Wyniki wyszukiwania - BazTech

1

Challenges in assessing the vibrations influence on people in buildings using non-contact measurements

Bróż Natalia, Nazarko Piotr

Czasopismo Inżynierii Lądowej, Środowiska i Architektury / Journal of Civil Engineering, Environment and Architecture

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2023

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Vol. 70

51--64

EN

This research article presents a comparative analysis of vibration assessments in lecture halls to investigate their influence on people using contact (accelerometers) and non-contact (laser vibrometers) measurement techniques. The study aims to verify the accuracy and reliability of vibration analysis in relation to two approaches and determined physical parameters, i.e. acceleration amplitudes and vibration velocities. The intriguing fact was that none of the building users reported any perceived discomfort from vibrations, despite the determined parameters of the signal measured using a laser vibrometer indicating exceedance of permissible vibration amplitudes in several frequency bands. The conducted comparative analysis leads to the conclusion that the location of the laser head tripod on the vibrating floor introduces significant vibration amplification, which in turn may lead to an incorrect assessment of the impact of vibrations on people in buildings. The studies described in the article were carried out in accordance with the procedure contained in the Polish national standard PN-B-02171. The obtained results and the resulting conclusions are an important contribution to a better understanding of the advantages and limitations resulting from the use of non-contact measurements.

2

Principles of piezo-based machinery health monitoring

Ostachowicz W., Wandowski T., Malinowski P.

Transactions of the Institute of Fluid-Flow Machinery

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2015

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nr 127

117--136

EN

In this paper methods used for structural health monitoring of machinery parts are discussed. These methods are based on applications of piezoelectric transducers. Proposed methods are used for assessment of structural machine parts manufactured of carbon fiber reinforced plastics/polymers (CFRP) and glass fiber reinforced plastics/polymers (GFRP). The first discussed method is based on elastic wave propagation and scanning laser vibrometry. This method is based on the fact that any kind of structural discontinuities cause changes in elastic wave propagation within the structure. In the proposed approach elastic waves are generated using piezoelectric transducer and then the waves are registered using scanning laser vibrometer. Here attention was paid on an analysis of elastic wave propagation in simple composite parts and parts with complex structure. The paper presents also results of simulated damage localization. The second method is an electromechanical impedance (EMI) technique. In this case piezoelectric transducer is also effectively used. This transducer is attached to an investigated structure. Due to electromechanical coupling of piezoelectric transducer and a structure, characteristics of mechanical resonances of the structure can be registered through the measurement of electrical parameters of piezoelectric transducer. An initiation of damage causes changes in resonant characteristics of considered structures. As electrical parameter very often impedance, admittance, resistance, conductance or reactance are used. For that purpose electrical impedance analyzer is used. Three parameters have been taken for the analysis. For proposed method effective damage indexes have been proposed.

3

Problems of in-situ vibroacoustic testing of low-vibroactive devices

Barczewski R., Jakubek B.

Vibrations in Physical Systems

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2012

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Vol. 25

59--64

EN

This paper article outlines the problems of in situ vibroacoustic testing of low-vibroactive devices. Moreover a comparison of selected methods of object's surface velocity mapping was carried out in the paper. Primary features, advantages and limitations of these methods are stated here. On the example of tests on a refrigerator the methodology and specifics of testing of this type of devices using a laser vibrometer is also shown.

4

Dopplerowska wibrometria laserowa w diagnostyce silnika spalinowego

Kaźmierczak A., Krakowian K., Wróbel R.

Przegląd Elektrotechniczny

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2010

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R. 86, nr 10

147-149

PL

Artykuł prezentuje możliwości zastosowania systemów diagnostycznych, opartych na dopplerowskim laserze wibrometrycznym i cyfrowym przetwarzaniu sygnału prędkości drgań silnika spalinowego o zapłonie samoczynnym. Badano jednostkę napędową – silnik Volkswagen 1,9 tdi, montowany w szeregu popularnych na polskich drogach pojazdów samochodowych. Przedstawiona w artykule analiza wyników pomiaru opiera się na porównaniu prędkości względnej drgań silnika sprawnego z tym samym obiektem po uszkodzeniu układu zasilania. Prędkość względną drgań, będącą funkcją dyskretną, poddano operacjom cyfrowego przetwarzania, takimi jak okienkowanie i filtrowanie cyfrowe.

EN

The article presents possibilities of use popular diagnostics systems based on Doppler Laser Vibrometry and digital signal processing on discrete absolute velocity vibration signal of diesel combustion engine. Measure of the absolute velocity of engine’s vibration was carried out by Polytec PSV – 400 vibrometer. The Volkswagen 1,9 tdi diesel engine was researched. It is a very popular unit which is installed in a series of popular European vehicles. The construction of this engine is very interesting because the fuel supply system is based on injections pumps. Analysis of measured absolute vibration signal of engine which is presented in article based on a comparison between vibrations of properly working engine to this same object with fuel supply failure. Received diagnostic’s information in a voltage answer form which is proportionate to an amplitude of absolute velocity is a discrete function treated of digital signal processing with non parametrical windowing, fast Fourier transform, filtering with finite impulse response filters (which were windowing in time domain for achieved a better characteristic) generated with expanded Remez algorithm.

5

Laser scanning vibrometry applied to evaluate the quality of valve plates in LPG injection system

Łukasik B., Breaban F., Wendeker M., Boulet P.

Eksploatacja i Niezawodność

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2006

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nr 3

41-44

EN

The article presents the basics of laser vibrometry and basics of introducing LPG injection system into ordinary car engine. It also shows examples of research results conducted using laser vibrometry in order to evaluate the quality of LPG injection bus. All the measurements where taken using Polytec vibrometer and this article presents the principles of conducting research using this equipment.

6

Nowoczesne metody pomiaru drgań mechanicznych maszyn rolniczych dla potrzeb weryfikacji ich modeli analitycznych

Kromulski J.

Journal of Research and Applications in Agricultural Engineering

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2001

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Vol. 46, nr 4

32-35

PL

Przedstawiono możliwości zastosowania metod wibrometrii laserowej do wyznaczenia drgań mechanicznych maszyn rolniczych i ich elementów. Wskazano na zalety metody wibrometrii laserowej w stosunku do tradycyjnych metod pomiaru drgań mechanicznych za pomocą czujników piezoelektrycznych lub indukcyjnych. Jako przykład zastosowania metody wibrometrii laserowej w badaniach elementów maszyn rolniczych zamieszczono wyniki identyfikacji drgań mechanicznych tłumika wydechu ciągnika. Metody wibrometrii laserowej mogą być z powodzeniem zastosowane w procesie weryfikacji i doskonalenia modeli analitycznych konstrukcji (np. modeli elementów skończonych) na podstawie danych z badań eksperymentalnych.

EN

Possibilities of application of laser vibrometry methods to determining of mechanical vibrations of agricultural machines and their elements are presented in the article. Attention is pointed at advantages of the laser vibrometry method in relation to traditional methods of mechanical vibrations measurements with the use of piezoelectric or inductive sensors. As an example of application of the laser vibrometry method in agricultural machines elements tests given are in the article the results of identification of mechanical vibrations of tractor exhaust damper. Laser vibrometry methods can be successfully used in the process of verifying and optimisation of constructions analytical models (for example finite elements models) on the basis of the data obtained from experimental testing.

7

Badania charakterystyk dynamicznych zestawu: samochód "Lublin 3" - lekka naczepa, metodami wibrometrii laserowej

Kromulski J., Dubowski A.

Journal of Research and Applications in Agricultural Engineering

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2001

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Vol. 46, nr 4

27-31

PL

Przedstawiono możliwości zastosowania metod wibrometrii laserowej do identyfikacji modelu modalnego układu. Porównano wyniki identyfikacji parametrów modalnych zestawu samochód "Lublin 3" - lekka naczepa samochodowa, wyznaczone metodami wibrometrii laserowej oraz uzyskane metodami korzystającymi z piezoelektrycznych przetworników drgań. Przedstawiono zalety i ograniczenia w stosowaniu metody laserowego pomiaru odpowiedzi układu na wymuszenie. Wyniki badań identyfikacyjnych, przy użyciu wibrometrii laserowej, stwarzają szansę przyspieszenia procesów projektowania maszyn poprzez weryfikację i doskonalenie analitycznych modeli konstrukcji, na przykład komputerowych modeli uzyskanych przy użyciu metody elementów skończonych.

EN

Possibilities of application of laser vibratory methods to identification of a system modal model are presented in the article. Results of identification of modal parameters of the set: lorry "Lublin 3" and lightweight semitrailer, determined by laser vibrometry methods, with those obtained by methods using piezoelectric transducers of vibrations have been compared. Presented are also the merits and limitations occurring when using the method of laser measurement of the system response on forcing input. Results of the identification research with the use of laser vibrometry create a chance to shorten machine designing processes by verifying and optimization of the analitic construction models, for example the computer models obtained with the use of finite element method.