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Metode za merjenje hitrosti vibracij površin brez kontakta so trenutno zelo drage. Iz osnov tehnične akustike je teoretično možno meriti vibracije z zvočnim tlakom. Torej nas zanima, ali lahko vibracije merimo z mikrofonom, kar je bistveno cenejša izbira kot na primer merjenje z laserskim vibrometrom. Merili smo zvočni tlak z mikrofonom ter hitrost vibracij z laserskim vibrometrom. Zanima nas povezava med tema dvema veličinama in vplivi frekvence ter jakosti vira. Iz meritev smo nato ugotovili, da sta zvočni tlak in hitrost vibracij linearno odvisna. Linearni koeficient, ki povezuje zvočni tlak in hitrost vibracij, narašča linearno z višanjem frekvence. Jakost vira ne vpliva na koeficient. Pri meritvah moramo biti pozorni na velikost izbranega vira in njegove lastnosti. Zvočni tlak je indikator vibracij in je primeren za merjenje hitrosti in analizo vibracij površin. Methods for measuring velocity of vibration of surfaces without contact are currently very expensive. From the basics of technical acoustics it is theoretically possible to measure vibrations with sound pressure. So, we wonder whether vibrations can be measured with a microphone, which is a much cheaper choice than, for example, a laser vibrometer. We measured acoustic pressure with a microphone and velocity of vibrations with a laser vibrometer. We are interested in the connection between these two and the effects of the frequency and the power of the source. From the measurements we then found that sound pressure and velocity of vibrations are linearly dependent. The linear coefficient connecting soud pressure and velocity of vibrations increases linearly by increasing the frequency. Power of the source does not affect the coefficient. We have also learned that when measuring, we need to be aware of the size of chosen vibrating source and its properties. Sound pressure is an indicator of vibrations and is suitable for measuring the velocity and analisys of surface vibrations. |
