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    Wyświetlanie 1-6 z 6
    Tytuł:
    Principles of piezo-based machinery health monitoring
    Autorzy:
    Ostachowicz, W.
    Wandowski, T.
    Malinowski, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/175452.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    laser vibrometry
    LDV
    electromechanical impedance
    EMI damage localization
    composites
    Opis:
    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.
    Źródło:
    Transactions of the Institute of Fluid-Flow Machinery; 2015, 127; 117-136
    0079-3205
    Pojawia się w:
    Transactions of the Institute of Fluid-Flow Machinery
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comparative analysis of the vibrations of a different kind of engine mounted in the same new motor vehicles
    Autorzy:
    Sitnik, L.
    Magdziak-Tokłowicz, M.
    Wróbel, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/247090.pdf
    Data publikacji:
    2011
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    laser Doppler vibrometry
    engine vibration
    vibration velocity
    Opis:
    The paper presents the results of tests carried out on two spark-ignition engines: 1.4BZ 90CV CD and 1.4BZ 120CV CD installed in new Fiat Bravo (model 198, version 54A) motor cars. The latter engine model (120CV) was equipped with a supercharging system. The research consisted in comparing engine vibrations measured in specific and representative points. In order to determine the vertical component vibrations, the measurements were performed via a mirror. A PSV-400 laser Doppler vibrometer made by Polytec was used to measure vibration velocities. The vibrometric system directly measures two quantities: displacement and velocity. In the investigated case, vibration velocity is the variable which supplies better diagnostic information. Vibrations were measured for the car standing on its wheels and for the car jacked up to reduce the influence of the car vibration damping systems on the measurement results. The latter are presented in the form of comparative diagrams. Moreover, the fast Fourier transform was used to determine the frequency distribution. Prior to that signal was subjected to conditioning operations using parametric windowing and filtering. Interesting conclusions emerge from the obtained results and on their basis the effect of the drive unit on the behaviour of the car body can be assessed for different engine types and rotational speeds. It is shown that the way in which the engine is mounted affects the vibrations of the car.
    Źródło:
    Journal of KONES; 2011, 18, 4; 443-448
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Transmission of vibrations from the engine to the car body
    Autorzy:
    Aleksieva, V.
    Valchanov, H.
    Magdziak-Tokłowicz, M.
    Wróbel, J.
    Włostowski, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/243558.pdf
    Data publikacji:
    2016
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    LDV
    laser Doppler vibrometry
    car body
    car suspension
    Opis:
    Vibrations have become an important factor of vehicles. Vibration tests help identify, and then tune the automotive vehicle to improve the structural strength. Due to the increasing development of vehicles and machines and their widespread use. Increased research-using vibrations due to their low or zero interference with the vehicle under test. Vibration testing is often carried out using Laser Doppler Vibrometry (LDV), a device that is used for contactless measurement of vibration on the surface. The laser beam is directed from the device to the surface of interest, and the amplitude and frequency of vibration are extracted from the Doppler shift frequency of the reflected laser beam due to the movement surface. High values of vibration transmitted from the engine, and the way significantly affect the body of the vehicle and the driver. Article presents results of research carried out on vehicles powered by three different engines and rpm. Tests were carried out on an engine dynamometer in the same environmental conditions. Two of engines were with spark ignition, including one with a supercharged engine and compression ignition engine. The measurements were made using the Laser Doppler Vibrometry using Fast Fourier Transform. The spectrum obtained is used for further analysis to determine the acceleration level at various frequencies. Obtained from Fast Fourier Transform readings used for drawing graphs of frequency V acceleration. The results of the study are interesting and promising, as they show a significant difference in the velocity for spark ignition engines and compression-ignition.
    Źródło:
    Journal of KONES; 2016, 23, 4; 17-23
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Vehicle vibration in human health
    Autorzy:
    Sitnik, L.J.
    Magdziak-Tokłowicz, M.
    Wróbel, R.
    Kardasz, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/242806.pdf
    Data publikacji:
    2013
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    noise and vibration
    laser Doppler vibrometry
    digital signal processing
    Opis:
    Fast development of technology over the last decades has contributed to the adverse effects that may affect human health (both physical and mental). Such negative effects may include noise and vibration. These phenomena are accompanied by most of the technological processes. Need for more efficient and productive processes is causing rising trend in intensifying of these phenomena. It is unavoidable to increase efficiency without increasing the operating speed of machinery and equipment. The main goal of this paper is to carry out NVH (noise, vibration and harshness) analysis of engines; compression-ignition engine (diesel) and spark-ignition engine (gasoline) equipped in the same type of vehicle. But purpose is laying on presented methodology, not results of researches (but of course it will be presented too) which often (mainly) is made for failure detections. This paper will also cover influence of the engine mounting on generated acoustic vibrations followed by comparative NVH analysis of states occurring in diesel and gasoline engine. Scope of the work: a) theoretical introduction, b) presentation of vibration measurement (using LDV: Laser Doppler Vibrometry), c) NVH analysis in two types of engines, d) comparison of results, e) conclusions.
    Źródło:
    Journal of KONES; 2013, 20, 4; 411-418
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The diagnosis of EGR systems failuers depended on detection and measure of vibroacustic vibrations
    Diagnostyka usterek układu EGR na podstawie detekcji i pomiarów drgań wibroakustycznych
    Autorzy:
    Kaźmierczak, A.
    Miksiewicz, K.
    Wróbel, R.
    Powiązania:
    https://bibliotekanauki.pl/articles/327690.pdf
    Data publikacji:
    2010
    Wydawca:
    Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
    Tematy:
    laserowa wibrometria Dopplerowska
    EGR
    cyfrowe przetwarzanie sygnałów
    laser Doppler vibrometry
    digital signal processing
    Opis:
    The authors presents a new in - vitro way of diagnosis in automotive vehicle which depend on detection and measure of vibroacustic vibrations of the diesel engine. It seems that the Exhaust Gas Recirculation circuit that does not work properly shouldn't have an influence on vibrations generated by an engine. However, authors indicate that this statement is wrong. EGR system has an influence on engine's vibration, what was described in the article. On that way, detection of vibrations must be accomplished with high quality diagnostic systems. Therefore, vibrometric laser scanner Polytec had been used. To achieve full diagnostic results multidimensional vibration's function has been researched, where the torque moment has been used as an extra parameter. Measured vibrations were subjected to digital signal processing like windowing, fast Fourier transform, filtration by finite impulse response which also undergone to windowing . The results of measure and processing perform in form of 3D plots, which indulge in speed estimate of the usefulness of presented method. Moreover authors presents principle of working EGRs' systems of different generations, its evolution and history. A EGR is a popular system of recirculation of the automotive vehicle emission. The principle of working depends on the forcing in the part of outlet gas to the combustion chamber. Majority of the users of automotive vehicles with EGR systems claim that system has negative effect on the performance of the car. Nonetheless that opinion is subjective, because the generally available research on the subject doesn't exist. However, EGR system, as the most of automotive vehicle is being subjected to physic's rules - it uses up. The polluted flowing valve of circuit has an influence on stability of engine's work, and what follows on a performance of a car.
    Autorzy prezentują nową metodę diagnostyczną (in-vitro), wykorzystywaną w diagnostyce pojazdów samochodowych, polegającą na detekcji i pomiarze wartości drgań o charakterze wibroakustycznym. Wydaje się, że niesprawność układu recyrkulacji spalin nie powinna mieć wpływu na drgania, generowane przez silnik spalinowy. Autorzy dowodzą, że twierdzenie taki jest błędne. W tym wypadku koniecznym jest wysokiej jakości układ diagnostyczny. Dlatego użyto głowicę laserową firmy Polytec. Na podstawie badań otrzymano wielowymiarową funkcję wibroakustyczną, w której dodatkową zmienną jest wartość momentu obrotowego. Zmierzone drgania zostały poddane operacją cyfrowego przetwarzania sygnałów, takich jak okienkowanie, FFT, filtracji z użyciem filtrów o skończonej odpowiedzi impulsowej, które zostały poddane dodatkowo operacją okienkowania. Rezultaty pomiarów i przetwarzania zostały zaprezentowane w postaci obrazowania 3D, które w wypadku tej metody diagnostycznej wydają się najlepsze. Ponadto autorzy prezentują rozwój układów EGR różnych generacji. Zasada pracy tego układu polega na wtłoczeniu do komory spalania części gazów wylotowych. Duża część użytkowników tego systemu twierdzi, że jego działanie ma negatywny wpływ na osiągi pojazdu. Nie można jednak stwierdzić czy twierdzenie to jest właściwe gdyż dotychczas brakuje badań prowadzonych w tym kierunku. Pomimo tego pewne jest, że zanieczyszczony zawór układu EGR na pewno będzie miał wpływ na osiągi pojazdu.
    Źródło:
    Diagnostyka; 2010, 4(56); 27-35
    1641-6414
    2449-5220
    Pojawia się w:
    Diagnostyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Challenges in assessing the vibrations influence on people in buildings using non-contact measurements
    Autorzy:
    Bróż, Natalia
    Nazarko, Piotr
    Powiązania:
    https://bibliotekanauki.pl/articles/16539555.pdf
    Data publikacji:
    2023
    Wydawca:
    Politechnika Rzeszowska im. Ignacego Łukasiewicza. Oficyna Wydawnicza
    Tematy:
    vibration measurements
    laser vibrometry
    vibration influence on people
    buildings
    signal processing
    pomiar drgań
    wibrometria laserowa
    wpływ drgań na ludzi
    budynek
    przetwarzanie sygnałów
    Opis:
    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.
    Źródło:
    Czasopismo Inżynierii Lądowej, Środowiska i Architektury; 2023, 70; 51--64
    2300-5130
    2300-8903
    Pojawia się w:
    Czasopismo Inżynierii Lądowej, Środowiska i Architektury
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-6 z 6

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