Study of the dynamics of ТПА 350 automatic mill working stand elements

2020 ◽  
Vol 76 (8) ◽  
pp. 830-840
Author(s):  
S. R. Rakhmanov ◽  
V. V. Povorotnii
Keyword(s):  
Mechanical System ◽  
Dynamic Model ◽  
Maximum Amplitude ◽  
Calculation Scheme ◽  
Dynamic Loads ◽  
Forced Oscillations ◽  
Mass Model ◽  
Automatic Mill ◽  
Hollow Billet ◽  
Oscillation Movement

To form a necessary geometry of a hollow billet to be rolled at a pipe rolling line, stable dynamics of the base equipment of the automatic mill working stand has a practical meaning. Among the forces, acting on its parts and elements, significant by value short-time dynamic loads are the least studied phenomena. These dynamic loads arise during transient interaction of the hollow billet, rollers, mandrel and other mill parts at the forced grip of the hollow billet. Basing of the calculation scheme and dynamic model of the mechanical system of the ТПА 350 automatic mill working stand was accomplished. A mathematical model of dynamics of the system “hollow billet (pipe) – working stand” within accepted calculation scheme and dynamic model of the mechanical system elaborated. Influence of technological load of the rolled hollow billet variation in time was accounted, as well as variation of the mechanical system mass, and rigidity of the ТПА 350 automatic mill working stand. Differential equations of oscillation movement for four-mass model of forked sub-systems of the automatic mill working stand were made up, results of their digital calculation quoted. Dynamic displacement of the stand elements in the inter-roller gap obtained, which enabled to estimate the results of amplitude and frequency characteristics of the branches of the mill rollers setting. It was defined by calculation, that the maximum amplitude of the forced oscillations of elements of the ТПА 350 automatic mill working stand within the inter-roller gap does not exceed 2 mm. It is much higher than the accepted value of adjusting parameters of the deformation center of the ТПА 350 automatic mill. A scheme of comprehensive modernization of the rollers setting in the ТПА 350 automatic mill working stand was proposed. It was shown, that increase of rigidity of rollers setting in the ТПА 350 automatic mill working stand enables to stabilize the amplitude of forced oscillations of the working stand elements within the inter-rollers gap and considerably decrease the induced nonuniform hollow billet wall thickness and increase quality of the rolled pipes at ТПА 350.

Dynamics of exit section of automatic mill of pipe rolling line

2021 ◽  
Vol 77 (2) ◽  
pp. 175-186
Author(s):  
S. R. Rakhmanov
Keyword(s):  
Differential Equations ◽  
Mechanical System ◽  
Technological Process ◽  
Dynamic Models ◽  
Dynamic Processes ◽  
Exit Section ◽  
Pipe Rolling ◽  
Automatic Mill ◽  
Hollow Billet ◽  
Rolling Line

Nonuniformity of pipe wall thickness is one of significant indices, determining quality of hot-rolled seamless pipes. One of the reasons of increased nonuniformity arising is dynamics of exit section mechanisms of pipe rolling line (PRL). Results of study of mandrel holding mechanism dynamics of PRL presented. Dynamic models of exit section, accounting parameters of technological process and inertia of a rolled hollow billet elaborated, which enabled to determine the character of dynamic processes at the exit section of PRL automatic mill. Differential equations of exit section elements motion at the exit section of PRL automatic mill were made up. The solution of the differential equations system was obtained in a numerical form by application of Runge‒Kutta method for correspondent dynamic models of exit section based on the example of calculations for ТПА-350 automatic mill. The pattern of dynamic processes arising at the exit section was specified at realization of the whole technological process of a hollow billet rolling at automatic mill, taking into consideration alternative action from the side of deformation center and mass of the rolled hollow billet. It was shown, that the specified solution of the task for three advanced dynamic models of mechanical system considerably differs from those of the known mathematical models. It was established, that the dynamics of the mandrel holding mechanism of ТПА-350 automatic mill equivalently form the mechanism of finished pipes geometry forming. Analysis of dynamic models of the mill exit section enabled to select the necessary technological and dynamic parameters of the mechanical system, to determine stable modes of hollow billets rolling at the ТПА-350 automatic mill. Results of the study of dynamics of exit section ТПА-350 automatic mill presented. A scheme of modernization of the exit section ТПА-350 automatic mill proposed, which enables to realize rational modes of operation accounting level of mechanical system dynamics and to control quality (geometric parameters) of the rolled pipes.

Torsional Vibrations and Dynamic Loads in a Basic Planetary Gear System

1986 ◽  
Vol 108 (3) ◽  
pp. 348-353 ◽  
Author(s):  
R. August ◽  
R. Kasuba
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Planetary Gear ◽  
Gear System ◽  
Dynamic Loads ◽  
Ring Gear ◽  
Gear Mesh ◽  
Input And Output ◽  
Planetary Gear System ◽  
Three Degrees Of Freedom

An interative method has been developed for analyzing dynamic loads in a light weight basic planetary gear system. The effects of fixed, semi-floating, and fully-floating sun gear conditions have been emphasized. The load dependent variable gear mesh stiffnesses were incorporated into a practical torsional dynamic model of a planetary gear system. The dynamic model consists of input and output units, shafts, and a planetary train. In this model, the sun gear has three degrees of freedom; two transverse and one rotational. The planets, ring gear, and the input and output units have one degree of freedom, (rotation) thus giving a total of nine degrees of freedoms for the basic system. The ring gear has a continuous radial support. The results indicate that the fixed sun gear arrangement with accurate or errorless gearing offers in general better performance than the floating sun gear system.

scholarly journals DYNAMICS OF TRACTION DEVICE OF MINE SUSPENDED MONOREL ROAD

2020 ◽  
Vol 12 (3) ◽  
pp. 410-417
Author(s):  
Viktor GUTAREVICH ◽  
◽  
Marina KONDRATENKO ◽  
Keyword(s):  
Mathematical Model ◽  
Mechanical System ◽  
Structural Parameters ◽  
Low Frequency ◽  
Dynamic Loads ◽  
Pressing Force ◽  
Negative Effect ◽  
Traction Device ◽  
The Difference ◽  
Fatigue Fractures

During the operation of the mine suspension monorail track and traction device form a mechanical system experiencing high dynamic loads associated with implementation of traction and braking forces. Emerging dynamic loads lead to formation of elastic deformations and oscillations that cause vibrations, which leads to displacement of drive wheels and reduces the implementation of traction. The study of the dynamics of traction device is an important step in improving safety and reliability of monorail transport. The aim of the work is to study dynamics of a friction-type traction device moving along a suspended monorail to assess influence of parameters of the elements of device on the vibrations and nature of interaction of drive wheels with monorail. Research methods. Mathematical modeling of the oscillatory processes resulting from interaction of the running gear of the traction device with the monorail is used. Stages of research include drawing up a design diagram oscillations of drive wheels of the traction device interacting with the monorail, developing a mathematical model for the analysis of vibrations caused by moving loads, also assessing the influence of structural parameters of mechanical system under consideration on nature of oscillations. Research results. The developed mathematical model of friction-type traction device movement allows us to establish relationship between parameters of structural elements of its running gear and pressure mechanism, as well as nature of vibrations that arise. As a result, frequencies of the mechanical system under consideration and maximum deviations were found, which allows you to set optimal device parameters to increase traction and increase lifespan of monorail suspended roads. Findings. It was determined that the frequency range of vibration of drive wheels mainly corresponds to the mid-frequency local vibrations of 16–36 Hz. Increasing length of lever for fixing axles of wheels and reducing their radius leads to formation of low-frequency vibrations with a frequency of less than 15 Hz. When length of lever of drive wheels is more than 0.5 m, shoulder of the spring is more than 0.6 m and radius of drive wheels is less than 0.25 m, vibrations with frequencies below 5 Hz can occur. It was found that increasing the length of lever for securing spring increases the oscillation frequency of one drive wheel and reduces frequency of the other. The difference between these frequencies significantly affects changes in the pressure of the wheels against monorail. When difference between frequencies is more than 10–12 Hz, direction of load changes pulsed, with a maximum swing of 0.02 rad, which reduces formation of fatigue fractures of tire wheels, and moments of decrease and increase in pressing force have a negative effect on traction, leading to slippage of drive wheels. When difference between frequencies is less than 10–12 Hz, direction of the load changes sharply, with a maximum swing of 0.03 rad, which increases deformation and formation of fatigue fractures of tire wheels, and short moments of weakening and increase of pressing force, constituting 0.1–0.3 s does not have a significant negative effect on traction.

scholarly journals RESEARCH OF DYNAMICS OF LOW FLOOR BUS / ŽEMAGRINDŽIO AUTOBUSO DINAMINIAI TYRIMAI

2016 ◽  
Vol 7 (5) ◽  
pp. 589-593
Author(s):  
Darius Vainorius ◽  
Arūras Kilikevičius ◽  
Kristina Kilikevičienė ◽  
Nikolaj Šešok ◽  
Igor Iljin
Keyword(s):  
Mechanical System ◽  
Dynamic Model ◽  
Theoretical Research ◽  
The Stability

The article describes the dynamics researches of low floor bus. The goal of research is to determine the stability of mechanical system of low floor bus. Performed the dynamic model of ½ bus which was conducted the theoretical research in Matlab environment. Darbo tyrimų tikslas – išanalizuoti žemagrindžio autobuso dinamines charakteristikas taikant virpesių lygtis. Tikslui pasiekti pirmiausia buvo sudarytas ½ autobuso sistemos dinaminis modelis ir atliktas sistemos modeliavimas žadinant realių amplitudžių reikšmėmis. Sudarytas autobuso sistemos dinaminis modelis leidžia analizuoti charakteringus ir pavojingus autobusui dinaminius virpesius.

A Mechanical Model for Dynamic Behavior of Large Amplitude Liquid Sloshing in Partially Filled Tank Vehicles

2003 ◽  
Author(s):  
Liang Xu ◽  
Liming Dai
Keyword(s):  
Mechanical System ◽  
Dynamic Behavior ◽  
Large Amplitude ◽  
Mechanical Model ◽  
Structure Design ◽  
Liquid Sloshing ◽  
Liquid Motion ◽  
Mass Model ◽  
Longitudinal Dynamic ◽  
Tank Vehicles

A mechanical model of liquid sloshing is developed to investigate the longitudinal dynamic characteristics of partially filled liquid cargo tank vehicles during typical straight-line driving. The dynamic liquid motion is modeled by utilizing a mechanical system that describes the behavior of the liquid motion as a linear spring-mass model augmented with an impact subsystem for longitudinal oscillations. Computer simulation of tank vehicles under rough road conditions is performed by incorporating the forces and moments caused by liquid motion into the pitch plane vehicle model. The fifth wheel loads and the normal axle loads, which are key factors to vehicle structure design, fatigue analysis and vehicle performance characteristics, are computed using the mechanical system approach in order to investigate the influence of liquid motion. This study presents a new approach to investigate the longitudinal dynamic behavior of partially filled tank vehicles under large amplitude liquid sloshing.

scholarly journals Calculating cargo securing elements on a railway platform under the impact of a spatial force system

2019 ◽  
Vol 135 ◽  
pp. 02006 ◽  
Author(s):  
Khabibulla Turanov ◽  
Yadgor Ruzmetov ◽  
Natalia Vlasova
Keyword(s):  
Mathematical Models ◽  
Mechanical System ◽  
Physical Model ◽  
Dynamic Model ◽  
Force System ◽  
Mathematical Solution ◽  
Lateral Forces ◽  
Analytical Formulas ◽  
The Impact ◽  
Simultaneous Influence

Form a design (or dynamic) model on the basis of studying the physical model of a mechanical system (object); build mathematical models of cargo securing with inclined side surfaces of stop elements (bars) with simultaneous influence of longitudinal and lateral forces; perform a mathematical solution of the problem in the form of specific analytical formulas for calculating inclined stop bars as one of the cargo securing elements on the railway platform; make a specific example of the calculation of the forces acting on the cargo securing elements.

scholarly journals Compliant leg behaviour explains basic dynamics of walking and running

2006 ◽  
Vol 273 (1603) ◽  
pp. 2861-2867 ◽  
Author(s):  
Hartmut Geyer ◽  
Andre Seyfarth ◽  
Reinhard Blickhan
Keyword(s):  
Mechanical System ◽  
Legged Locomotion ◽  
Human Locomotion ◽  
The Body ◽  
Phase Changes ◽  
Vertical Oscillation ◽  
Mass Model ◽  
Double Support ◽  
Walking Motion ◽  
The Many

The basic mechanics of human locomotion are associated with vaulting over stiff legs in walking and rebounding on compliant legs in running. However, while rebounding legs well explain the stance dynamics of running, stiff legs cannot reproduce that of walking. With a simple bipedal spring–mass model, we show that not stiff but compliant legs are essential to obtain the basic walking mechanics; incorporating the double support as an essential part of the walking motion, the model reproduces the characteristic stance dynamics that result in the observed small vertical oscillation of the body and the observed out-of-phase changes in forward kinetic and gravitational potential energies. Exploring the parameter space of this model, we further show that it not only combines the basic dynamics of walking and running in one mechanical system, but also reveals these gaits to be just two out of the many solutions to legged locomotion offered by compliant leg behaviour and accessed by energy or speed.

scholarly journals COMPREHENSIVE STUDY OF THE DYNAMICS OF THE RETAINING MECHANISM OF THE AUTOMATIC MILL

2021 ◽  
pp. 76-88
Author(s):  
Suleiman Rakhmanov ◽  
Sergey Zdanevich
Keyword(s):  
Mathematical Models ◽  
Mechanical System ◽  
Technological Process ◽  
Dynamic Models ◽  
Retention Mechanism ◽  
Dynamic Processes ◽  
Longitudinal Rolling ◽  
Automatic Mill ◽  
Rod System ◽  
Output Side

The results of the study of the dynamics of the mechanism for holding the mandrel of an automatic TPA mill are presented. The value of the axial force acting on the mandrel and the rod system of the mechanism of its holding is determined. Developed models of the mandrel retention mechanism have been developed, which made it possible to establish the nature of the development of dynamic processes on the output side of the automatic mill, taking into account the force parameters of the longitudinal rolling process of the sleeve and the parameters of the output side of the automatic mill. Mathematical models of the mandrel retention mechanism have been developed, taking into account the parameters of the technological process and the inertness of the rolled sleeve. The solution of the system of differential equations with variable coefficients is implemented numerically using the Runge-Kutta method for the corresponding dynamic models of the mandrel retention mechanism on the example of calculating the automatic mill TPA 350. The picture of the formation of dynamic processes in the mandrel retention mechanism during the implementation of the entire technological process of pipe production on an automatic mill has been clarified. taking into account the variable impact from the deformation zone and the change in the mass of the rolled sleeve. For various dynamic models, numerical solutions of problems were implemented, which made it possible to select the necessary technological and dynamic parameters of the mechanical system, to assign stable modes of rolling the sleeves on the automatic mill TPA 350. It is shown that the refined solution of the problem for three developed dynamic models of the mechanical system differs significantly from the previously known mathematical models. It has been established that the dynamics of the mechanism for holding the mandrel of the automatic TPA 350 mill is equivalent to the formation of the mechanism for the formation of different wall thickness of pipes. A mechanism for stabilizing the dynamics of the mandrel holding mechanism by separating the sections of the output side of the mill is proposed.

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