Method for increasing the speed of an electrodynamic shaker for vibration test of rolling stock equipment

2021 ◽  
pp. 107754632110466
Author(s):  
Peng Wang ◽  
Hua Deng ◽  
Yue Liu ◽  
Yi-ming Wang ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Input Impedance ◽  
Vertical Direction ◽  
Maximum Velocity ◽  
Rolling Stock ◽  
Vibration Test ◽  
Vibration Testing ◽  
High Frequencies ◽  
Electrodynamic Shaker ◽  
Long Life ◽  
The Impact

The velocity required in IEC 61373 for long-life random vibration testing of Category-3 rolling stock equipment in the vertical direction is 2.7821 m/s, but the maximum velocity of existing electrodynamic shakers falls in the range of 2–2.5 m/s. In this study, an electrodynamic shaker with a velocity satisfying the requirements for vibration testing of Category-3 rolling stock equipment was developed. First, mechanical and equivalent circuit models of an electrodynamic shaker were developed. On this basis, reducing the impedance of the armature coil was identified as the best option for increasing the velocity of the shaker. However, owing to the impact of the back electromotive force of the armature coil, a decrease in the input impedance of the armature coil at low frequencies leads to an increase in its input impedance at high frequencies. To reduce the input impedance at high frequencies, a shading coil was incorporated into the circuit. The shading coil-incorporated new design was modeled using equivalent circuits and simulated numerically. The results showed that the improvement measures—incorporating a shading coil, increasing the cross-sectional area, and reducing the number of turns of the armature coil—effectively reduced the input impedance of the armature coil, thereby increasing the armature coil current and the velocity of the shaker. Finally, a shaker with a maximum velocity of 3.2 m/s was fabricated based on the new design and was validated to satisfy the high-velocity requirement for the long-life vibration test of Category-3 equipment in the vertical direction as specified in IEC 61373.

scholarly journals The development of diagnostics methodological principles of the railway rolling stock on the basis of the analysis of dynamic vibration processes of the rail

2018 ◽  
Vol 157 ◽  
pp. 03007 ◽  
Author(s):  
Juraj Gerlici ◽  
Olena Nozhenko ◽  
Ganna Cherniak ◽  
Mykola Gorbunov ◽  
Rostyslav Domin ◽  
...  
Keyword(s):  
Vertical Direction ◽  
Theoretical Research ◽  
Rolling Stock ◽  
Experimental Data Processing ◽  
Methodology Development ◽  
Additional Information ◽  
Dynamic Vibration ◽  
Train Speed ◽  
Methodological Principles ◽  
The Impact

The paper discusses the preconditions of the methodology development of diagnosis system for assessing dynamic impact of the rolling stock on the basis of processing and analysis of data obtained in operation on the results of measurement of parameters that characterize dynamic vibration processes of the mechanical system of “rolling stock – track”. On the basis of usage of the processing methods of time series and stochastic processes there has been established the relationship between these dynamic processes and wheel defects, and designed experimental data processing algorithms, which in the future will be an integral part of the intellectual systems of decision making when assessing the impact level of the rolling stock on the track. The article presents some results of the experimental and theoretical research of the rail accelerations data, which have been registered during passing of the train. The computational algorithm of the specialized pre-processing of the multidimensional signal recorded by this system is described. The advantage of this algorithm is that it does not require additional information about the train speed on the section equipped with the monitoring system, about the number of wheel pairs of locomotives and train cars, and about the distances between the wheel pairs. Based on the processing results of accelerations of the rails there have been set the parameters of increase in all statistical indicators with increase in the train speed. It is noted that the level of indicators for accelerations of the rails in the vertical direction is twice as high as the corresponding parameters in the horizontal direction.

scholarly journals A next step in disruption management: combining operations research and complexity science

2021 ◽  
Author(s):  
Mark M. Dekker ◽  
Rolf N. van Lieshout ◽  
Robin C. Ball ◽  
Paul C. Bouman ◽  
Stefan C. Dekker ◽  
...  
Keyword(s):  
Operations Research ◽  
Complexity Science ◽  
Rolling Stock ◽  
Accurate Information ◽  
Disruption Management ◽  
Railway Systems ◽  
Decentralized Decision Making ◽  
Control Situations ◽  
Management Techniques ◽  
The Impact

AbstractRailway systems occasionally get into a state of being out-of-control, meaning that barely any train is running, even though the required resources (infrastructure, rolling stock and crew) are available. Because of the large number of affected resources and the absence of detailed, timely and accurate information, currently existing disruption management techniques cannot be applied in out-of-control situations. Most of the contemporary approaches assume that there is only one single disruption with a known duration, that all information about the resources is available, and that all stakeholders in the operations act as expected. Another limitation is the lack of knowledge about why and how disruptions accumulate and whether this process can be predicted. To tackle these problems, we develop a multidisciplinary framework combining techniques from complexity science and operations research, aiming at reducing the impact of these situations and—if possible—avoiding them. The key elements of this framework are (i) the generation of early warning signals for out-of-control situations, (ii) isolating a specific region such that delay stops propagating, and (iii) the application of decentralized decision making, more suited for information-sparse out-of-control situations.

scholarly journals Latent Heat Thermal Storage of Nano-Enhanced Phase Change Material Filled by Copper Foam with Linear Porosity Variation in Vertical Direction

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1508
Author(s):  
Mohammad Ghalambaz ◽  
Mohammad Shahabadi ◽  
S. A. M Mehryan ◽  
Mikhail Sheremet ◽  
Obai Younis ◽  
...  
Keyword(s):  
Natural Convection ◽  
Phase Change ◽  
Phase Change Material ◽  
Metal Foam ◽  
Vertical Direction ◽  
Melting Time ◽  
Copper Foam ◽  
Average Porosity ◽  
The Impact ◽  
Change Material

The melting flow and heat transfer of copper-oxide coconut oil in thermal energy storage filled with a nonlinear copper metal foam are addressed. The porosity of the copper foam changes linearly from bottom to top. The phase change material (PCM) is filled into the metal foam pores, which form a composite PCM. The natural convection effect is also taken into account. The effect of average porosity; porosity distribution; pore size density; the inclination angle of enclosure; and nanoparticles’ concentration on the isotherms, melting maps, and the melting rate are investigated. The results show that the average porosity is the most important parameter on the melting behavior. The variation in porosity from 0.825 to 0.9 changes the melting time by about 116%. The natural convection flows are weak in the metal foam, and hence, the impact of each of the other parameters on the melting time is insignificant (less than 5%).

VERY HIGH-ORDER SPATIALLY IMPLICIT SCHEMES FOR COMPUTATIONAL ACOUSTICS ON CURVILINEAR MESHES

2001 ◽  
Vol 09 (04) ◽  
pp. 1259-1286 ◽  
Author(s):  
MIGUEL R. VISBAL ◽  
DATTA V. GAITONDE
Keyword(s):  
Three Dimensional ◽  
Radiation Condition ◽  
Higher Order ◽  
High Order ◽  
High Frequencies ◽  
Decomposition Strategies ◽  
The Impact ◽  
Spurious Modes ◽  
Very High ◽  
Computational Strategy

A high-order compact-differencing and filtering algorithm, coupled with the classical fourth-order Runge–Kutta scheme, is developed and implemented to simulate aeroacoustic phenomena on curvilinear geometries. Several issues pertinent to the use of such schemes are addressed. The impact of mesh stretching in the generation of high-frequency spurious modes is examined and the need for a discriminating higher-order filter procedure is established and resolved. The incorporation of these filtering techniques also permits a robust treatment of outflow radiation condition by taking advantage of energy transfer to high-frequencies caused by rapid mesh stretching. For conditions on the scatterer, higher-order one-sided filter treatments are shown to be superior in terms of accuracy and stability compared to standard explicit variations. Computations demonstrate that these algorithmic components are also crucial to the success of interface treatments created in multi-domain and domain-decomposition strategies. For three-dimensional computations, special metric relations are employed to assure the fidelity of the scheme in highly curvilinear meshes. A variety of problems, including several benchmark computations, demonstrate the success of the overall computational strategy.

An Investigation of the Vibration Testing Method for Small Diameter Endmills

2014 ◽  
Vol 625 ◽  
pp. 134-139
Author(s):  
Takenori Ono
Keyword(s):  
Small Diameter ◽  
Milling Process ◽  
Modal Parameters ◽  
Vibration Testing ◽  
Function Generator ◽  
Testing Method ◽  
Milling Tool ◽  
Compliance Curve ◽  
Vibration Tests ◽  
The Impact

This paper introduced about the in-process vibration testing method for small diameter endmill. By this method, the natural frequency and modal parameters such as mass, damping, and stiffness of the milling tool can be determined in the milling process. An oscillation of the vibrator is controlled by the function generator to apply the impact force at the appropriate cutting period. The measurement setup can determine the compliance curve by the measurement signals of the exiting force and tool deformation. To evaluate the feasibility of the new method, vibration tests were performed on a square endmill which has the diameter of 4 mm in the milling on brass material. Results of vibration tests show that modal parameters of the specific vibration mode can be determined by the new developed method.

scholarly journals Metallic conduction through van der Waals interfaces in ultrathin $$\hbox{Bi}_2\hbox{Te}_3$$ films

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shinichiro Hatta ◽  
Ko Obayashi ◽  
Hiroshi Okuyama ◽  
Tetsuya Aruga
Keyword(s):  
Photoelectron Spectroscopy ◽  
Van Der Waals ◽  
Vertical Direction ◽  
Conductivity Measurement ◽  
Spatial Separation ◽  
Mean Free Path ◽  
Conduction Path ◽  
Conductivity Increase ◽  
The Impact

AbstractWhile the van der Waals (vdW) interface in layered materials hinders the transport of charge carriers in the vertical direction, it serves a good horizontal conduction path. We have investigated electrical conduction of few quintuple-layer (QL) $$\hbox {Bi}_2\hbox {Te}_3$$ Bi 2 Te 3 films by in situ four-point probe conductivity measurement. The impact of the vdW (Te–Te) interface appeared as a large conductivity increase with increasing thickness from 1 to 2 QL. Angle-resolved photoelectron spectroscopy and first-principles calculations reveal the confinement of bulk-like conduction band (CB) state into the vdW interface. Our analysis based on the Boltzmann equation showed that the conduction of the CB has a long mean free path compared to the surface-state conduction. This is mainly attributed to the spatial separation of the CB electrons and the donor defects located at the Bi sites.

Impact of Technology Infusion on System Complexity and Modularity

2015 ◽  
Author(s):  
GwangKi Min ◽  
Eun Suk Suh ◽  
Katja Hölttä-Otto
Keyword(s):  
System Performance ◽  
New Technologies ◽  
Life Cycles ◽  
System Complexity ◽  
Host System ◽  
Technology Infusion ◽  
Long Life ◽  
Impact Of Technology ◽  
The Impact ◽  
Over Time

Complex systems often have long life cycles with requirements that are likely to change over time. Therefore, it is important to be able to adapt the system accordingly over time. This is often accomplished by infusing new technologies into the host system in order to update or improve overall system performance. However, technology infusion often results in a disruption in the host system. This can take the form of a system redesign or a change in the inherent attributes of the system. In this study, we analyzed the impact of technology infusion on system attributes, specifically the complexity and modularity. Two different systems that were infused with new technologies were analyzed for changes in complexity and modularity.

Shrinking metropolitan area: Costly homeownership and slow spatial shrinkage

Urban Studies ◽  
2017 ◽  
Vol 56 (6) ◽  
pp. 1113-1128 ◽  
Author(s):  
Masatomo Suzuki ◽  
Yasushi Asami
Keyword(s):  
Land Use ◽  
Simple Model ◽  
Social Welfare ◽  
Metropolitan Area ◽  
Population Decline ◽  
Life Quality ◽  
Long Life ◽  
New Residents ◽  
The Government ◽  
The Impact

With a simple model of land use and market arbitrage, this paper investigates the impact of population decline – when existing homeowners compete to attract a small number of new residents – on homeownership and land use. We show that, if a strictly positive cost is required for ownership abandonment, selling used houses is impossible in the periphery, while leasing is possible. We also show that only long-life-quality houses, which require a larger initial investment and sustain greater utility for longer than conventional ones, attract new residents to the periphery. Social welfare may decrease, because the government has to maintain the slowly shrinking, less densely inhabited urban area.

scholarly journals Turbulence coherence and its impact on wind-farm power fluctuations

2018 ◽  
Vol 855 ◽  
pp. 1116-1129 ◽  
Author(s):  
Nicolas Tobin ◽  
Leonardo P. Chamorro
Keyword(s):  
Power Spectrum ◽  
Atmospheric Turbulence ◽  
Turbulent Diffusion ◽  
Wind Farm ◽  
Spectral Characteristics ◽  
Wind Farms ◽  
High Frequencies ◽  
Power Fluctuations ◽  
The Impact ◽  
Coherence Spectrum

Using a physics-based approach, we infer the impact of the coherence of atmospheric turbulence on the power fluctuations of wind farms. Application of the random-sweeping hypothesis reveals correlations characterized by advection and turbulent diffusion of coherent motions. Those contribute to local peaks and troughs in the power spectrum of the combined units at frequencies corresponding to the advection time between turbines, which diminish in magnitude at high frequencies. Experimental inspection supports the results from the random-sweeping hypothesis in predicting spectral characteristics, although the magnitude of the coherence spectrum appears to be over-predicted. This deviation is attributed to the presence of turbine wakes, and appears to be a function of the turbulence approaching the first turbine in a pair.

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.

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