ANALYSIS OF THE INFLUENCE OF ANGULAR SPEED OF ROTATION OF A PIPELINE WITH LIQUID ON THE DEVELOPMENT OF DYNAMIC PROCESSES

2019 ◽  
pp. 48-51
Author(s):  
O. Limarchenko ◽  
M. Sapon
Keyword(s):  
Mathematical Model ◽  
Dynamic Behavior ◽  
Liquid Flow ◽  
Dynamic Equilibrium ◽  
Longitudinal Axis ◽  
Angular Speed ◽  
System Dynamic ◽  
Dynamic Processes ◽  
Alternative States ◽  
Combined Motion

The article deals with construction of a mathematical model of combined motion of a rigid pipeline conveying liquid. The pipeline performs rotation about the longitudinal axis. For different velocities of liquid flow and pipeline rotation we determine special features of the system dynamic behavior. It was shown that oscillations in the system are developed near rectilinear and two alternative positions of dynamic equilibrium. Characteristics of phenomena manifested on transition to oscillations relative to alternative states are given.

Dynamic Stability of Hovercraft in Heave

1970 ◽  
Vol 37 (4) ◽  
pp. 895-900 ◽  
Author(s):  
H. J. Davies ◽  
G. A. Poland
Keyword(s):  
Mathematical Model ◽  
Dynamic Behavior ◽  
Dynamic Stability ◽  
Equilibrium Position ◽  
Forced Oscillation ◽  
Dynamic Equilibrium ◽  
Forced Oscillations ◽  
Two Dimensional ◽  
Oscillation Characteristics ◽  
Nonlinear Nature

The regimes of flow governing the dynamic behavior of a two-dimensional mathematical model of an edge-jet Hovercraft in heaving motion are described and the equations associated with such regimes derived. Both the free and forced-oscillation characteristics are studied. The nonlinear nature of the system manifests itself, in the case of the forced oscillations, as a shift in the dynamic equilibrium position resulting in a loss of mean hoverheight.

TO THE STABILITY OF TANK VEHICLES IN THE BRAKE MODE

2019 ◽  
pp. 27-32
Author(s):  
Denys Popelysh ◽  
Yurii Seluk ◽  
Sergyi Tomchuk
Keyword(s):  
Mathematical Model ◽  
Control Systems ◽  
Distribution Systems ◽  
Traffic Accidents ◽  
Road Traffic ◽  
Center Of Mass ◽  
Dynamic Processes ◽  
Course Stability ◽  
The Stability ◽  
Tank Vehicles

This article discusses the question of the possibility of improving the roll stability of partially filled tank vehicles while braking. We consider the dangers associated with partially filled tank vehicles. We give examples of the severe consequences of road traffic accidents that have occurred with tank vehicles carrying dangerous goods. We conducted an analysis of the dynamic processes of fluid flow in the tank and their influence on the basic parameters of the stability of vehicle. When transporting a partially filled tank due to the comparability of the mass of the empty tank with the mass of the fluid being transported, the dynamic qualities of the vehicle change so that they differ significantly from the dynamic characteristics of other vehicles. Due to large displacements of the center of mass of cargo in the tank there are additional loads that act vehicle and significantly reduce the course stability and the drivability. We consider the dynamics of liquid sloshing in moving containers, and give examples of building a mechanical model of an oscillating fluid in a tank and a mathematical model of a vehicle with a tank. We also considered the method of improving the vehicle’s stability, which is based on the prediction of the moment of action and the nature of the dynamic processes of liquid cargo and the implementation of preventive actions by executive mechanisms. Modern automated control systems (anti-lock brake system, anti-slip control systems, stabilization systems, braking forces distribution systems, floor level systems, etc.) use a certain list of elements for collecting necessary parameters and actuators for their work. This gives the ability to influence the course stability properties without interfering with the design of the vehicle only by making changes to the software of these systems. Keywords: tank vehicle, roll stability, mathematical model, vehicle control systems.

scholarly journals Change of photosensitizer fluorescence at its diffusion in viscous liquid flow

2016 ◽  
Vol 09 (02) ◽  
pp. 1650005 ◽  
Author(s):  
Valeriya S. Maryakhina ◽  
Vyacheslav V. Gun’kov
Keyword(s):  
Mathematical Model ◽  
Viscous Liquid ◽  
Liquid Flow ◽  
Fluorescence Spectra ◽  
Inflection Point ◽  
Biological Tissues ◽  
Transparency Window ◽  
Biological Liquid ◽  
The Mathematical Model

In this paper, the mathematical model of distribution of the injected compound in biological liquid flow has been described. It is considered that biological liquid contains a few phases such as water, peptides and cells. The injected compound (for example, photosensitizer) can interact with peptides and cells. At the time, viscosity of the biological liquid depends on pathology present in organism. The obtained distribution of the compound connects on changes of its fluorescence spectra which are registered during fluorescent diagnostics of tumors. It is obtained that the curves do not have monotonic nature. There is a sharp curves decline in the first few seconds after injection. Intensivity of curves rises after decreasing. It is especially pronounced for wavelength 590[Formula: see text]nm and 580[Formula: see text]nm (near the “transparency window” of biological tissues). Time of inflection point shifts from 8.4[Formula: see text]s to 6.9[Formula: see text]s for longer wavelength. However, difference between curves is little for different viscosity means of the biological liquid. Thus, additional pathology present in organism does not impact to the results of in vivo biomedical investigations.

scholarly journals Engineering of Light Electric Commercial Vehicle

2020 ◽  
Vol 19 (1) ◽  
pp. 63-75
Author(s):  
R. Dorofeev ◽  
A. Tumasov ◽  
A. Sizov ◽  
A. Kocherov ◽  
A. Meshkov ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Electric Vehicle ◽  
Electric Motor ◽  
Field Tests ◽  
Angular Speed ◽  
Maximum Energy ◽  
Driving Cycle ◽  
Thermal Calculation ◽  
Technical Solutions ◽  
The Mathematical Model

The paper describes the process and results of the development of the light commercial electric vehicle. In order to ensure maximum energy efficiency of the developed vehicle the key parameters of the original electric motor. The article also presents the results of power electronic thermal calculation. For the mathematical model of the vehicle, the driving cycle parameters of the electric platform were determined in accordance with UNECE Regulations No 83, 84. The driving cycle was characterized by four successive urban and suburban cycles. The mathematical model also takes into account the time phases of the cycle, which include idling, vehicle idling, acceleration, constant speed movement, deceleration, etc. The model of the electric part of the vehicle was developed using MatLab-Simulink (SimPowerSystems library) in addition to the mechanical part of the electric car. The electric part included the asynchronous electric motor, the motor control system and the inverter. This model at the output allows to obtain such characteristics of the electric motor as currents, flows and voltages of the stator and rotor in a fixed and rotating coordinate systems, electromagnetic moment, angular speed of rotation of the motor shaft. The developed model allowed to calculate and evaluate the performance parameters of the electric vehicle. Technical solutions of the electric vehicle design were verified by conducting strength calculations. In conclusion, the results of field tests of a commercial electric vehicle are presented.

scholarly journals World Experience in Creating Mathematical Models of Air Springs: Advantages and Disadvantages

2021 ◽  
pp. 25-42
Author(s):  
A. Y Kuzyshyn ◽  
S. A Kostritsia ◽  
Yu. H Sobolevska ◽  
А. V Batih
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Mathematical Models ◽  
Dynamic Behavior ◽  
High Speed ◽  
Vertical Direction ◽  
Rolling Stock ◽  
Air Spring ◽  
Advantages And Disadvantages ◽  
Mechanical Models

Purpose. Taking into account the production and commissioning of modern high-speed rolling stock, the authors are aimed to analyze the currently created mathematical models describing the dynamic behavior of the air spring, systematize them and consider the advantages and disadvantages of each model type. Methodology. For the analysis, a comparative chronological method was used, which makes it possible to trace the development of several points of view, concepts, theories. In accordance with the adopted decision equations, the existing models of air springs were divided into three groups: mechanical, thermodynamic and finite-elements. When analyzing mathematical models, the influence of a number of parameters on the dynamic behavior of the air spring, such as disturbing force frequency, heat transfer, nonlinear characteristics of materials, the shape of the membrane, etc., was considered. Findings. A feature of mechanical models is the determination of input parameters based on the analysis of experimental results, requires access to complex measuring equipment and must be performed for each new model of an air spring separately. Unlike mechanical models, which allow taking into account the damping effect of an air spring in the horizontal and vertical direction, thermodynamic models are mainly focused on studying the dynamic behavior of an air spring in the vertical direction. The use of the finite element method makes it possible to most accurately reproduce the dynamic behavior of an air spring, however, it requires significant expenditures of time and effort to create a finite element model and perform calculations. Originality. Mathematical models of the dynamic behavior of an air spring are systematized, and the importance of their study in conjunction with a spatial mathematical model of high-speed rolling stock is emphasized. Practical value. The analysis of the mathematical models of the dynamic behavior of the air spring shows the ways of their further improvement, indicates the possibility of their use in the spatial mathematical model of the rolling stock in accordance with the tasks set. It will allow, even at the design stage of high-speed rolling stock, to evaluate its dynamic characteristic and traffic safety indicators when interacting with a railway track.

scholarly journals Generalization of research results on the dynamics of continuous wide-strip hot-rolling mills

2018 ◽  
pp. 275-289
Author(s):  
V.V. Verenev
Keyword(s):  
Mathematical Model ◽  
Hot Rolling ◽  
Large Data ◽  
Dynamic Processes ◽  
Technological Parameters ◽  
Rolling Moment ◽  
Rolling Mills ◽  
Wide Strip ◽  
The Impact ◽  
First Time

The aim of the work is to summarize the results of experimental-industrial and theoretical studies of dynamic processes in wide-strip hot rolling mills 1680, 1700, 2000 and 2500. We describe the methods of collecting, storing, identifying, visualizing and mathematical processing of large data arrays, which made it possible to establish new laws and correlations of technological parameters. New results related to the peculiarities of transient processes, their patterns and the use of the latter for the purpose of diagnosing technology and equipment condition are presented. Vibrodynamic processes are described when the strip is captured by the rollers. For the first time, a correlation between the maximum peak moment when the strip is captured and the static rolling moment on the 1680 mill is obtained and substantiated by measuring and statistical modeling. A new mathematical model of the roll line is developed, incorporating the equations of dynamic processes in gears and axles of the gearbox. For the first time, the dynamics of the formation of intercellular tensions in the process of sequential filling and release with a 6-cell band is shown. A complete mathematical model and a computer program for the dynamic interaction of six-group stands of a rolling strip have been developed. A new line of research has been proposed, which includes the search, substantiation and testing of new methods and methods for diagnosing the technical condition of rolling mills based on the use of transients and their parameters in various modes of equipment operation. Proposed and tested in industrial conditions at the mills 1680 and 1700-M are effective ways to reduce the impact loads during the period of the strip capture by the rollers.

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