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
What is the primary function of a preamplifier in an acoustic emission testing system?
Answer: To amplify the small AE sensor signal before transmission to the main amplifier
The preamplifier amplifies the low-voltage AE signal (typically microvolts to millivolts) close to the sensor to improve the signal-to-noise ratio before the signal travels through cables to the main system.
The Hit Definition Time (HDT) parameter in AE data acquisition is used to:
Answer: Determine when an AE hit has ended by timing from the last threshold crossing
HDT (also called hit lockout time) defines how long after the last threshold crossing the system waits before declaring a hit complete, preventing a single emission from being split into multiple hits.
For linear source location in acoustic emission testing, what is the minimum number of sensors required?
Answer: Two
Linear (1D) source location requires at least two sensors; the source position along a line is calculated from the difference in arrival times (delta-T) between the two sensors.
Which of the following best describes signal attenuation in acoustic emission testing?
Answer: The loss of AE signal amplitude as the wave propagates through the material
Attenuation in AE testing refers to the reduction of signal amplitude with increasing distance from the source due to geometric spreading, material damping, and scattering.
The detection threshold in an AE system is set to:
Answer: Exclude background electromagnetic noise while capturing true AE signals
The detection threshold is a voltage level set above the background noise floor so that only genuine AE signals exceeding it are recorded, preventing false hits from electrical or mechanical noise.
A couplant is used between an AE sensor and the test surface primarily to:
Answer: Ensure efficient transfer of acoustic waves from the surface into the sensor
Couplant fills air gaps between the sensor face and the test surface, which would otherwise severely impede the transmission of high-frequency stress waves into the sensor.
In acoustic emission testing, the term 'event' (as opposed to 'hit') refers to:
Answer: A single source occurrence detected by two or more sensors nearly simultaneously
An AE event is a single physical source occurrence (e.g., a micro-crack) that may generate hits on multiple sensors; grouping hits from the same source into one event allows for source location.