scholarly journals Forecasting the influence of vehicle columns with liquid cargoes on bearing systems in agriculture

2020 ◽  
Vol 175 ◽  
pp. 11001
Author(s):  
Sergey Gridnev ◽  
Alexey Budkovoy ◽  
Yuriy Skalko ◽  
Rinat Muchtarov
Keyword(s):  
Nonlinear Oscillations ◽  
Dynamic Pressure ◽  
Moving Load ◽  
Dynamic Effect ◽  
Oscillatory System ◽  
Driven Systems ◽  
Dynamic Coefficients ◽  
Numerical Studies ◽  
Tanker Truck ◽  
Expert Models

Studies have been performed to evaluate the dynamic effect of columns of the same type of agricultural tanker truck on the beam-bearing systems of transport structures during movement in braking mode. The design scheme of the general oscillatory system is selected, a mathematical and numerical model of its behavior is developed, an algorithm for joint nonlinear oscillations is constructed. On the basis of the developed expert models, a computer complex was created using the simulation package of dynamic and event-driven systems Simulink MATLAB systems. Using it, a series of computational experiments was carried out to simulate situations of passage of convoys of cars with different parameters and with different driving modes. Various parameters varied: the speed of the column, the distance between the cars, the speed at the time of the start of braking, the place where the first car began to brake, the amount of steady deceleration, the number of tank compartments, and the value of operational underfilling. Based on the analysis of the results of numerical studies, the features of the dynamic effect of vehicles convoys carrying liquid cargo on load-bearing systems from the standpoint of the emergence of excess dynamic pressure on transport facilities and the need for its consideration are shown. Cases of a dangerous combination of parameters and driving modes are highlighted, and the need to distinguish such columns in a special class of moving load is shown. A significant increase in the dynamic coefficients of deflections in comparison with solid loads is shown. The need for full-scale research in this area with the aim of introducing amendments to regulatory documents has been proved.

Dynamic Performance Analysis on High-Speed Railway Continuous Girder Bridge

2011 ◽  
Vol 280 ◽  
pp. 186-190
Author(s):  
Shou Tan Song ◽  
Ji Wen Zhang ◽  
Xin Yuan
Keyword(s):  
High Speed ◽  
Moving Load ◽  
Damping Ratio ◽  
Dynamic Performance ◽  
Wheel Load ◽  
Dynamic Coefficients ◽  
Bridge Structures ◽  
Continuous Girder Bridge ◽  
Girder Bridge ◽  
Dynamic Performance Analysis

The dynamic performance of continuous girder under the train in a series of speed is studied through examples, and the main conclusions are given in the following. The resonance mechanism of continuous girder is similar to simply supported beam. The vehicle wheel load forms regular moving load series, which induces periodical action and resonance of the bridge. The damping ratio of bridge itself has less effect on the amplitude at the loading stage, but significant effects appear when the load departs from the bridge. The count of continuous spans also has less impact on the dynamic coefficients, so three continuous spans can be adopted for calculation and analysis. Span and fundamental frequency have significant influence on dynamic coefficients of bridge structures. To extend the span of the bridge structure can reduce the dynamic coefficient while keeping its frequency invariant. The fundamental frequencies of different bridges are corresponding to certain resonant speeds, which calls for the attention in the design.

Convergent-Tapered Annular Seals: Analysis and Testing for Rotordynamic Coefficients

1985 ◽  
Vol 107 (3) ◽  
pp. 307-316 ◽  
Author(s):  
D. W. Childs ◽  
J. B. Dressman
Keyword(s):  
Dynamic Pressure ◽  
Momentum Equation ◽  
Computational Method ◽  
Centrifugal Pumps ◽  
Zeroth Order ◽  
Taper Angle ◽  
First Order ◽  
Dynamic Coefficients ◽  
Direct Stiffness ◽  
Annular Seals

A combined analytical-computational method is developed to calculate the pressure field and dynamic coefficients for tapered high-pressure annular seals typical of neck-ring and interstage seals employed in multistage centrifugal pumps. Completely developed turbulent flow is assumed in both the circumferential and axial directions and is modeled by Hirs’ bulk-flow turbulent-lubrication equations. Linear zeroth- and first-order perturbation equations are developed for the momentum equations and continuity equations. The development of the circumferential velocity field is defined from the zeroth-order circumferential-momentum equation, and a leakage relationship is defined from the zeroth-order axial-momentum equation. A short-bearing approximation is used to derive an analytical expression for the first-order (dynamic) pressure gradient. This expression is integrated numerically to define dynamic coefficients for the seal. Numerical results are presented and compared to previous results for straight and tapered seals. The direct stiffness and leakage increase with increasing taper angle, while the remaining dynamic coefficients decrease. An optimal taper angle is shown to exist with respect to (a) the direct stiffness, and (b) the ratio of direct stiffness to leakage. Stiffness increases on the order of 40-50 percent are predicted. Experimental results are presented for seals with three taper angles which show generally good agreement between theory and prediction.

scholarly journals Nonlinear Oscillations of the Yates-Pardee-Goodwin Metabolic Pathway with Coupling — The Role of Exterior Pools

1997 ◽  
Vol 05 (02) ◽  
pp. 285-300
Author(s):  
J.-P. Morillon ◽  
S. Doubabi ◽  
R. Costalat
Keyword(s):  
Metabolic Pathway ◽  
Metabolic Pathways ◽  
Nonlinear Oscillations ◽  
Nonlinear Differential Equations ◽  
Nonlinear Function ◽  
Linear Filter ◽  
Analytic Method ◽  
Control Loop ◽  
Numerical Studies

An analytic method referred to as the harmonic balancing technique has been applied in order to study the effect of diffusion between compartments (coupling between pools) on the Yates-Pardee-Goodwin metabolic pathway. The behaviour of the pathway is modelled on a set of coupled ordinary nonlinear differential equations. This set is transformed into a single feedback control loop with a nonlinear function and a linear filter. It is shown that coupling modifies the linear filter such that the frequency and the amplitude of the oscillations decrease. Further results are then obtained by numerical studies, and compared with the analytical approach and previous stability analysis of metabolic pathways.

Comparative stochastic analysis of the anomalous dynamics of machines under the action of operational defects

2020 ◽  
pp. 25-30
Author(s):  
F.YA. Balitskiy ◽  
A.G. Sokolova
Keyword(s):  
Stochastic Analysis ◽  
Nonlinear Oscillations ◽  
Oscillatory System ◽  
Technical Condition ◽  
Bearing Defects ◽  
Vibroacoustic Diagnostics ◽  
Compressor Installation ◽  
Anomalous Dynamics ◽  
Rotor Type ◽  
Operational Assessment

The possibility of increasing the confidence of vibroacoustic diagnostics of the technical condition of rotor-type machinery is being investigated. The search for additional sensitive and reliable features is based on the analysis of two-dimensional probability distribution densities of vibration amplitudes. This approach allows to assess the degree and character of the nonlinearity of the machine dynamic model as an oscillatory system. An example of diagnosing the technical condition of a compressor installation is given, showing the possibility of an indirect operational assessment of the accomplished repair. Keywords vibroacoustic diagnostics, nonlinear oscillations, stochastic connection, sliding bearing, defects. [email protected]

scholarly journals Weighing in motion and characterization of the railroad traffic with using the B-WIM technique

2015 ◽  
Vol 8 (4) ◽  
pp. 491-506
Author(s):  
J. A. DE CARVALHO NETO ◽  
L. A. C. M. VELOSO
Keyword(s):  
Finite Elements ◽  
Constitutive Equation ◽  
Moving Load ◽  
Dynamic Effect ◽  
Weigh In Motion ◽  
Bridge Weigh In Motion ◽  
The One ◽  
Definition Of

AbstractThe knowledge on the active moving load of a bridge is crucial for the achievement of the information on the behavior of the structure, and thus foresee maintenance, repairs and better definition of the logistics of its active vehicles. This paper presents the development of the algorithms for the application of the Bridge-Weigh In Motion (B-WIM) method created by Moses for the weighing of trains during motion and also for the characterization of the rail traffic, allowing the obtainment of information like passage's train velocity and number and spacing of axles, eliminating the dynamic effect. There were implemented algorithms for the determination of the data referring to the geometry of the train and its loads, which were evaluated using a theoretical example, in which it was simulated the passage of the train over a bridge and the loads of its axles were determined with one hundred percent of precision. In addition, it was made a numerical example in finite elements of a reinforced concrete viaduct from the Carajás' Railroad, in which the developed system reached great results on the characterization and weighing of the locomotive when the constitutive equation of the Brazilian Standards was substituted by the one proposed by Collins and Mitchell.

scholarly journals A Nonlinear Model for Prediction of Dynamic Coefficients in a Hydrodynamic Journal Bearing

2004 ◽  
Vol 10 (6) ◽  
pp. 507-513 ◽  
Author(s):  
Jerzy T. Sawicki ◽  
T. V. V. L. N. Rao
Keyword(s):  
Equilibrium Position ◽  
Nonlinear Dynamic ◽  
Static Pressure ◽  
Journal Bearing ◽  
Dynamic Pressure ◽  
Higher Order ◽  
Pressure Gradients ◽  
Damping Coefficients ◽  
Dynamic Coefficients ◽  
Stiffness And Damping

This paper investigates the variation of nonlinear stiffness and damping coefficients in a journal orbit with respect to equilibrium position. The journal orbit is obtained by the combined solution of equations of motion and Reynolds equation. In the linearized dynamic analysis, dynamic pressure is written as a perturbation of static pressure and pressure gradients at equilibrium position. However, in order to obtain nonlinear dynamic coefficients about equilibrium position, the dynamic pressure gradients in the orbit are also written as the first order perturbation of static pressure gradients and higher order pressure gradients for displacement and velocity perturbations. The dynamic coefficients are functions of bearing displacement and velocity perturbations. The higher order pressure gradients at equilibrium position are evaluated at various eccentricity ratios and L/D ratios of 0.5 and 1.0. The variation of nonlinear dynamic coefficients is analyzed for three Sommerfeld numbers of a two-axial groove journal bearing under the action of an external synchronous load along and perpendicular to the radial journal load. Results indicate that the oil film nonlinearities affect the journal motion at lower eccentricity ratios (higher Sommerfeld numbers) with wide variation in stiffness and damping coefficients.

Dynamic Characteristics of Sealed Squeeze Film Damper With a Central Feeding Groove

2005 ◽  
Vol 127 (1) ◽  
pp. 103-111 ◽  
Author(s):  
Keun-Joo Kim ◽  
Chong-Won Lee
Keyword(s):  
Dynamic Characteristics ◽  
Pressure Field ◽  
Dynamic Pressure ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Field Analysis ◽  
Squeeze Film ◽  
Test Rig ◽  
Squeeze Film Damper ◽  
Dynamic Coefficients

In this paper, the dynamic characteristics of an oil-lubricated, sealed squeeze film damper (SFD) with a central feeding groove are analytically derived based on an enhanced dynamic pressure field analysis, accounting for the effect of the seal and feeding grooves, and its validity is experimentally verified. A test rig using an active magnetic bearing system as an exciter is introduced to identify the dynamic characteristics of SFDs with high accuracy and efficiency. Experiments are conducted with the seal gap varied, in order to investigate its effect on the dynamic characteristics of the SFD. The estimated and analytical damping and inertia coefficients for the sealed SFD with a groove are compared and it is found that the pressure field analysis, when neglecting the effect of the seal groove, tends to far underestimate the SFD dynamic coefficients.

scholarly journals EXPERIMENTAL RESEARCH ON THE DISTRIBUTION DYNAMIC PRESSURE OF THE CIRCULATION MOVEMENT OF THE WORKING ENVIRONMENT IN TOROIDAL MOBILE CONTAINERS

2019 ◽  
pp. 33-44 ◽  
Author(s):  
Leonid Yaroshenko
Keyword(s):  
Dynamic Pressure ◽  
Outer Cylinder ◽  
Practical Interest ◽  
Dynamic Effect ◽  
Absolute Magnitude ◽  
Working Environment ◽  
Working Surface ◽  
Working Medium ◽  
Electromechanical Drive ◽  
Bulk Medium

In the operation of vibrating process machines for machining parts with a bulk working medium in a vibrating container, individual particles of this medium carry out a chaotic movement, and the whole mass of the bulk medium performs a circulatory motion that has a dynamic effect on the surface of the workpiece in the form of the total impact of many micro-impact parts. However, the velocity of movement and the dynamic impact of the particles of the working medium are not the same in different zones of the container. The distribution of the dynamic pressure of the circulating motion of the working medium in the vibrating toroidal containers is of considerable practical interest in the development of the structures of such vibrating machines and the technological processes of their operation. The distribution of the dynamic pressure of the working environment during the intersection of the toroidal container of vibrating technological machines with electromechanical drive and vertical unbalance shaft is experimentally investigated, which allows us to determine the most advantageous locations of the work pieces during their vibration treatment based on the conditions of efficiency and processing quality as well as maximum utilization of the kinetic energy of the circulating traffic of working environment when using it for additional forced movement on work pieces. Circulating movement creates the greatest dynamic pressure in the lower zones of the container, and as the distance from the surface of the container increases - dynamic pressure gradually decreases. The magnitude and nature of the distribution of the dynamic pressure of the working environment are also influenced by the direction of its circulation. When pressed by circulating movement of the environment to the outer cylinder of the working surface, ie to the points of the surface of the container having a large amplitude of vertical oscillations, the zone with high dynamic pressure is greater than in the case pressing it the inner cylinder of the working surface of the topper, that is, to the surface points of the container that have a smaller amplitude of vertical oscillations, thus reducing the absolute magnitude of the pressure.

scholarly journals Возбуждение и регистрация нелинейного резонанса колебаний пружинного маятника с использованием электромагнитной индукции

2020 ◽  
Vol 90 (1) ◽  
pp. 5
Author(s):  
И.С. Зейликович ◽  
А.В. Никитин ◽  
А.Е. Василевич
Keyword(s):  
Numerical Simulation ◽  
Theoretical Model ◽  
Analytical Solution ◽  
Electromagnetic Induction ◽  
Nonlinear Oscillations ◽  
Nonlinear Effects ◽  
Oscillatory System ◽  
Experimental Results ◽  
Induction Method ◽  
Simulation Results

The nonlinear oscillations and resonances of the spring pendulum are experimentally and theoretically investigated. A unified by electromagnetic induction method of excitation, dissipation and registration of nonlinear oscillations is proposed. Experimental results demonstrate typical nonlinear effects, such as nonisochronism and bistability of vibrations. A theoretical model of the oscillatory system, leading to the Duffing equation, is proposed, an analytical solution and numerical simulation results are given, which agree well with the experiment.

scholarly journals A wind effect of neutron component of cosmic rays at Antarctic station “Mirny”

2016 ◽  
Vol 2 (1) ◽  
pp. 71-75
Author(s):  
Павел Кобелев ◽  
Pavel Kobelev ◽  
Артем Абунин ◽  
Artem Abunin ◽  
Мария Абунина ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
High Latitude ◽  
Dynamic Pressure ◽  
Dynamic Effect ◽  
Wind Effect ◽  
High Mountain ◽  
Hourly Data ◽  
Neutron Component ◽  
Continue Monitoring ◽  
Barometric Coefficient

Estimation of barometric coefficient for neutron component of cosmic rays was performed for Antarctic station Mirny taking into account effect of dynamic pressure caused by wind in the atmosphere. Hourly data of continue monitoring of neutron component and data of the local meteo station have been used for the period 2007-2014. Wind velocity at the observatory Mirny reaches 20-40 m/s in winter that corresponds to dynamic pressure of 5-6 mb and leads to the error of 5% in variations of neutron component because of dynamic effect in the atmosphere. The results are interesting for high latitude and high mountain detectors, where affect Bernulli may be significant.

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