Wyniki wyszukiwania - BazTech

1

Selection of sound insulating elements in hydraulic excavators based onidentification of vibroacoustic energy propagation paths

Dąbrowski Z., Dziurdź J., Pakowski R.

Archives of Acoustics

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2013

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Vol. 38, No. 4

471--478

EN

In spite of the fact that standardizing operations and increased awareness of hazards led to a significant improvement of vibroacoustic climate of operator’s stands of new machines, their long-term operation - often under difficult conditions - leads to a fast degradation of acoustic qualities of machines. Temporary operations performed during surveys and periodical overhauls are rarely effective, due to the lack of any guidelines. In this situation the authors propose the algorithm for selection of eventual screens or sound absorbing and sound insulating partitions, utilizing the measuring procedure aimed at identification, at the operator’s stand, of main noise components originated from various sources. On the basis of this procedure, the vibroacoustic energy propagation paths in the machine was estimated.

2

An application of the coherence function in diagnosing marine engine injection pumps

Bejger A.

Archives of Mechanical Technology and Automation

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2012

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Vol. 32, no. 4

15--22

EN

The suitability of the coherence function for marine engine injection pump diagnostics is described. The function was used for the examination of recorded acoustic emission clastic wave signals. Characteristic frequencies from a specific fault symptom were identified. It was proved that, with known multipliers defined for each normal coordinate, the interpretation of observation resulis allows to find unknown functions of fault symptoms. In this way, we can solve a problem of identification of a mathematical model sensitive to changes in a fault parameter.

3

The coherence method of technical state evaluation combustion engine

Kałaczyński T.

Journal of KONES

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2010

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Vol. 17, No. 1

205-213

EN

The actual tendency to develop methods end techniques to diagnostic vehicles is making grow the interes f and the demand of the technical state analysis in exploration conditions, besides to systems, machines and devices more and more complex. The problem whit design and exploitation of modern machines and technical devices is to recognize the technical state in operational conditions [1-4]. To define the correct dynamic model and choose the best research method is the question of industry field, and the present paper has an approach about this topic. The coherence function which is the local measure of the similarity processes has, so the essential diagnostic properties in the reference to the objects which carry I will name linear and stationary in the field of the dynamic time. Yet the larger possibilities of uses of the diagnostic coherence functions can to find in mechanical arrangements non-stationaty or non-linear. The present methods of the diagnosing the condition of the folded objects combustion engines are which, are based on the measurements of the value steering currents. The vibrodiagnostic of combustion engines is the using analysis vibration processes generated in combustion engines the alternative method. Vibrodiagnostic enabling the opinion of the engine condition using the sensibility estimate the vibration process [l, 7-10]. The estimation of the combustion engine condition with sparkle ignition for the help of the research of vibration measures is possible thanks to utilization to the property of the coherence function [5, 6J. The implementation of software for needs: the acquisition of vibration processes, their processing, statistical inference and visualization - facilitates the leadership of investigations and the study of results.

4

Ultrasonic measurement of binocular longitudinal corneal apex movements and their correlation to cardiopulmonary system

Kowalska M. A., Kasprzak H. T., Iskander D. R.

Biocybernetics and Biomedical Engineering

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2008

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Vol. 28, no. 3

35-43

EN

The characteristics of binocular axial eye movements are of interest in studies of eye biomechanics and vision. Current techniques that are used to evaluate such movements were found to be of insufficient resolution. Here, synchronised measurements of binocular eye movements with custom designed high resolution ultrasound transducers, and cardiac electric cycle were considered. The mechanical and electrical signals were examined using spectral, time-frequency, and coherence analyses. The results showed that a close correlation and intricate phase relationships exist between longitudinal eye movements and cardiopulmonary signals. Understanding these relationships could provide a better insight on interactions between eye biomechanics and vision.

5

Zastosowanie metody nieparametrycznego wygładzania krzywych do analizy danych zmierzonych na obiekcie rzeczywistym metodą testu impulsowego

Iwaniec J.

Diagnostyka

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2005

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Vol. 34

115--120

PL

W pracy zaproponowano metodę umożliwiającą poprawianie jakości danych stanowiących podstawę do estymacji funkcji przejścia, zmierzonych metodą testu impulsowego na obiekcie rzeczywistym, dla którego nie jest możliwe poprawne wyznaczenie funkcji przejścia przy użyciu metod klasycznych ze względu na bardzo niskie wartości funkcji koherencji dla zmierzonych charakterystyk siły wymuszającej i odpowiedzi układu.

EN

In the paper there is presented the new method for quality improvement of data measured on the real object by the use of impulse test. The method makes it possible to estimate transfer functions correctly in case when classical methods fail because of very low values of coherence function for measured characteristics of exciting force and system response.

6

Separacja składowych widmowych w zadaniu identyfikacji modelu nieliniowego

Dziurdź J.

Diagnostyka

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2004

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Vol. 30, T. 1

162--166

PL

W zastosowaniach technicznych zużycie maszyny często objawia się wzrostem nieliniowości obserwowanych drgań mechanicznych (hałasu). Ponieważ efekty te przejawiają się występowa-niem w widmie ciągów poliharmonicznych o stosunkowo niskich amplitudach łatwo jest o po-myłki w interpretacji obrazów widmowych. Opracowanie przedstawia propoz.ycję metody zwięk-szenia rozdzielczości analizy widmowej przy użyciu funkcji koherencji.

EN

In many technical application during wear process of machine some nonlinear effects of vibra-tions (and noise) increase. Because this effects are usually long poliharmonic series, it is generally difficult to separate different symptoms. The paper includes a proposal of algorithm (using the co-herence function) increasing resolution of spectrum analysis to the value smaller than it is possible to achieve using Fourier transform, when the sample of satisfying duration is not possible to get.