scholarly journals Dynamic load simulation of the machine nodes containing interacting rollers

2021 ◽  
Vol 7 (2) ◽  
pp. 153-159
Author(s):  
D.I. Perminova ◽  
Keyword(s):  
Contact Problem ◽  
Dynamic Model ◽  
Dynamic Load ◽  
Dynamic Loads ◽  
Interaction Forces ◽  
Direct Modeling ◽  
Pressure Changes ◽  
Load Simulation

The article presents a dynamic model of interaction of rollers on the example of printing cylinders of an offset machine. Based on the solution of the contact problem, the interaction forces of the cylinders are determined, direct modeling of dynamic loads and vibrations is carried out, the amplitudes of vibrations and pressure changes are determined. Options for reducing loads are considered. The disadvantages of existing models of printing machines are analyzed and taken into account.

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.

Comparing Shock, Random and Sine Vibration Loads of the Electronic Equipment

2005 ◽  
Author(s):  
Frank Fan Wang
Keyword(s):  
Dynamic Load ◽  
Random Vibration ◽  
Sine Wave ◽  
Electronic Equipment ◽  
Dynamic Loads ◽  
Peak Acceleration ◽  
Maximum Acceleration ◽  
Dynamic Excitations ◽  
Dynamic Damage ◽  
Resonant Point

It is a challenge to correlate different dynamic loads. Often, attempts are made to compare the peak acceleration of sine wave to the root mean square (RMS) acceleration of random vibration and shock. However, peak sine acceleration is the maximum acceleration at one frequency. Random RMS is the square root of the area under a spectral density curve. These are not equivalent. This paper is to discuss a mathematical method to compare different kinds of dynamic damage at the resonant point of the related electronic equipment. The electronic equipment will vibrate at its resonance point when there are dynamic excitations. The alternative excitation at the resonant frequency causes the most damage. This paper uses this theory to develop a method to correlate different dynamic load conditions for electronic equipment. The theory is that if one kind of dynamic load causes the same levels of damaging effects as the other, the levels of vibration can then be related.

The Specific Characteristics of Shock and Blast Impacts on Construction Sites

2021 ◽  
pp. 81-88
Author(s):  
A.A. Komarov ◽  
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Dynamic Loads ◽  
Potential Hazard ◽  
Construction Sites ◽  
Static Loads ◽  
Equivalent Static Loads ◽  
Plane Crash ◽  
Nuclear Plants ◽  
The Impact

The practices of hazardous and unique facilities’ construction imply that specific attention is paid to the issues of safety. Threats associated with crash impacts caused by moving cars or planes are considered. To ensure safety of these construction sites it is required to know the potential dynamic loads and their destructive capacity. This article considers the methodology of reducing dynamic loads associated with impacts caused by moving collapsing solids and blast loads to equivalent static loads. It is demonstrated that practically used methods of reduction of dynamic loads to static loads are based in schematization only of the positive phase of a dynamic load in a triangle forms are not always correct and true. The historical roots of this approach which is not correct nowadays are shown; such approach considered a detonation explosion as a source of dynamic load, including TNT and even a nuclear weapon. Application of the existing practices of reduction of dynamic load to static load for accidental explosions in the atmosphere that occur in deflagration mode with a significant vacuumization phase may cause crucial distortion of predicted loads for the construction sites. This circumstance may become a matter of specific importance at calculations of potential hazard of impacts and explosions in unique units — for instance, in the nuclear plants. The article considers a situation with a plane crash, the building structure load parameters generated at the impact caused by a plane impact and the following deflagration explosion of fuel vapors are determined.

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.

scholarly journals The behaviour of roof gable walls under the effect of earthquake load

2010 ◽  
Vol 10 (2) ◽  
pp. 251-263 ◽  
Author(s):  
M. Kamanli ◽  
F. S. Balik
Keyword(s):  
Dynamic Load ◽  
Shaking Table ◽  
Dynamic Loads ◽  
Roof System ◽  
Earthquake Loads ◽  
Research Department ◽  
Earthquake Research ◽  
Earthquake Load

Abstract. In this study, the effect of earthquake loads on roof gable walls and the behaviours of these roof gable walls are investigated. In preparation of the study, two experiments on cradle roof system which gets and does not get any loads off the roof members were carried out in all. The experiments were performed on the shaking table in Earthquake Research Department of General Directorate of Disaster Affairs. Through the experiments, some considerable results were obtained on the behaviours of roof gable walls under the effect of horizontal dynamic loads. The results obtained at the end of these examinations are given and discussed. Furthermore, suggestions to make the brick gable walls more reliable against the loads of earthquake are given. When the results of the experiments were generally taken into consideration, it was realized that the gable walls in both roof systems would partly or completely collapse even under the effect of a little horizontal dynamic load.

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 A Computer Program for Dynamic Load Simulation of Spur Gears with Asymmetric and Symmetric Teeth

2012 ◽  
Vol 02 (05) ◽  
pp. 239-245
Author(s):  
Fatih Karpat ◽  
Stephen Ekwaro-Osire ◽  
Esin Karpat
Keyword(s):  
Computer Program ◽  
Dynamic Load ◽  
Spur Gears ◽  
Load Simulation

scholarly journals Fatigue Life Characteristics of Segmental Lining Structure for the Shallow Buried Metro Tunnel under the Dynamic Load of a High-Speed Railway

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Wangping Qian ◽  
Taiyue Qi ◽  
Qing Zhao ◽  
Bingrong Pu ◽  
Jin Zhang ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Fatigue Failure ◽  
Dynamic Load ◽  
High Speed ◽  
Dynamic Loads ◽  
High Speed Railway ◽  
Segmental Lining ◽  
Lining Structure ◽  
Metro Tunnel

Shallow buried shield metro tunnels constructed underneath subgrade project of high-speed railways are becoming increasingly common in China, but the lower metro tunnel bears the fatigue effect of dynamic load induced by the upper high-speed railway, so the long-term durability of segmental lining is a nonnegligible problem. The segmental lining structure of metro tunnel is in a state of static-dynamic loads for a long time, especially when a high-speed railway passes above the metro line, and the long-term durability of segmental lining needs further research. Based on theoretical analysis, the effect of different forms of loads on the fatigue life was analyzed, the change law of the static-dynamic loads on segmental lining was summarized, and the method was put forward to evaluate the fatigue life characteristics of segmental lining. The research results reveal that the additional dynamic load is the fundamental reason for the fatigue failure of the structure, and the existence of static load can cause and accelerate the occurrence of structural fatigue failure simultaneously. The results indicate that the fatigue life decreases gradually with the increase of static-dynamic load. Based on coupling analysis of static-dynamic loads of segmental lining, the fatigue life increases first and then decreases with the increase of buried depth of metro tunnel, and it remains unchanged when the depth exceeds a certain value. According to the actual metro tunnel engineering, by using ABAQUS software, a three-dimensional numerical simulation was carried out to analyze the characteristics of the fatigue life and evolution rules of segmental lining. Based on the modified fatigue life formula and metro service life, the optimization design of the buried depth was carried out to determine the most reasonable range of the buried depth. This study provides a valuable reference for safe operation and long-term durability of metro tunnels under high-speed railways.

Dynamic Interactions Between the Rolling Element and the Cage in Rolling Bearing Under Rotational Speed Fluctuation Conditions

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Wenbing Tu ◽  
Ya Luo ◽  
Wennian Yu
Keyword(s):  
Dynamic Model ◽  
Rotational Speed ◽  
Rolling Bearing ◽  
Nonlinear Dynamic Model ◽  
Dynamic Interactions ◽  
Interaction Forces ◽  
Rolling Element ◽  
Speed Fluctuation ◽  
Rolling Elements ◽  
Fluctuation Frequency

Abstract A nonlinear dynamic model is proposed to investigate the dynamic interactions between the rolling element and cage under rotational speed fluctuation conditions. Discontinuous Hertz contact between the rolling element and the cage and lubrication and interactions between rolling elements and raceways are considered. The dynamic model is verified by comparing simulation result with the published experimental data. Based on this model, the interaction forces and the contact positions between the rolling element and the cage with and without the rotational speed fluctuation are analyzed. The effects of fluctuation amplitude, fluctuation frequency, and cage pocket clearance on the interaction forces between the rolling element and the cage are also investigated. The results show that the fluctuation of the rotational speed and the cage pocket clearance significantly affects the interaction forces between the rolling element and the cage.

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