scholarly journals Analysis of Dynamic Parameters of a Linear Positioning Table System

Mechanika ◽  
2020 ◽  
Vol 26 (5) ◽  
pp. 426-434
Author(s):  
Vytautas TURLA ◽  
Artūras KILIKEVICIUS ◽  
Mindaugas JUREVICIUS ◽  
Antanas FURSENKO ◽  
Kristina KILIKEVICIENE ◽  
...  
Keyword(s):  
Fixed Points ◽  
Time Scale ◽  
Dynamic Parameters ◽  
Vibration Intensity ◽  
Covariance Functions ◽  
Cross Covariance ◽  
Auto Covariance

In the paper, the spread of intensity of linear positioning table system vibrations is examined and an analysis of their parameters upon applying the theory of covariance functions is carried out. For the investigation, two linear positioning tables were chosen; for them, different lubricants were used: universal lubricant Loctite 8103 and lubricant Braycote 601EF for working in vacuum. The results of measurements of the vibration intensity in four fixed points upon varying the speed of the carriage were recorded on the time scale in form of arrays (matrices). The estimates of cross-covariance functions of the arrays of results of measurements of the digital vibration intensity were calculated. The estimates of auto-covariance functions of single arrays upon changing the quantization interval on the time scale were calculated too. For the calculations, the software developed upon using Matlab7 package of procedures was applied.

scholarly journals Analysis of Dynamic Parameters of a Railway Bridge

2019 ◽  
Vol 9 (12) ◽  
pp. 2545 ◽  
Author(s):  
Artūras Kilikevičius ◽  
Jonas Skeivalas ◽  
Kristina Kilikevičienė ◽  
Jonas Matijošius
Keyword(s):  
Fixed Points ◽  
Time Scale ◽  
Modal Parameters ◽  
Dynamic Parameters ◽  
Railway Bridge ◽  
Covariance Functions ◽  
The Individual ◽  
The Impact ◽  
Auto Covariance

This article analyses the dispersion of vibration accelerations of a railway bridge during the passage of a train, and presents an analysis of their parameters after the application of the theory of covariance functions. The measurements of vibration accelerations at the fixed points of the beams of the overlay of the bridge were recorded in the time scale as digital arrays (matrices). The values of inter-covariance functions of the arrays of data of measurements of digital vibration accelerations and the values of auto-covariance functions of the individual arrays, changing the quantization interval in the time scale, were calculated. The compiled software Matlab 7 in the operator package environment was used in calculations. This article aims at determining the interdependencies of results of vibrations of bridge points rather than at the impact which a train makes on a bridge without emphasizing the modal parameters of the bridge. The aforementioned interdependencies make it possible to predict the results of hard-to-reach points.

scholarly journals Theoretical and experimental analysis of dynamic parameters of the leveling and centering device

2019 ◽  
Vol 52 (3-4) ◽  
pp. 222-228
Author(s):  
Arturas Kilikevicius ◽  
Jonas Skeivalas ◽  
Mindaugas Jurevicius ◽  
Kristina Kilikeviciene ◽  
Vytautas Turla ◽  
...  
Keyword(s):  
Time Scale ◽  
Measurement Techniques ◽  
Measurement Data ◽  
Covariance Functions ◽  
Cross Covariance ◽  
Measurement Results ◽  
Dynamical Parameters ◽  
Oscillation Strength ◽  
Special Computer Program ◽  
Auto Covariance

The article analyzes vibrational oscillation’s strength dissemination and the parameters in the centering and leveling table using the covariance function theory. The implementation of measurement techniques requires to use most advanced ideas, and to seek and develop new tools, based on which the direction of angle calibration system’s development could be substantiated and calibration methodologies could be enabled. Vibrational oscillation strength measurements across fixed five ring points’ observations were recorded on a time scale in five vectors arrays (matrices). The covariance functions have enabled the evaluation of the influence of the vibrations of the corresponding rings on the accuracy of the measurement results. Expressions of auto-covariance and cross-covariance functions show the changes in the time scale of the interdependence between the parameters of the corresponding vibrations of the rings on the smoothing device. These changes significantly affect the measurement data errors. The digital vibrational strength measurement arrays’ reciprocal covariance functions were calculated, and estimates of individual arrays’ auto-covariance functions, by changing the quantization interval on the time scale. The covariance model proposed by the authors for the analysis of the dynamical parameters of the centering–leveling devices can be used to investigate the dynamic characteristics of the angular comparators containing the said devices and at the same time to determine the ways of improving the precision of these angular comparators. The calculations were carried out using the special computer program developed by the authors of the Matlab7 Operator Package (The MathWorks, Inc. R2012a 7.14.0.739 License Number 699298).

Vibration measurements of paper prints and the data analysis

2020 ◽  
Vol 35 (1) ◽  
pp. 115-123
Author(s):  
Arturas Kilikevicius ◽  
Mindaugas Jurevicius ◽  
Robertas Urbanavicius ◽  
Vytautas Turla ◽  
Kristina Kilikeviciene ◽  
...  
Keyword(s):  
Time Scale ◽  
Practical Problem ◽  
Mechanical Parameters ◽  
Paper Sheet ◽  
Correct Position ◽  
Vibration Signals ◽  
Covariance Functions ◽  
Cross Covariance ◽  
Auto Covariance ◽  
Printing Machine

AbstractThis paper discusses about the scatter of the intensity of vibration signals of paper prints and analyses their mechanical parameters applying the theory of covariance functions. It is an important practical problem, before starting printing process of colour prints, expecting the correct position of fixed raster points, to adjust the paper sheet tension between printing machine sections. The results of measuring the intensity of vibration signals at the fixed points were presented on a time scale in the form of arrays (matrices). The estimates of cross-covariance functions between digital arrays result in measuring the intensity of vibrations, and the estimates of auto-covariance functions of single arrays were calculated upon changing the quantization interval on the time scale. Application of normed auto-covariance and cross-covariance functions enables reduction of preprinting experimental measurements, which saves time (what is actual for industry). Tension force depends on the mechanical properties of the paper sheet and print. These characteristics depend on paper type, layers of printing colors and positioning of the coverage. In the calculation, the software Matlab 7 in batch statement environment was applied.

scholarly journals Analysis of Air Pollution Parameters Using Covariance Function Theory

2020 ◽  
Vol 27 (4) ◽  
pp. 555-565
Author(s):  
Ignas Daugela ◽  
Jurate Suziedelyte Visockiene ◽  
Jonas Skeivalas
Keyword(s):  
Environmental Pollution ◽  
Time Scale ◽  
Covariance Function ◽  
Function Theory ◽  
Trace Gas ◽  
Covariance Functions ◽  
Intensity Changes ◽  
Oxygen Gas ◽  
Auto Covariance ◽  
Sentinel 2

Abstract The paper analyses the intensity changes of three pollution parameter vectors in space and time. The RGB raster pollution data of the Lithuanian territory used for the research were prepared according to the digital images of the Sentinel-2 Earth satellites. The numerical vectors of environmental pollution parameters CH4 (methane), NO2 (nitrogen dioxide) and for direct comparison O2 (oxygen gas) were used for the calculations. The covariance function theory was used to perform the analysis of intensity changes in digital vectors. Estimates of the covariance functions of the numerical vectors of pollution parameters and O2 or the auto-covariance functions of single vectors are calculated from random functions consisting of arrays of measurement parameters of all parameters vectors. Correlation between parameters vectors depends on the density of parameters and their structure. Estimates of covariance functions were calculated by changing the quantization interval on a time scale and using a compiled computer program using the Matlab procedure package. The probability dependence between the environmental pollution parameter vectors and trace gas of the territory in Lithuania and their change in time scale was determined.

scholarly journals Analysis of Dynamic Parameters of the System of Raster Formation and Control

2020 ◽  
Vol 22 (3) ◽  
pp. 78-88
Author(s):  
Antanas Fursenko ◽  
Arturas Kilikevicius ◽  
Kristina Kilikeviciene ◽  
Jonas Skeivalas ◽  
Albinas Kasparaitis ◽  
...  
Keyword(s):  
Time Scale ◽  
Measuring Equipment ◽  
Research Work ◽  
Measurement Data ◽  
Covariance Functions ◽  
Sensing System ◽  
Position Detection ◽  
Optical Measuring ◽  
And Control ◽  
Auto Covariance

The presented research work analyzes the sensing system, the main aim of which is a raster formation and controlling this process using the optical measuring equipment and high precision angle encoders. Optical measuring equipment are used for the raster position detection, meanwhile angle encoders for controlling the tape speed. The main parameter of raster formation process is fixed transportation speed, but there are difficulties to realize it, because there is imperfection of the device elements. The article analyzes the dispersion of vibration accelerations of the raster formation device and tape in the two directions (transverse and longitudinal) and presents an analysis of their parameters in application of the theory of covariance functions. The results of the measurements of vibration accelerations at the fixed points of the device constructions and the tape were recorded on a time scale in the form of digital arrays (matrices). Values of auto-covariance and inter-covariance functions of digital arrays of the vibration accelerations measurement data were calculated by changing the quantum interval in a time scale. The developed software Matlab 7 in operator package environment was used in the calculations.

scholarly journals The Analysis of Vibration Signals of Critical Points of the Bus Body Frame

2019 ◽  
Vol 48 (3) ◽  
pp. 296-304 ◽  
Author(s):  
Artūras Kilikevičius ◽  
Kristina Kilikevičienė ◽  
Antanas Fursenko ◽  
Jonas Matijošius
Keyword(s):  
Fixed Points ◽  
Critical Points ◽  
Time Scale ◽  
Analysis Software ◽  
Body Frame ◽  
Vibration Signals ◽  
Mechanical Structure ◽  
Covariance Functions ◽  
Wave Distribution ◽  
Bus Body

In this paper, authors have investigated wave distribution caused by the mechanical structure of a passenger bus body frame and its parameters based on the theory of covariance functions. Authors have measured the intensity of vibrations at fixed points. Time scale analyses were conducted based on data arrays (matrixes). The estimates of covariance functions clearly showed that changes in the state of the bus mechanical structure invariably impact changes of the intensity of vibration signals at the relevant points. In the analysis, software Matlab 7 was applied.

Matérn Cross-Covariance Functions for Multivariate Random Fields

2010 ◽  
Vol 105 (491) ◽  
pp. 1167-1177 ◽  
Author(s):  
Tilmann Gneiting ◽  
William Kleiber ◽  
Martin Schlather
Keyword(s):  
Random Fields ◽  
Covariance Functions ◽  
Cross Covariance

scholarly journals Analysis of parameters of railway bridge vibration caused by moving rail vehicles

2019 ◽  
Vol 52 (9-10) ◽  
pp. 1210-1219 ◽  
Author(s):  
Arturas Kilikevicius ◽  
Antanas Fursenko ◽  
Mindaugas Jurevicius ◽  
Kristina Kilikeviciene ◽  
Gintautas Bureika
Keyword(s):  
Function Method ◽  
Dynamic Loads ◽  
Railway Bridge ◽  
Vibration Signals ◽  
Railway Bridges ◽  
Covariance Functions ◽  
Rail Vehicles ◽  
Measurement Results ◽  
Static And Dynamic Loads ◽  
Auto Covariance

The durability and endurance of the exploitation of railway bridges depend on the intensity and the manner of the static and dynamic loads affecting them. Heavy freight trains passing the bridges cause huge vertical and dual-axis vibrations, which are evidenced by the fatigue of the construction of the bridge. The scatter of the acceleration intensity of the railway bridge vibratory oscillation and their parameters are analysed while applying the theory of covariation functions. The results of the measurements of the intensity of the acceleration of vibratory oscillation in the points of support beams recorded in the timescale in the form of arrays (matrixes). Applied covariance function method provides measurement equipment and experimental simplicity of the analysis of the railway bridge vibration signals. The standard scores of mutual covariation functions of the array of the measurement results of the acceleration of digital vibratory oscillation and the standard scores of the auto-covariance functions of separate arrays are altering considering the interval of quantization in the timescale. Results gained by analysis prove the advantage of the rationed auto-covariational functions method while analysing the dynamic oscillation of bridges.

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