Practice Test GeeksNDT - Non-Destructive Testing Practice Test
← All NDT Flashcard Decks

Acoustic Emission Testing Flashcards

7 cards from real NDT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Acoustic Emission Testing flashcards as text

  1. What is the fundamental principle behind acoustic emission (AE) testing?

    Answer: Materials release transient elastic waves when undergoing deformation or damage

    AE testing detects transient elastic stress waves that are spontaneously emitted when a material undergoes deformation, cracking, or other damage mechanisms.

  2. The Kaiser Effect in acoustic emission testing refers to:

    Answer: The absence of detectable AE until a previously applied stress level is exceeded

    The Kaiser Effect states that a material will not emit acoustic emissions during reloading until the previous maximum stress level has been exceeded, indicating no irreversible damage during the prior load.

  3. Which AE signal parameter represents the highest voltage peak of the AE waveform above the threshold?

    Answer: Amplitude

    Amplitude is the peak voltage of the AE signal waveform above the detection threshold and is typically expressed in decibels (dBAE).

  4. The Felicity Ratio is defined as the ratio of:

    Answer: The load at which AE reappears during reloading to the previous maximum load

    The Felicity Ratio = (load at which AE reappears) / (previous maximum load); a ratio less than 1.0 indicates the Felicity Effect and suggests significant damage in the structure.

  5. What is the primary purpose of a pencil lead break (PLB) test in acoustic emission testing?

    Answer: To simulate an AE source and verify sensor coupling and system sensitivity

    A PLB test (Hsu-Nielsen source) simulates an AE event to verify that sensors are properly coupled to the structure and that the entire AE system is functioning with adequate sensitivity.

  6. Which type of sensor is most commonly used in acoustic emission testing?

    Answer: Piezoelectric transducer

    Piezoelectric transducers are the standard AE sensors because they efficiently convert surface motion (displacement/velocity) into electrical signals over the frequency ranges used in AE testing.

  7. In acoustic emission testing, 'counts' refers to:

    Answer: The number of times the AE signal crosses the detection threshold

    AE counts (or ring-down counts) are the number of times the rectified signal envelope exceeds the detection threshold within a single hit, providing a rough measure of signal intensity.