by the deformation of the gear elements under the action of the transmitted torque (force misalignment). In the given method under the criterion of bending durability (tooth breakage), applied formulas allow calculating an allowable stress number for bending of the tooth through the parameters of the hardened case. Verification of the calculation formulas for the allowable stress number for bending, taking into account the parameters of the hardened case, was carried out according to the experimental data. The calculation methods analysis of deep equivalent stresses is carried out by the authors. The accuracy of the hardness depth profiles (carbonization, carbonitriding) is estimated. The technique has been developed for the reliability function calculation of case-hardened gears according to the criterion of deep equivalent durability. The verification of the developed methods for calculating the reliability function according to the operation data of case-hardened gears is performed.

Sergey Yu. Lebedev, Vladimir N. Syzrantsev

Harmonic Vibrations of the Simplest Shell Models Loaded with a Periodic System of Localised Masses

Abstract

The free harmonic vibrations of two types of simplest shells are studied: Bernoulli-Euler beam on Winkler base and Kirchhoff-Love type shell. The axisymmetric vibrations of the latter are considered. Both shells are loaded by a periodic system of localized masses. The exact analytical solution of these problems in the form of Floquet wave is investigated. On the basis of exact analytical solutions, vibration fields, pass bands (PBs), energy fluxes and its components both in the vicinity of localized masses and outside them are analyzed. The influence of the magnitude of the reduced concentrated masses and relative stiffnesses of Winkler base on the nature of the wave processes is analyzed. The effect of attenuation of the energy flux in the first pass band is investigated. Calculations showing that in some cross-sections of the both models it is possible to zero the work of the shear force on displacements of the shells or to zero the work of the moment on rotations of elementary elements of the shells are given. The vibration fields and components of energy fluxes at the boundaries of the transmission bands are particularly investigated.

George V. Filippenko

Wear-Mechanism Map of Wear-Resistant Steels

Abstract

Tribological tests were carried out on the SMC-2 friction machine according to the “Roller – Abrasive roller” scheme, without lubrication. A simplified map of wear modes of wear-resistant steels (Hardox 550, Hardox 500, Hardox 450) is constructed, compared with structural steel 09Г2C, according to the Lim—Ashby and Williams method. The zones of critical, severe and mild wear are highlighted. Comparative results of steels on mechanical properties, wear, wear intensity and contact temperature are obtained. Metallographic studies of the sample surfaces before and after the tests were carried out. Wear mechanisms are installed.

Alexey Y. Ryabikin, Margarita A. Skotnikova, Galina V. Ivanova

Automated Device for Surface Modification and Synthesis of Functional Layers in Microfluidic Chips

Abstract

The mock-up of an automated device for microfluidic chip surfaces processing by “wet” chemistry methods is presented. Automation of surface modification processes and functional layers creation in microfluidic chip allows to reduce processing time, eliminate the human factor influence, increase reproducibility, accuracy and correctness of subsequent sample analysis of chemical and biological objects. It may be used when creating devices for different purposes, for example, for immune analysis, biochips, for the synthesis of materials and a number of others.

A. L. Bulyanitsa, N. A. Esikova, A. A. Evstrapov

Spring Drives for Downhole Rod Pumps

Abstract

The article discusses the use of spring drives with energy recovery for downhole rod pumps designed for pumping reservoir fluid. The article is devoted to the development of new types of downhole rod pump drives, in particular, spring drives with energy recovery. The use of such spring drives will reduce the dimensions, weight and energy consumption several times. The main idea is to build a spring drive with energy recovery in the form of an oscillatory system. in which the potential energy of the springs is converted into the kinetic energy of the rod, and then the kinetic energy of the rod is converted into the potential energy of the springs. Dissipative losses will be compensated by using various linear motors. The use of a spring drive with energy recovery will significantly reduce its mass, which in turn will allow it to be placed in containers above the wellhead without using a foundation. It is proposed to use such a spring drive with energy recovery both as the main drive and as a balancing device. The article discusses two variants of drives. The first version of a spring drive using balancing with the help of a load. The second option is for synchronous operation of two spring drives that operate in antiphase and provide mutual balancing of the weight of the rods. It is shown that when balancing with the help of a load, the mass of the power springs turns out to be twice as large as in drives operating synchronously. The possibility of using autonomous power supply due to solar panels and wind generators is also shown.

Wen Zhao, V. L. Zhavner, M. V. Zhavner, Sen Li

Horizontal Bump Machine

Abstract

Various types of testing equipment are used for shock testing, including horizontal bump machines. Horizontal machines are most widely used for testing passenger cars and their components, transport pallets with loads, wagon couplers and much more. Unlike vertical shock machines, in which energy is accumulated against the action of gravity, all horizontal machines are equipped with additional actuators for shock. Therefore, an important task in the design of such machines is the choice of actuator parameters and the calculation of actions that ensure the reproduction of acceleration shock pulses of a given shape with the required parameters (peak values and durations). The article considers one of the options for the circuit design of a horizontal bump machine with a pneumatic actuator, developed at St. Petersburg Polytechnic University, and theoretical estimates of the characteristics of reproducible pulses depending on the main design parameters and settings are obtained. These estimates are verified by the results of computer simulation.

A. N. Popov, M. N. Polishchuck, D. V. Reshetov

Greedy Heuristic for Optimized Placement of Orthogonal Polyhedra in Irregular Cutting and Packing Problems

Abstract

The article discusses NP-hard optimization problems of irregular cutting and problems of packing objects of arbitrary geometry. When placing objects, their representation in the form of orthogonal polyhedra is used, obtained after applying voxelization algorithms to given models of objects of complex shape. A greedy heuristic for the placement of two- and three-dimensional orthogonal polyhedra is proposed, which ensures the selecting of the best orientation variant for each object to be placed when searching for the densest placement scheme. The analysis of the effectiveness of the application of this greedy placement heuristic on the problems of flat irregular cutting and packing of three-dimensional objects of non-regular shape is carried out. The application of the proposed greedy heuristic provides fast obtaining if high quality solutions to the problems of packing a large number of objects represented in the form of orthogonal polyhedra. It is shown that the best solutions are obtained as a result of the joint application of the genetic algorithm and the proposed heuristic.

Vladislav A. Chekanin, Alexander V. Chekanin

Theoretical Stress Concentration Factors at a Cruciform Welded Joint

Abstract

The engineering dependencies to calculate the theoretical stress concentration factor at a cruciform welded joint are analyzed. Based on the comparison of the dependences under consideration with the results of studies of cruciform welded joints by the finite element method, formulas that best determine the theoretical stress concentration factor are established.

Konstantin P. Manzhula, Anton Y. Shlepetinskiy

Study of Welded Joint Failure at Negative Temperature

Abstract

An experimental-computational study of the strength of welded samples with a crack-like defect under conditions of negative climatic temperatures has been carried out in the current work. A brittle fracture model of a part with a crack has been presented. A finite element analysis of the stress-strain state of the samples has been performed. It has been presented that the test results do not contradict the fracture model. The model evaluates the lower limit of the strength of the part with a crack-like concentrator.

Sergey Alekseevich Sokolov, Aleksey Andreevich Grachev

Increasing the Efficiency of Drilling Rigs by Using the Blagonravov IVT in the Top Drive System

Abstract

The article deals with the issue of installing a mechanical infinitely variable transmission with an electric drive in the top drive system of drilling rigs. The disadvantages and advantages of the top drives existing design of drilling rigs in electric and hydraulic versions are considered. The results of the external characteristics calculation of the top drive are presented, showing that the use of Blagonravov mechanical infinitely variable transmission as a reduction unit will provide a more complete use of the electric motor power. At the same time, the dimensions of the transmission will not exceed the dimensions of the existing top drives of the corresponding power.

Sergey Ivanovich Hoodorozhkov, Andrey Vladilenovich Yurkevich

Corrugation of Thin-Wall Tube-Blanks at Axial Rotary Forging

Abstract

The paper presents the results of a study of the process of axial rotary forging of internal flanges by flanging from thin-walled tubular blanks with a conical roll. A feature of the process is the possible loss of stability of the blank shape in the form of corrugation, which does not allow obtaining parts of the required geometry. On the basis of computer simulation, the reasons for the loss of stability of blanks during rotary forging are systematized, the kinematic characteristics of the machine and the geometric parameters of the tube-blanks that affect this process are determined.

Leonid B. Aksenov, Nikita M. Potapov, Sergey N. Kunkin

Development Prospects of Dies and Equipment for Elastostatic Pressing of Products from Powders

Abstract

The paper analyzes how the elastostatic pressing technology is used today for making structural parts. It considers the main types of dies that can be useful for quasi-isostatic, radial-axial and radial elastostatic pressing (ESP), and discusses the main types of equipment applied in elastostatic pressing. The paper illustrates the prospects of the method, e.g. designing composite elastic matrices with rigid base elements and creating specialized machines (elastostats) for pressing structural products in sophisticated shapes.

Pavel Alekseevich Kuznetsov, Ruslan Valeryevich Kuznetsov, Kirill Vladimirovich Lepetan

Water Cavitation During Electrohydropulse Stamping

Abstract

The influence of cavitation effects during electrohydropulse stamping is considered. The effect of cavitation in the working fluid on the inner surface of the discharge chamber and its destruction is shown. A one-dimensional model of bubbly liquid has been developed that enables estimating the change in the pressure pulse parameters in presence of a layer of bubbles of different porosity near the chamber wall. The problem was solved by the finite difference method, with a numerical implementation in C++. The correctness of the model was verified by comparison with a test calculation of a similar problem for a homogeneous compressible fluid, modeled in LS-DYNA 971 complex. It is shown that a layer of bubbly liquid makes it possible to almost double the pressure amplitude on the rigid wall of the chamber and removes the reflected shock wave under the conditions of electrohydropulse stamping. The obtained results can become the basis for creating more efficient technological processes and devices for EHS.

Viacheslav S. Mamutov, Alexander V. Mamutov, Xenia S. Arsentyeva, Ivan V. Kalatozishvili

Mathematical Modeling of Coatings Thermal Spraying Kinematics on Complex-Profile Internal Surfaces of Parts

Abstract

The article looks at the main technological problems associated with the deposition and mechanical processing of thermal spray coatings. It is noted the problem urgency of ensuring the thermal spray coatings application uniformity on the complex-profile internal surfaces of parts. A model for estimating the thermal spray coating thickness distribution depending on the sprayed material flow kinematics parameters has been developed. The developed model is based on normal and uniform distributions density functions properties. The mathematical model was verified using four thermal spraying kinematic modes combinations variants.

Artem A. Kovalev, Nikolay V. Rogov

Application of the Thermofluctuation Theory of Strength to Calculate the Durability of Adhesive Joints in the Case of Granite-Bitumen Composites

Abstract

The article considers the adhesive and cohesive mechanism of polymer composites fracture, including method for determination of strength and durability parameters, as well as their dependence on temperature-time factors. The results of experiments performed with granite and bitumen compounds, including those modified with red iron oxide (Fe₂O₃), are presented.

Andrey Ivanovich Rudskoy, Albert Yakovlevich Bashkarev, Victoria Yurievna Bessonova

Forecasting the Mechanical and Processing Properties of a Near β-Titanium Alloy

Abstract

This article reviews the problems of forecasting the mechanical and processing properties during the cold deformation of the near-β-titanium alloy VT35 depending on its chemical composition. Having analyzed the available publication and signature research, the authors established that the fluctuations of the rated composition result in significant variations of properties. They established that the strength of the VT35 alloy is mainly defined by the α-stabilizers of aluminum and interstitial impurities, while the increase in the total content of the β-stabilizers results in a slight reduction of the strength limit. The authors developed the requirements that can help increase the processing properties of the VT35 alloy during cold deformation.

Yu. B. Egorova, L. V. Davydenko, E. N. Egorov, S. B. Belova

Improving of the Electrohydroimpulse Installations Efficiency for Clearing Castings

Abstract

This paper focuses on the basic design of the experimental electrohydroimpulse plant for crushing materials and cleaning castings from the core mass. The design and operating parameters affecting the effective contribution of energy during a high-voltage discharge in a liquid are also discussed. It is predicted that the provision of “hard” processing modes is possible by changing the parameters of the discharge circuit of the installations. Special adjustment of the traditional electrical circuit and a joint arrangement of technological and energy blocks with the use of modern switching devices have been provided.

Valeriy P. Tretyakov, Alexandra O. Prostorova, Vasiliy G. Teplukhin

Backmatter