Rubber-cord Shells Research Articles

Determining the dynamic indicators of the pneumatic spring for high-speed rolling stock in the zone of a rail joint along a railroad track

The object of this study is the pneumatic spring of the high-speed railroad rolling stock that moves over the rail joint of a railroad track with a vertical ledge. The task solved was establishing the dynamic behavior of the rubber cord shell of the pneumatic spring of the high-speed railroad rolling stock, taking into account the design features of the railroad track, namely the rail joint. The methodology for experimental testing of the pneumatic spring of the high-speed railroad rolling stock using the proposed dynamic test installation is given. Experimental tests of the pneumatic spring were carried out within the rail joint of the railroad track, which has a vertical ledge of 7.0 mm. It was established that the maximum value of the accelerations of the rubber cord shell of the pneumatic spring occurs in the vertical plane. The maximum vertical accelerations of the rubber cord shell of the pneumatic spring were 2.4 m/s2, horizontal transverse accelerations – 0.85 m/s2, and horizontal longitudinal accelerations – 0.9 m/s2. It was determined that the deformations of the pneumatic spring in the vertical plane are higher than the deformations in the horizontal plane. The value of the maximum vertical deformations of the pneumatic spring was 4.1 mm, while the maximum value of horizontal deformations was 1.2 mm. The natural frequencies and logarithmic decrements of oscillations damping were determined based on the obtained records of the free oscillations of the rubber cord shell of the pneumatic spring. It was established that the value of the first natural frequency of oscillations of the pneumatic spring is 3.21 Hz. The logarithmic decrement of oscillation damping of the rubber cord shell of the pneumatic spring was determined based on the constructed graph of oscillation damping with an approximating exponent. It is 0.2147. The obtained values of the dynamic indicators of the new pneumatic spring could be used in the future to control changes in the physical and mechanical properties of the rubber cord shell of the pneumatic spring under the operational conditions of the railroad track. In practice, engineers and scientists will be able to take into account the obtained dynamic parameters of the spring when designing and improving the pneumatic spring for high-speed train movement

AN EXPERIMENTAL STUDY OF THE EFFECT OF AN ADDITIONAL TANK ON THE DEFORMATION OF THE PNEUMATIC SPRING OF HIGH-SPEED RAILWAY ROLLING STOCK

The use of a pneumatic spring suspension system in the second stage of spring suspension of high-speed rolling stock is an integral component of ensuring its permissible dynamic indicators and traffic safety indicators. This work is aimed at researching the deformation characteristics of the rubber-cord shell of the pneumatic spring in the vertical and horizontal directions, taking into account manometric pressure, external load and an auxiliary reservoir. To achieve the goal, a methodology for experimental studies of pneumatic spring deformation was developed using a test rig with an assembled pneumatic spring suspension system, power and measuring equipment. Deformations of the rubber-cord sheath were measured by analog sensors of linear displacements using an analog-to-digital converter and special software. It was established that the effect of the auxiliary reservoir on the amount of vertical deformation of the lower part of the rubber-cord shell does not exceed 3.46 %, which allows us to conclude that the auxiliary reservoir of the pneumatic spring suspension system has a negligible effect on the vertical deformations of the lower part of the rubber-cord shell of the pneumatic spring. The dependences of the deformation of the rubber-cord shell of the pneumatic spring in the horizontal direction on the value of the manometric pressure when the auxiliary reservoir is connected and disconnected are obtained. It was established that in the range of manometric pressure changes of 1.0÷2.5 atm the presence or absence of an auxiliary reservoir has little effect on the amount of deformation of the rubber-cord sheath in the horizontal direction. However, at a pressure of more than 2.5 atm, closing the tap to the auxiliary reservoir leads to significantly greater deformation of the rubber cord shell compared to the deformation when the tap is open and the auxiliary reservoir is turned on. The obtained results regarding the deformation characteristics of the rubber-cord shell of the pneumatic spring will allow us to proceed to the study of the dynamic characteristics of the pneumatic spring, which are necessary when establishing safe conditions for the operation of modern high-speed rolling stock at the stage of its design.

Experimental Study of the Regularities of Deformation of the Rubber Cord Shell of a Pneumatic Spring of High-Speed Rolling Stock

Purpose. The aim of this work is to establish the regularities of deformation of the rubber cord shell in the vertical and horizontal directions in the case of changes in the internal pressure in the pneumatic spring by static experimental studies. Methodology. A static test bench was used to establish the regularities of deformation of the rubber cord shell of a pneumatic spring. Changes in the internal pressure in the pneumatic spring were achieved using a compressor, and the deformation of the rubber cord shell was measured directly by high-frequency potentiometric linear displacement sensors. The deformation of the rubber cord shell of a pneumatic spring in both the vertical and horizontal planes was studied under the condition of changing the internal pressure in the spring in the range from 0 to 5 atm. Findings. Using the designed test bench, a methodology for experimental studies of the deformation of a rubber cord shell with increasing internal pressure in a pneumatic spring was developed. The dependences of the deformation value of the rubber cord casing of a pneumatic spring when the internal pressure changes in the range of 0÷5.0 atm were obtained. It is established that the deformation of the rubber cord casing with an increase in the internal pressure in the pneumatic spring in the horizontal plane is more intense compared to the vertical plane. It is found that the maximum values of deformation of the rubber cord shell of a pneumatic spring in the vertical and horizontal directions are observed at the initial stage of air injection in the range of pressure changes from 0 to 0.5 atm. The polynomial equations describing the deformation dependences of the rubber cord shell of a pneumatic spring were obtained. Originality. The regularities of deformation of the rubber cord casing in the vertical and horizontal planes at different values of the internal pressure in the pneumatic spring were determined by experimental static studies. Practical value. The study of the regularities of deformation of the rubber cord shell will contribute to a more accurate modeling of the operation of the pneumatic spring and a reliable determination of its dynamic performance. This will make it possible to use the dynamic performance of the air spring in the spatial mathematical model of the rolling stock at the design stage, as well as to evaluate its dynamic performance and traffic safety indicators.

Investigation of Temperature Fields of Rubber-Cord Shells of Rotation of Connected Couplings of the Drives of Transport Vehicles

Investigation of Temperature Fields of Rubber-Cord Shells of Rotation of Connected Couplings of the Drives of Transport Vehicles

Переходные процессы в активной системе виброизоляции с инерционным компенсатором виброактивных сил

Transient processes were analyzed in the automatic control system of the vibroactive forces electrodynamic compensator. Active vibration isolation system was considered, where a pneumatic spring based on the rubber-cord shell and the vibroactive forces electrodynamic compensator with a hydraulic inertial motion transducer were combined in a single construct. The paper shows that to ensure high efficiency of the vibration isolation, the gain in the electrodynamic compensator control circuit should be sufficiently large, but this leads to an increase in the transient process and the oscillation period duration. The proportional-integral controller could be introduced to reduce the oscillation index in the control system. However, the inertial mass oscillation center is shifting in the electrodynamic compensator in this case, which could lead to losses in its performance. An approach to solving this problem is proposed using the mechanism of averaging the measured current in the control coil and subtracting it from the current value, which makes it possible to eliminate the inertial mass shift while maintaining the transient process short duration, when a proportional-integral controller is included in the control circuit. It is shown that reducing the transient process period due to inclusion of the proportional-integral controller in the control circuit significantly increases the vibration isolation efficiency in the vibroactive forces non-stationary mode, for example, in the start-stop mode.

THE OPTIMAL DESIGN OF THE 40.00-57 DUAL PURPOSE ORTHOTROPIC SHELL UNDER UNCERTAINTY CONDITIONS DESIGN

Problem statement. A feature of the modern technical systems’ design is that deterministic approaches dominate, while consideration of uncertainty can provide a more adequate representation of the research object in the appropriate calculation scheme, mathematical model. The consideration of uncertainties becomes especially relevant in the modeling of complex technical systems, where uncertainties can be quite abundant and the uncertainties themselves can be of different nature, namely stochastic, rough, fuzzy, or even combined. It is advisable to check whether the system is tolerant to uncertainties. This work is devoted to the construction of methods for the optimal design of the new rubber-cord shell 40.00-57 in the conditions of the fuzzy initial data. For a deterministic approach a special mathematical model can be used to calculate the output parameters. The mathematical model developed by Prof. E. Kvasha, at one time was truly revolutionary, because for the first time in the world the contact problem of the interaction of an elastic base with a layered orthotropic shell, which is part of a complex technical tire system, was solved. The main drawback, which could not be overcome by varying the input parameters, remained the uneven resource of the shell frame elements. So, variant design has shown its insufficient efficiency for such complex technical systems. The purpose of the research is to suggest a model and methods of optimal design for optotropic rubber-cord oversized shells under the conditions of real factors of uncertain nature. Conduct methods testing and design a new construction of tire 40.00-57 for civilian and military purposes. Conclusion. The authors proposed models and methods of optimal design of orthotropic rubber-cord shells under the condition of fuzzy data. Approbation of the symbiosis of Monte Carlo methods and the method of local variations for finding the optimal geometry of the shell was conducted. For new 40.00-57 tire shape, the difference between the largest frame resource and the smallest resource of the tire’s elements was about 18 %. Such a result could not be achieved by variant design. The temperature distribution in the cross-section of the tire under conditions of operation for 8 hours at an ambient temperature of 37 0C does not exceed the value of 110 0C, at which the thermal destruction of the rubber-cord material begins.

INFLUENCE OF RIGIDITY OF ELASTIC ELEMENTS OF COUPLING COUPLINGS ON TORSIONAL VIBRATION OF SHUNTING LOCOMOTIVES DRIVES

The results of calculations of torsional vibrations of elements of power drives of shunting locomotives with different torsional rigidity of rubbercord shells of elastic coupling couplings are presented. Based on the results obtained, the choice of rubbercord shells is justified depending on their torsional rigidity. The basis for the choice of shells is the obtained results of calculations of the resonant amplitudes of torsional vibrations by the method of continued fractions.

Determination of the stress-strain state of structures made of viscoelastic fibrous composite materials based on the stiffness matrix of a spatio-temporal finite element

Abstract. Increase in spheres of composite materials application leads to the need to improve the methods of composite structures calculation, increase their efficiency and adequacy to real processes. The use of fibrous composite materials creates difficulties in determining the stress-strain state of the structure due to the different physical and mechanical properties of the material components. As a rule, a fibrous composite consists of two components: a matrix and a fiber. The matrix ensures the material monolithicity fixing the shape of the product and the relative position of the reinforcing fibers. The fibers absorb the main stresses that occur during operation, and provide rigidity and strength of the composite. The combination of the matrix and fiber properties allows creating special types of composites to be used in various equipment. The use of rubber as a matrix gives the structure viscoelastic properties, which can be seen in the deformation creeping and stress relaxation in the material, which complicates the calculation of the stress-strain state of the whole structure greatly. The paper proposes an approach that is the development of a moment scheme of finite elements in the form of the displacements method based on the Lagrange principle. Using this approach, a special space-time finite element has been developed that takes into account the viscoelastic properties of the material matrix and the fiber elastic properties. The proposed numerical approach allows obtaining a solution to the problems of viscoelasticity of composite materials mechanics in three-dimensional model. Using the applications package created on the basis of this approach, the calculation of the stress-strain state of a single-cavity pneumatic cylinder with a rubber cord shell has been done. The influence of the reinforcement scheme and rubber viscoelastic properties on the parameters of the pneumatic cylinder deformation has been analyzed. In particular, it becomes possible to adjust the structure stiffness properties by changing the orientation, type and concentration of fibers, as well as the type of matrix and other material characteristics. Keywords: fibrous composite material, viscoelasticity, space-time finite element.

Development of methods for increasing the performance of rubber cord shells of pneumatic shock absorbers

The article examines the effect of temperature on the change in the characteristics of tribotechnical properties in a pair of friction "rubber-metal". The reasons for the decrease in the efficiency and durability of rubber-cord casings and pneumatic shock absorbers are analyzed.

Damping capacity of rubber"cord shells of rotation, taking into account the nonlinearity coefficients

The results of a study of the nonlinear elastic properties of rubber-cord shells under static loading are presented. A method for determining indicators of nonlinear properties is proposed. The obtained approximations describe satisfactorily the experimental results. Keywords elastic shell, nonlinearity, viscoelasticity, deformation, loading rate, elasticity, hysteresis. a_evdo@mail.ru

Experimental and Calculation Studies into the Possibilities of Improving the Vibration Isolation of Power Installation Pipelines

The article presents the results from studying methods and means for reducing the transfer of vibration and pressure pulsations from power installations through elastic vibration isolators of pipelines carrying liquids (cooling water, condensate, or petroleum products) by suppressing the vibration forces and pulsations of the medium by active suppression systems. The results of studies into this subject carried out within the framework of the agreement between the Russian Scientific Foundation and the Tsiolkovskii Kaluga State University are reported. The article discusses the results from calculation and experimental studies aimed at determining the influence of liquid on the vibration-isolating performance of different kinds of pipeline compensators, including those based on bellows, sleeve-type ones made of rubber cord materials, those based on rubber cord shells, and compensators of a new type containing elastic inserts made using thin-layered rubber-metal elements with the minimal interaction between the structure and working medium. The investigations were carried out with the aim to minimize the transfer of vibration through the compensator by improving its design. The results from experimental studies into the effectiveness of joint suppression of the vibration and pressure pulsations by active methods for reducing the transfer of vibration from power installations to the foundation by means of pipeline compensators are presented. It is shown both analytically and experimentally that there is a frequency band in which the vibration forces transferred through the compensator structure are suppressed by the forces from pressure pulsations. The transfer of vibration becomes a factor of ten or more less than it is in the compensator tested without liquid. A physical explanation for this phenomenon is given, and ways of using it in practice are suggested. A two-channel active vibration protection system with a digital control device containing controllers in the form of standard Butterworth, Chebyshev, and band-pass filters, as well as resonance sections in its feedback circuit, is experimentally studied. With the active joint wide-band suppression of vibration forces and pressure pulsations determining the transfer of vibration through the compensators of pipelines with liquid, the effectiveness was found to be up to 32 dB in the frequency band from 10 to 350 Hz.

Nonlinear Properties of Rubber-Cord Shells of Tire-Type Pneumatic Clutches

Results from a study of the nonlinear elastic properties of rubber-cord shells in a static loading regime are presented. A method of determining the nonlinear properties is proposed. The nonlinearity coefficients are obtained on the basis of a fifth-degree polynomial with odd indicators. The approximations that are obtained satisfactorily describe the results of experiments.

The experimental method for determining the geometric characteristics of pneumatic elements with rubber-cord casing

The method for experimentally constructing the geometric characteristics of pneumatic elements with rubber-cord casing at zero and quasi-zero pressure is proposed. The practical implementation of the method by the example of the rubber-cord shell of the balloon type of model N-50 is illustrated. The processed experimental data in an analytical form presents the empirical dependences of the internal volume on the height of the pneumatic element at zero and quasi-zero overpressure. The obtained parameters are mandatory for the model of air spring and study the damping phenomenon. The results obtained are intended for the development of vibration protection and vibration isolation systems for technical objects, the design of which includes air springs and air damping shock absorbers.

CALCULATION OF THE STRENGTH OF RUBBER-CORD MEMBRANES IN REAL OPERATING CONDITIONS

The article analyzes the existing methods of calculating the strength and torsional vibrations of rubber-cord shells of elastic couplings. The refined estimation of these calculated dependences taking into account physical nonlinearity and thermal fields of elastic shells is made.

Possibilities for calculating rubber-cord shells in modern finite-element analyses packages

As flexible inserts of various designs, including pipeline systems, vibration-insulating pipes are used, which act as compensators to reduce the resulting deformations and vibration loads. The main element of the design of the pipe, perceiving the action of internal overpressure, is a rubber-cord sheath. To study the possibility of calculating rubber-cord shells in modern finite element analysis packages in the present work, the cylindrical shell of the vibration-insulating pipe has been simulated and its stress-strain state in the software package has been calculated. Since the RCS is a composite design, the simulation was carried out using the built into modules. The results obtained make it possible to analysis the composite material of the RCS and to determine the criteria for shell destruction.

Dynamics of anti-vibration mount with quazi-zero stiffness

The paper considers the dynamics of the anti-vabration mount of a new design with the quasi-zero stiffness effect, in which the mounting element is an elastic rubber-cord casing of type I-09, and a load adding element (corrector) is a toroid-shape rubber-cord shell. A mathematical model is developed and motion graphs of vibro-isolated object in the range of 1-10 Hz are built.

SUPPORT FOR VIBRATION ISOLATION OF THE TECHNOLOGICAL EQUIPMENT

Introduction. The most urgent tasks of road construction is to improve the sustainability of the roadway, on which the durability of the road surface largely depends and vibration processes are widely used. Moreover, the mechanization of production processes in construction, the growth of power and speed of technological equipment lead to increasing in dynamic loads on its parts and assemblies. To reduce the dynamic loads in the parts and assemblies of construction machines and equipment, as well as to reduce the negative impact of vibration on the staff, it is necessary to isolate the vibration-generating units and assemblies from the base part of the machine.Materials and methods. The vibro-supports of various designs are used to isolate the vibro-active elements of machines. The authors propose the vibration support design with a quasi-zero stiffness effect, in which the rubber-cord shell of the I-09 type is used as a supporting elastic element, and also the toroid-shaped rubber shell that relies on four identical support segments. In addition, each segment represents the fourth part of the annular tube and cut into two parts by a vertical cylindrical plane. The outer parts of each segment are connected with hinges to the posts and fixed on the support base, and the inner parts of each segment are also connected to a supporting elastic element and a vibration-proof mass is connected by means of hinges. The authors describe the working procedure of the proposed construction and compile the mathematical model of vibration support with a quasi-zero stiffness effect.Results. As a result, the equations of the mathematical model are performed in Matlab with the Simulink extension. The values of the equations are used to plot the strain variation of the toroidal shell of the corrector, which depends on the mass displacement, as well as on the motion patterns of a vibrationproof object of 100 kg for variants of the carrier spring without additional volume and with additional volume of the 1 - 10 Hz pneumatic spring carrier.Discussion and conclusions. The authors determine the pressure in the corrector shell, depending on the isolated object mass. Therefore, the deformation of the corrector shell could be provided with a support structure due to the elasticity of the shell material. The usage of additional volume together with the stiffness corrector allows to obtain a wider area of the load characteristics with quasi-zero stiffness and to improve the vibration-protective properties of the support.

Математическая модель резинокордной оболочки вращения для пневматических амортизаторов

Математическая модель резинокордной оболочки вращения для пневматических амортизаторов

Линеаризованная математическая модель резинокордной оболочки вращения

Линеаризованная математическая модель резинокордной оболочки вращения

Increasing efficiency of vibration protection system by using pneumatic rubber cord devices

The article is devoted to investigation of the vibration protection system based on pneumatic rubber-cord devices. The device and principle of operation of the combined vibration protection system with the use of rubber-cord shells as power elements are presented. The analysis of the developed mathematical model is carried out. New methods of construction and algorithms for controlling the active vibration protection system are investigated on the created experimental complex. The results obtained at the experimental complex are presented and analyzed. The study of the developed mathematical model of combined vibration protection system with throttle control of gas pressure in power cells has shown its efficiency in the low-frequency range. The evaluation of the quality of the combined vibration protection system using integral criteria has shown its effectiveness up to 40% in comparison with the passive vibration protection system with harmonic excitation. The obtained test results have a discrepancy in the low-frequency region of the operating range with mathematical modeling data at the level of 10%.