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    Wyświetlanie 1-5 z 5
    Tytuł:
    An overview of different possibilities to master the challenge of coupling an ae-sensor to an object of interest partly using examples of previous investigations
    Autorzy:
    Ziegler, Burkhard
    Dudzik, Krzysztof
    Powiązania:
    https://bibliotekanauki.pl/articles/242674.pdf
    Data publikacji:
    2019
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    acoustic emission sensor
    application
    mounting
    couplant
    waveguide
    Opis:
    Acoustic emission analysis is defined as a passive, non-destructive investigation method, which only listens for AEwaves (AEW), generated actively by an object of interest. Therefore, the AEW must have the possibility to propagate from their source to an acoustic emission sensor (AES). By virtue of the piezoelectric effect, the AEW transmitted into electrical signals inside of the AES. During the analysation of these electrical signals we earn –online– information about the object of interest, e.g. the operating characteristic of a machine or the strength of the friction of a tribolocical system. To enable the AEW to propagate into the AES, the sensor has to be fixed suitable onto the object of interest. Hereby has to be strictly respected, that the sensor is fixed in a reproducible mechanical way as well as to ensure that the through-transmission has a weak attenuation (couplant). Standard AES have the shape of a circular cylinder (diameter and height depend on the operation purpose), the AEW pass through one of the frontends into the sensor. The objects of interest can have different geometry of the surface (e.g. plane, cylindrical, unspecific) or temperatures which usually conflicting the operating range of the sensor. Depending on the operational purpose, there are many different couplants to use. This article offers help to master the different connecting challenges within the range of acoustic emission analysis.
    Źródło:
    Journal of KONES; 2019, 26, 1; 207-214
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Multi-Modal Acoustic Flow Decomposition Examined in a Hard Walled Cylindrical Duct
    Autorzy:
    Weyna, S.
    Mickiewicz, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/177391.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    acoustics flow
    sound intensity
    acoustic waveguide
    Opis:
    Flow fields could be of great interest in the study of sound propagation in aeroengines. For ducts with rigid boundaries, the fluid-resonant category may contribute significantly to unwanted noise. An understanding of the multi-modal propagation of acoustic waves in ducts is of practical interest for use in the control of noise in, for example, aero-engines, automotive exhaust and heating or ventilation systems. The purpose of our experiments was to test the acoustic energy transmission of duct modes based on studies carried out by the sound intensity technique. Sound intensity patterns in circular duct are discussed of modal energy analysis with particular reference to proper orthogonal decomposition and dynamic mode decomposition. The authors try to justify some advantages of the sound intensity experimental research in this area. In the paper, the wide-band sound signal propagated from source approximated with loudspeaker in hard-walled duct is imaged using a sound intensity – based approach. For a simple duct geometry, the sound intensity field is examined visually and by performing a modal decomposition greater insight into the acoustic structures is obtained. The image of sound intensity fields below and above “cut-off” frequency region are found to compare acoustic modes which might resonate in duct.
    Źródło:
    Archives of Acoustics; 2014, 39, 2; 289-296
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Calculation and optimization of waveguide geometry for acoustic emission signals
    Autorzy:
    Skalsky, V.
    Serhiyenko, O.
    Selivonchyk, T.
    Tolopko, Y.
    Powiązania:
    https://bibliotekanauki.pl/articles/329154.pdf
    Data publikacji:
    2009
    Wydawca:
    Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
    Tematy:
    emisja akustyczna
    metoda elementów skończonych
    strata energii
    temperatura
    falowód
    acoustic emission
    finite elements method
    waveguide
    energy losses
    temperature distribution
    Opis:
    Optimization of geometrical sizes of the waveguide of elastic acoustic emission (AE) waves, which is used in the search of hydrogen induced cracking during thermal cycling of structure alloys in a gaseous hydrogen environment, is considered. A waveguide is considered as on acoustic system that has the discrete spectrum of eigenfrequencies. Distribution of temperature field along the waveguide is calculated, decay of elastic AE waves is estimated. Basing on the obtained results the design implementation of the waveguide is carried out.
    Źródło:
    Diagnostyka; 2009, 1(49); 3-6
    1641-6414
    2449-5220
    Pojawia się w:
    Diagnostyka
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Transmission of Ultrasonic Waves Via Optical Silica Glass Fiber Doped by 7.5% of TiO2 with the Use of Power Sandwich Transducer
    Autorzy:
    Muc, S.
    Gudra, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/177364.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    ultrasounds
    transmission of acoustic wave in an optical waveguide
    Opis:
    The possibility of acoustic wave propagation in optical waveguides creates new prospects for simultaneous transmission of laser beams and ultrasonic waves. Combined laser-ultrasonic technology could be useful in e.g. surgical treatment. The article presents the results of experimental studies of transmission of ultrasonic wave in optical fibres, the core of which is doped by 7.5% of TiO2, using a sandwichtype transducer. It also presents amplitude characteristics of an ultrasonic signal propagated in the optical fibre. Authors studied the effect which the length of the fibre has on the achieved output signal amplitudes. They presented the relation of the output signal amplitude from a capacitive sensor to the power applied to the sandwich-type transducer. The obtained results were compared with the results produced when using an optical fibre with a core doped by 3% of GeO2, in order to select optical fibre suitable for simultaneous transmission of ultrasonic waves and laser rays.
    Źródło:
    Archives of Acoustics; 2011, 36, 1; 141-150
    0137-5075
    Pojawia się w:
    Archives of Acoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Diffraction of sound pulses on a spherical target in an oceanic waveguide covered with ice
    Autorzy:
    Grigorieva, N.
    Kupriyanov, M.
    Ostrovskiy, D.
    Stepanova, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/332177.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Akustyczne
    Tematy:
    diffraction of acoustic waves
    ice-covered homogeneous waveguide
    normal modes of the waveguide
    pulse with a Gaussian envelope
    surface waves
    Franz type
    Whispering Gallery type
    Opis:
    This paper is devoted to modeling of the pulse scattering by a spherical target immersed in a homogeneous waveguide covered with ice. For calculating the echo signal in the frequency domain we have followed Hackman and Sammelmann’s general approach. The arising scattering coefficients of a sphere were evaluated with the use of the normal mode method. The amount of normal modes forming the backscattered field is determined by the given directivity of the source. The emitted signal is a pulse with a Gaussian envelope. Computational results are obtained in a wide frequency range 8 - 12 kHz for water depths equal to several hundreds of m, and distances between the source/receiver and a target from 1 km up to 10 km. The target is assumed to be acoustically rigid or fluid. In particular, the properties of the ice cover and a scatterer may coincide.
    Źródło:
    Hydroacoustics; 2016, 19; 139-144
    1642-1817
    Pojawia się w:
    Hydroacoustics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-5 z 5

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