scholarly journals Determination of dynamic loading of bearing structures of freight wagons with actual dimensions

2021 ◽  
Vol 2 (7 (110)) ◽  
pp. 6-14
Author(s):  
Oleksij Fomin ◽  
Alyona Lovska
Keyword(s):  
Service Life ◽  
Dynamic Loading ◽  
Software Package ◽  
Equations Of Motion ◽  
Operating Conditions ◽  
Vertical Acceleration ◽  
Vertical Loading ◽  
Bearing Structure ◽  
Freight Wagons

The determination of the dynamic loading of the bearing structures of the main types of freight wagons with the actual dimensions under the main operating conditions is carried out. The inertial coefficients of the bearing structures of the wagons are determined by constructing their spatial models in the SolidWorks software package. Two cases of loading of the bearing structures of the wagons – in the vertical and longitudinal planes – have been taken into account. The studies were carried out in a flat coordinate system. When modeling the vertical loading of the bearing structures of wagons, it was taken into account that they move in the empty state with butt unevenness of the elastic-viscous track. The bearing structures of the wagons are supported by bogies of models 18-100. The solution of differential equations of motion was carried out by the Runge-Kutta method in the MathCad software package. When determining the longitudinal loading of the bearing structures of wagons, the calculation was made for the case of a shunting collision of wagons or a "jerk" (tank wagon). The accelerations acting on the bearing structures of the wagons are determined. The research results will help to determine the possibility of extending the operation of the bearing structures of freight wagons that have exhausted their standard service life. It has been established that the indicators of the dynamics of the load-carrying structures of freight wagons with the actual dimensions of the structural elements are within the permissible limits. So, for a gondola wagon, the vertical acceleration of the bearing structure is 4.87 m/s2, for a covered wagon – 5.5 m/s2, for a flat wagon – 5.8 m/s2, for a tank wagon – 4.25 m/s2, for a hopper wagon – 4.5 m/s2. The longitudinal acceleration acting on the bearing structure of a gondola wagon is 38.25 m/s2, for a covered wagon – 38.6 m/s2, for a flat wagon – 38.9 m/s2, for a tank wagon – 27.4 m/s2, for a hopper wagon – 38.5 m/s2. This makes it possible to develop a conceptual framework for restoring the effective functioning of outdated freight wagons. The conducted research will be useful developments for clarifying the existing methods for extending the service life of the bearing structures of freight wagons that have exhausted their standard resource

scholarly journals Justifying the prolongation of the service life of the bearing structure of a tank car when using Y25 bogies

2021 ◽  
Vol 3 (7 (111)) ◽  
pp. 6-14
Author(s):  
Oleksij Fomin ◽  
Alyona Lovska ◽  
Kseniia Ivanchenko ◽  
Ievgen Medvediev
Keyword(s):  
Service Life ◽  
Software Package ◽  
Equations Of Motion ◽  
Simulation Software ◽  
Load Bearing ◽  
Runge Kutta Method ◽  
Design Service Life ◽  
Reported Study ◽  
Mathcad Software ◽  
Bearing Structure

This paper substantiates the use of Y25 bogies under tank cars in order to prolong their service life. The reported study has been carried out for a tank car with rated parameters, as well as the actual ones, registered during full-scale research. Mathematical modeling was performed to determine the basic indicators of the tank car dynamics. The differential equations of motion were solved by a Runge-Kutta method using the Mathcad software package (USA). It was established that the use of Y25 bogies under a tank car with rated parameters could reduce the acceleration of its bearing structure by almost 39 % compared to the use of standard 18‒100 bogies. Applying the Y25 bogies under a tank car with the actual parameters reduces the acceleration of its load-bearing structure by almost 50 % compared to the use of standard 18‒100 bogies. The derived acceleration values were taken into consideration when calculating the bearing structure of a tank car for strength. The calculation was performed using the SolidWorks Simulation software package (France). The resulting stress values are 18 % lower than the stresses acting on the load-bearing structure of a tank car equipped with 18‒100 bogies. For the load-bearing structure of a tank car with the actual parameters, the maximum equivalent stresses are 16 % lower than the stresses when the 18‒100 bogies are used. The design service life of the load-bearing structure of a tank car was estimated taking into consideration the use of Y25 bogies. The calculations showed that the design service life of the bearing structure of a tank car equipped with Y25 bogies is more than twice as high as that obtained for 18‒100 bogies. The study reported here would contribute to compiling recommendations for prolonging the service life of the load-bearing structures of tank cars

scholarly journals ANALYSIS OF DYNAMIC LOADING OF IMPROVED CONSTRUCTION OF A TANK CONTAINER UNDER OPERATIONAL LOAD MODES

2019 ◽  
Vol 2 ◽  
pp. 61-70
Author(s):  
Oleksij Fomin ◽  
Alyona Lovska ◽  
Oleksandr Gorobchenko ◽  
Serhii Turpak ◽  
Iryna Kyrychenko ◽  
...  
Keyword(s):  
Dynamic Loading ◽  
Dynamic Load ◽  
Operating Conditions ◽  
Dynamic Loads ◽  
The Finite Element Method ◽  
Operational Load ◽  
International Transport ◽  
Improvement Measures ◽  
Cargo Transportation

An increase in the volume of bulk cargo transportation through international transport corridors necessitates the commissioning of tank containers. Intermodalization of a tank container predetermines its load in various operating conditions depending on the type of vehicle on which it is carried: aviation, sea, air or rail. The analysis of the operating conditions of tank containers, as well as the regulatory documents governing their workload, led to the conclusion that the most dynamic loads acting on the supporting structures during transportation by rail. Namely, during the maneuvering collision of a wagon-platform, on which there are tank containers. In this case, it is stipulated that for a loaded tank container, the dynamic load is assumed to be 4g, and for an empty (for the purpose of checking the reinforcement) – 5g. It is important to note that when the tank container is underfilled with bulk cargo and taking into account movements of fittings relative to fittings, the maximum value of dynamic load can reach significantly larger values. Therefore, in order to ensure the strength of tank containers, an improvement of their structures has been proposed by introducing elastic-viscous bonds into the fittings. To determine the dynamic loading of the tank container, taking into account the improvement measures, mathematical models have been compiled, taking into account the presence of elastic, viscous and elastic-viscous bonds between the fittings, stops and fittings. It is established that the elastic bond does not fully compensate for the dynamic loads acting on the tank container. The results of mathematical modeling of dynamic loading, taking into account the presence of viscous and elastic-viscous coupling in the fittings, made it possible to conclude that the maximum accelerations per tank container do not exceed the normalized values. The determination of the dynamic loading of the tank container is also carried out by computer simulation using the finite element method. The calculation takes place in the software package CosmosWorks. The maximum values of accelerations are obtained, as well as their distribution fields relative to the supporting structure of the tank container. The developed models are verified by the Fisher criterion. The research will contribute to the creation of tank containers with improved technical, operational, as well as environmental characteristics and an increase in the efficiency of the liquid cargo transportation process through international transport corridors.

Dynamic Analysis of Mechanical Systems With Clearances—Part 1: Formation of Dynamic Model

1971 ◽  
Vol 93 (1) ◽  
pp. 305-309 ◽  
Author(s):  
S. Dubowsky ◽  
F. Freudenstein
Keyword(s):  
Equations Of Motion ◽  
Operating Conditions ◽  
Coupled Systems ◽  
Dynamical Response ◽  
Dynamic Force ◽  
Dynamical Equations ◽  
Mechanical Joint ◽  
The Impact ◽  
Insight Into

A mathematical model of an elastic mechanical joint with clearances has been formulated and the dynamical equations of motion derived (Part I). The model, which we have called an Impact Pair, is basic to the determination of the dynamical response of mechanical and electromechanical systems with clearances, including determination of dynamic force amplification, frequency response, time-displacement characteristics, and other dynamic characteristics. Whenever possible, the results for the impact pair under various operating conditions are illustrated by graphs, which may also offer some insight into the behavior of clearance-coupled systems.

scholarly journals ДИНАМІЧНА РЕАКЦІЯ ТА СТІЙКІСТЬ ПОШКОДЖЕНОЇ КОНСТРУКЦІЇ ТРАНСПОРТНОГО ЛІТАКА

2020 ◽  
pp. 173-180
Author(s):  
Є. Ю. Іленко ◽  
В. М. Онищенко
Keyword(s):  
Dynamic Stability ◽  
Equations Of Motion ◽  
Initial Perturbation ◽  
Aerodynamic Characteristics ◽  
Operating Conditions ◽  
Ultimate State ◽  
Main Method ◽  
Operating Load ◽  
The Stability

In the process of designing and operating the aircraft, it is important to determine the ultimate state of the structure, taking into account the dynamic load of the structure and its stability. The ultimate state of the structure is characterized by damage, in which the structure still retains the ability to withstand without catastrophic destruction of the maximum operating load. The main method of studying the stability of the structure is the dynamic method. It allows us to investigate the perturbed motion of a structure as a nonconservative system for some initial perturbation. The monotonic departure of the system from the equilibrium position or its oscillations with increasing amplitudes indicate the instability of the structure. The paper analyzes the effect of damage to the aircraft structure on its dynamic stability based on the determination of the dynamic response of the aircraft to some non-stationary perturbation, for example, on the action of a turbulent atmosphere. The method of computational analysis is used to study the dynamic stability of the structure. The basis of this method is mathematical modeling (MM) of the operation of the aircraft in the form of a system of equations of motion and deformation of the structure. The problem of dynamic aeroelasticity is considered - the behavior of the elastic damaged structure of the aircraft in the air flow to the initial perturbation. On the basis of computer simulation, the dynamic stability of the elastic structure, its oscillating or quasi-static (aperiodic) deformation motion within the flight range of the aircraft is estimated. On the basis of parametric researches the limits of instability of a design at the set damages for typical operating conditions are estimated. The relevance of the direction focused on the creation and advanced operation of MM aircraft - their mathematical backups in the process of design and operation of aircraft due to the complexity and limited capabilities of ground experimental installations and flight experiment. It is noted that the condition for the application of this method is the formed MM operation of the aircraft and the availability of information on the mass-inertial, stiffness and aerodynamic characteristics of the aircraft.

scholarly journals Determination of the dynamic load of the carrying structure of the hopper wagon with the actual dimensions of structural elements

2021 ◽  
Vol 1 (1(57)) ◽  
pp. 6-11
Author(s):  
Oleksij Fomin ◽  
Alyona Lovska ◽  
Pavel Skok ◽  
Ivan Rogovskii
Keyword(s):  
Mathematical Modeling ◽  
Dynamic Loading ◽  
Software Package ◽  
Degrees Of Freedom ◽  
Field Studies ◽  
Middle Part ◽  
Structural Elements ◽  
Supporting Structure ◽  
Mathcad Software

The object of research is the supporting structure of the pellet wagon with the actual dimensions of the supporting elements. One of the most problematic areas is the determination of the indicators of dynamics and strength of the supporting structure of the hopper wagon with the actual dimensions of the structural elements. A study of the dynamic loading of the supporting structure of the hopper wagon was carried out. At the same time, the actual dimensions of the structural elements were determined by means of field studies. Mathematical modeling of the dynamic loading of the load-carrying structure of a hopper wagon with the actual dimensions of structural elements was carried out by means of mathematical modeling. The studies were carried out in a flat coordinate system. The presence of three degrees of freedom of the supporting structure of the hopper wagon was taken into account: vibrations of twitching, bouncing and galloping. Differential equations were solved in the MathCad software package. In doing so, they were reduced to the Cauchy normal form, and then integrated using the Runge-Kutta method. It was found that the maximum value of the acceleration acting on the supporting structure of the hopper wagon is 38.5 m/s2, which is 2.7% higher than the acceleration of the supporting structure with nominal dimensions. Computer simulation of the dynamic loading of the supporting structure of the hopper wagon was carried out. The calculation was carried out using the finite element method in the SolidWorks Simulation (CosmosWorks) software package. It was found that the maximum accelerations are concentrated in the middle part of the supporting structure of the hopper wagon and amount to 36.2 m/s2. The F-criterion was used to verify the developed model. The calculations showed that the calculated value of the criterion is Fc = 1.09 and is less than the table value Ft = 3.29. The adequacy hypothesis is not rejected. The natural frequencies and vibration modes of the hopper wagon supporting structure were determined. It has been established that the values of natural vibration frequencies of the hopper wagon bearing structure with the actual dimensions of the structural elements are within the permissible limits. The research will contribute to the creation of relevant developments to extend the service life of wagons that have exhausted their standard resource, as well as to increase the efficiency of railway transport operation.

scholarly journals Research of the Vertical Dynamics of the Supporting Structures of Freight Cars Made of Round Pipes

2021 ◽  
pp. 104-114
Author(s):  
O. V. Fomin ◽  
A. O. Lovska
Keyword(s):  
Mathematical Modeling ◽  
Dynamic Loading ◽  
Software Package ◽  
Equations Of Motion ◽  
Mass Center ◽  
Runge Kutta Method ◽  
Spring Suspension ◽  
The Creation ◽  
Mathcad Software ◽  
Supporting Structures

Purpose. This study is aimed at determining the vertical dynamics of supporting structures of freight cars made of round pipes. Methodology. Mathematical modeling of the dynamic loading of the supporting structures of the main types of freight cars made of round pipes (gondola car, covered car, flat car, hopper car) was carried out. The studies were carried out in a plane coordinate system – the XZ plane. At the same time, it was taken into account that the car is moving in an elastic-viscous track so that the reactions of the track are proportional to both its deformation and the rate of this deformation. The studies were carried out for the case of empty cars. The joint inequality is described by a periodic function. The calculation was performed at a speed of 80 km/h. Differential equations of motion were solved in the MathCad software package using the Runge-Kutta method. Findings. Based on the mathematical modeling of the dynamic loading of the supporting structures of cars made of round pipes, the main indicators of their dynamics were obtained: accelerations acting on the supporting structures in the mass center, forces acting in the spring suspension of bogies, dynamics coefficients. For gondola car, covered car, and hopper car, the acceleration at the mass center of the supporting structure is within 0.4 g, and for a flat car – 0.5 g. It was found that the obtained indicators of the dynamics of cars made of round pipes are within the permissible limits. The accelerations acting on the supporting structures of cars made of round pipes are almost the same as those obtained for prototype cars. At the same time, the motion of cars is assessed as "excellent" for gondola car, covered car, and hopper car and "good" for flat car. Originality. Mathematical modeling of the dynamic loading of the supporting structures of cars from round pipes was carried out and the main indicators of their dynamics were obtained. Practical value. The research carried out will contribute to the creation of recommendations for the design of supporting structures of freight cars of round pipes, and can also be useful developments in the creation of innovative car designs.

scholarly journals The Dynamic and Strength Analysis of an Articulated Covered Wagon with the Circular Pipe Design

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1398
Author(s):  
Oleksij Fomin ◽  
Alyona Lovska ◽  
Juraj Gerlici ◽  
Yuliia Fomina ◽  
Ján Dižo ◽  
...  
Keyword(s):  
Dynamic Loading ◽  
Longitudinal Axis ◽  
Operating Conditions ◽  
The Body ◽  
Weld Strength ◽  
Strength Analysis ◽  
Technical Solution ◽  
Circular Pipes ◽  
Loaded Part ◽  
Bearing Structure

An articulated covered wagon design was developed. The wagon feature is that the body-bearing elements are made of circular pipes. This technical solution made it possible to reduce the tare weight of the wagon while ensuring the strength conditions. Mathematical simulation of the dynamic loading of the developed articulated covered wagon design was carried out under the main operating conditions. In the calculations of the observed quantities, an application of symmetry with regard to the longitudinal axis of the wagon was used. The accelerations, as the components of the dynamic load acting on the wagon, were determined. The dynamic loading computer simulation results of the developed wagon design are also presented. The strength analysis of the articulated covered wagon supporting structure made it possible to conclude that the strength indexes were within the allowed limits. The wagon bearing structure was analyzed for fatigue strength. The weld strength analysis results of the most loaded part of the wagon-bearing structure are presented. The results obtained for the desired quantities revealed their symmetrical distribution in the wagon structure. This research will contribute to improving the efficiency of railway transport operation.

Simulation and Contrast Analysis of tem Images of Cracks

1990 ◽  
Vol 48 (1) ◽  
pp. 578-579
Author(s):  
D. Goyal ◽  
A. H. King
Keyword(s):  
Displacement Vector ◽  
Crack Tip ◽  
Perfect Crystal ◽  
Operating Conditions ◽  
Displacement Fields ◽  
Fringe Contrast ◽  
Orthogonal Geometry ◽  
Moire Fringe ◽  
Moiré Fringe

TEM images of cracks have been found to give rise to a moiré fringe type of contrast. It is apparent that the moire fringe contrast is observed because of the presence of a fault in a perfect crystal, and is characteristic of the fault geometry and the diffracting conditions in the TEM. Various studies have reported that the moire fringe contrast observed due to the presence of a crack in an otherwise perfect crystal is distinctive of the mode of crack. This paper describes a technique to study the geometry and mode of the cracks by comparing the images they produce in the TEM because of the effect that their displacement fields have on the diffraction of electrons by the crystal (containing a crack) with the corresponding theoretical images. In order to formulate a means of matching experimental images with theoretical ones, displacement fields of dislocations present (if any) in the vicinity of the crack are not considered, only the effect of the displacement field of the crack is considered.The theoretical images are obtained using a computer program based on the two beam approximation of the dynamical theory of diffraction contrast for an imperfect crystal. The procedures for the determination of the various parameters involved in these computations have been well documented. There are three basic modes of crack. Preliminary studies were carried out considering the simplest form of crack geometries, i. e., mode I, II, III and the mixed modes, with orthogonal crack geometries. It was found that the contrast obtained from each mode is very distinct. The effect of variation of operating conditions such as diffracting vector (), the deviation parameter (ω), the electron beam direction () and the displacement vector were studied. It has been found that any small change in the above parameters can result in a drastic change in the contrast. The most important parameter for the matching of the theoretical and the experimental images was found to be the determination of the geometry of the crack under consideration. In order to be able to simulate the crack image shown in Figure 1, the crack geometry was modified from a orthogonal geometry to one with a crack tip inclined to the original crack front. The variation in the crack tip direction resulted in the variation of the displacement vector also. Figure 1 is a cross-sectional micrograph of a silicon wafer with a chromium film on top, showing a crack in the silicon.

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