Experimental Determination of Dynamic Loading in a Drive Chain with Transverse Vibrations as a String with Fixed Ends

2020 ◽  
pp. 3-10 ◽  
Author(s):  
S.V. Palochkin ◽  
P.N. Rudovskiy
Keyword(s):  
Experimental Data ◽  
Dynamic Loading ◽  
Dynamic Load ◽  
Test Procedure ◽  
Dynamic Loads ◽  
Automated System ◽  
Tension Force ◽  
Machine Drive ◽  
Transverse Vibrations ◽  
A Chain

Chain transmissions are widely used in drives of hoisting-and-transport and ag-ricultural machines, as well as in a number of machine tools and technological equipment in various branches of industry. However, a significant disadvantage of these transmissions is the high vibration activity under high dynamic loading. In this regard, the study of dynamic loads that occur during chain vibrations and affect the operability of the machine drive is one of the essential tasks of its dynamics. The article presents experimental studies performed in order to determine the maximum dynamic loads in a chain transmission of a machine drive with transverse vibrations of the chain. The most common case of transverse vibrations of a chain loop is studied as a string with fixed ends. This type of vibration is typical of chain transmissions with large masses of sprockets and parts attached to them. The article presents a description of an original test bench with an automated system for collecting and processing experimental data and a test procedure. The obtained experimental data are presented in the form of tables and graphical dependences of the maximum dynamic loads on the tension force of the chain average per cycle of vibrations and the amplitude of its transverse vibrations in the center of the span, related to its length. As a result of approximation of the experimental data array, an empirical formula is proposed that can be used in dynamic calculations of the drive. It is established that the maximum dynamic load and its amplitude increases with the increase of the ratio of the amplitude of transverse vibrations of the chain in the middle of its span to its length and the initial tension force of the chain. The ratio of the dynamic load amplitude to the tension force of the chain decreases with the increase of the latter.

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 deformability of the stress-strained concrete strips between the cracks during the short-term dynamic loading

2020 ◽  
Vol 315 ◽  
pp. 07002
Author(s):  
Zaur Galyautdinov ◽  
Oleg Kumpyak ◽  
Daud Galyautdinov
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Dynamic Loading ◽  
Experimental Research ◽  
Inclination Angle ◽  
Dynamic Load ◽  
Statistic Analysis ◽  
Theoretical Studies ◽  
Short Term ◽  
Experimental And Theoretical Studies

The formation of non-intersecting cracks in stress-strained ferroconcrete elements leads to separation of concrete strips between the cracks. The results of the experimental research indicate a significant decrease of the durability and deformability of the stress-strained concrete strips between cracks both under static and short-term dynamic loading. At the same time physico-mechanical properties depend on the straining deformations and rebars’ inclination angle towards the cracks. The existing theoretical and experimental results evaluate only the durability of the concrete strips between the cracks. The current paper presents the results of experimental and theoretical studies on the dynamic deformability of the stress-strained discs between the cracks. The statistic analysis of the experimental data is done; on the basis of the analysis we suggest the dependencies, characterizing the deformability of the concrete strips during the short-term dynamic load depending on the level of the straining deformations and rebars’ inclination angle towards the cracks.

Dynamic Loading of Synchronous Belts

2000 ◽  
Vol 124 (1) ◽  
pp. 79-85 ◽  
Author(s):  
Tomas Johannesson ◽  
Martin Distner
Keyword(s):  
Experimental Data ◽  
Dynamic Loading ◽  
Dynamic Load ◽  
Coulomb Friction ◽  
Static Load ◽  
Belt Drives ◽  
History Effects ◽  
Timing Belt ◽  
Load Conditions ◽  
Good Agreement

In automotive timing belt drives friction history effects must be taken into concern due to rapidly changing loads. Here a spring based model capable of handling dynamic load conditions is presented. The model also covers partial meshing effects and utilizes Coulomb friction. The model shows good agreement with experimental data found in literature. It is proven that when simulating synchronous belt drives during rapidly changing load conditions, using models for quasi-static load conditions stepwise are not sufficient.

scholarly journals TO ASSESSMENT OF THE VALUE OF DYNAMIC LOAD OF FORESTRY MACHINES FROM THE INSTALLATION PLACE OF ITS SAFETY DEVICES

2021 ◽  
Vol 11 (2) ◽  
pp. 166-174
Author(s):  
Pavel Scheblykin ◽  
Nikolay Borodin ◽  
R. Borovikov
Keyword(s):  
Mathematical Model ◽  
Dynamic Load ◽  
Kinematic Chain ◽  
Dynamic Loads ◽  
Elastic Deformations ◽  
Safety Devices ◽  
Machine Drive ◽  
Computer Calculations ◽  
Dynamic Moment

An integral part of the drive elements of machines in forestry are devices that ensure their protection against breakdowns during overloads. Safety devices can be installed on various parts of the kinematic chain of the machine drive elements: at the beginning, at the end or in the middle, and can also be built into the working unit (body). It is most advisable to install fuses closer to the end of the drive lines of the kinematic chain of the machine. If torque safety devices are installed at the beginning or in the middle of the drive, they are not in the overload zone (more often, overload occurs next to the working unit or directly on it). Under these conditions, the drive links of the kinematic chain are subject to overloads of various magnitudes. With distance from the place of occurrence of overload, the value of the value of the dynamic moment decreases due to elastic deformations and friction losses in the drive links of the machine. Consequently, there is a breakdown or destruction of parts and components of the drive, and the fuse itself does not work. Thus, in this article, using a calculated mathematical model of the actuation process of safety devices using a computer, calculations were carried out to determine the values of dynamic loads and an assessment was given in the case of installing a fuse at the beginning and at the end of the kinematic chain of the machine drive

scholarly journals Study of the Influence of Nonlinear Dynamic Loads on Elastic Modulus of Carbonate Reservoir Rocks

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8559
Author(s):  
Evgenii Riabokon ◽  
Mikhail Turbakov ◽  
Nikita Popov ◽  
Evgenii Kozhevnikov ◽  
Vladimir Poplygin ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Dynamic Loading ◽  
Dynamic Load ◽  
Nonlinear Dynamic ◽  
Carbonate Reservoir ◽  
Dynamic Loads ◽  
Testing System ◽  
Strain Rates ◽  
Reservoir Rocks ◽  
Rate Dynamic

The paper presents the results of the experimental investigation of carbonate reservoir rocks subjected to quasistatic and nonlinear dynamic loads. During the quasistatic loading the zones of linear elasticity were determined. Dynamic loading of samples was performed at several frequencies and load amplitudes using a testing system. There were two zones found in which the elastic modulus changes nonlinearly in terms of dynamic load frequency. While the frequency of the dynamic load increases from 0 to 10 Hz the dynamic elastic modulus rises according to logarithmic law; while the frequency increases from 10 to 60 Hz elastic modulus rises according to a power law for each load amplitude. The amplitude of the longitudinal strain and phase shift decreases with increasing frequency of the dynamic load. Under the higher strain rates the rock gets stiffer in comparison with rock subjected to smaller strain rate dynamic loading. Saturation of rock samples with distilled water flattening the dependencies of dynamic Young’s modulus on frequency.

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.

Pore Pressure Build-up of Silt Soft Clay under Dynamic Loading at Zhoushan Islands

2012 ◽  
Vol 594-597 ◽  
pp. 460-464
Author(s):  
Qian Shi ◽  
Kui Zhou ◽  
Qiang Li
Keyword(s):  
Pore Pressure ◽  
Dynamic Loading ◽  
Dynamic Load ◽  
Soft Clay ◽  
Test System ◽  
Dynamic Responses ◽  
Minor Effect ◽  
Consolidation Pressure ◽  
Anisotropic Consolidation ◽  
Pore Pressure Build Up

The mechanism of dynamic tri-axial test is introduced in this paper and the dynamic responses of silt soft clay at Zhoushan are studied using a dynamic tri-axial test system. The laws of pore pressure build-up of the silt clay are obtained which are affected by the consolidation pressure and dynamic load. The greater the consolidation pressure and the dynamic loading is, the more the build-up of pore pressure is. However, the dynamic load has minor effect on pore pressure build-up under the anisotropic consolidation.

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.

Transient Thermoelastohydrodynamic Study of Tilting-Pad Journal Bearings Under Dynamic Loading

1998 ◽  
Vol 120 (2) ◽  
pp. 405-409 ◽  
Author(s):  
P. Monmousseau ◽  
M. Fillon ◽  
J. Freˆne
Keyword(s):  
Steady State ◽  
Dynamic Loading ◽  
Dynamic Load ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Maximum Temperature ◽  
Tilting Pad ◽  
Transient Period ◽  
Final Steady State ◽  
Tilting Pad Journal Bearings

Nowadays, tilting-pad journal bearings are submitted to more and more severe operating conditions. The aim of this work is to study the thermal and mechanical behavior of the bearing during the transient period from an initial steady state to a final steady state (periodic). In order to study the behavior of this kind of bearing under dynamic loading (Fdyn) due to a blade loss, a nonlinear analysis, including local thermal effects, realistic boundary conditions, and bearing solid deformations (TEHD analysis) is realized. After a comparison between theoretical results obtained with four models (ISO, ADI, THD, and TEHD) and experimental data under steady-state operating conditions (static load Ws), the evolution of the main characteristics for three different cases of the dynamic load (Fdyn/Ws < 1, Fdyn/Ws = 1 and Fdyn//Ws > 1) is discussed. The influence of the transient period on the minimum film thickness, the maximum pressure, the maximum temperature, and the shaft orbit is presented. The final steady state is obtained a long time after the appearance of a dynamic load.

Reinforced concrete slabs on yielding supports under dynamic load

2021 ◽  
Vol 23 (3) ◽  
pp. 109-117
Author(s):  
G. I. Odnokopylov ◽  
Z. R. Galyautdinov ◽  
V. B. Maksimov
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Loading ◽  
Dynamic Load ◽  
High Efficiency ◽  
Experimental Results ◽  
Displacement Velocity ◽  
Concrete Slabs ◽  
Elastic Plastic ◽  
Deformation Stage ◽  
Reinforced Concrete Slabs

The paper presents the experimental results of strength and deformability of reinforced concrete slabs on yielding supports arranged along the perimeter under the dynamic loading. Crushable ring-shaped inserts deforming at the elastic, plastic and curing stages are considered as yielding supports. The displacement, velocity and acceleration are evaluated depending on the deformation stage of yielding supports. The high efficiency is shown for the use of yielding supports, which leads to a significant reduction in the structure displacement, strain, and stress.

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