Detection of longitudinal and shear acoustic waves in solids

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SUMMARY

The discussion focuses on differentiating between longitudinal (P) and shear (S) acoustic waves in solids using an Acoustic Emission (AE) sensor positioned 2 to 20 cm from an AE source, such as a stress-induced crack. It is established that P waves travel at approximately twice the velocity of S waves, and S waves exhibit lower frequencies. The participant hypothesizes that frequency analysis, possibly through time-frequency graphs or wavelet analysis, can effectively distinguish between the two wave types. The inquiry emphasizes the need for information on the frequency characteristics of these waves, particularly in the context of stress-induced cracks in materials like metal.

PREREQUISITES
  • Understanding of Acoustic Emission (AE) technology
  • Knowledge of wave propagation in solids
  • Familiarity with frequency analysis techniques
  • Experience with time-frequency analysis and wavelet transforms
NEXT STEPS
  • Research the frequency characteristics of P and S waves in various materials
  • Learn about wavelet analysis for signal processing in acoustic emissions
  • Explore time-frequency analysis methods for distinguishing wave types
  • Investigate case studies on stress-induced cracks and their acoustic signatures
USEFUL FOR

Researchers, engineers, and professionals in materials science and acoustic engineering who are focused on analyzing acoustic emissions and understanding wave propagation in solids.

johnotoole3
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I want to be able to differentiate between longitudinal(P) and Shear(S) waves in solids. Using one Acoustic emission (AE) senor placed 2 to 20 cm form a AE source e.g. a stress induced crack or pencil lead test, how can one detect both the P and S waves and determine what part of the receive waveform corresponds to which wave. I know that the P wave travels typically at twice the velocity of the S wave and also that the S wave has lower frequency (at least this is true in seismology). My hypothesis is to use analysis of the frequency and maybe with a time-frequency graph I may be able to detect when each wave mode occurs. Maybe a filter or wavelet analysis could also be helpful.
My question is basically: Do the two waves occur at different frequencies and if so what sort of difference? Is it pratical to use some sort of frequency based technique to determine when each wave has arrived at a particular sensor? Does a crack from stress being applied to a material e.g metal produce a destinct P and S wave at different frequencies or are they blended into each other somehow?
 
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Does no one out there have any infor for the above problem or even where would i find it. I have been reading books and papers and all i can find is that the velocity difference between the two wave modes nothing on frequency. A source of information on acoustic waveforms would be greatly appreciated!
 

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