NDT Acoustic Emission Testing 2

Question 1

What is the primary function of a preamplifier in an acoustic emission testing system?

Accepted Answer

To amplify the small AE sensor signal before transmission to the main amplifier

Answer

To filter out high-frequency noise above 1 MHz

Answer

To digitize the AE waveform at the point of detection

Answer

To provide electrical isolation between the sensor and the data acquisition unit

Question 2

The Hit Definition Time (HDT) parameter in AE data acquisition is used to:

Accepted Answer

Determine when an AE hit has ended by timing from the last threshold crossing

Answer

Set the maximum allowable signal duration before the system resets

Answer

Define the time window used for source location calculations

Answer

Control the delay between successive pencil lead break calibrations

Question 3

For linear source location in acoustic emission testing, what is the minimum number of sensors required?

Accepted Answer

Two

Answer

One

Answer

Three

Answer

Four

Question 4

Which of the following best describes signal attenuation in acoustic emission testing?

Accepted Answer

The loss of AE signal amplitude as the wave propagates through the material

Answer

The increase in AE signal frequency as it travels away from the source

Answer

The reflection of AE waves at the back wall of the test specimen

Answer

The conversion of longitudinal AE waves into shear waves at boundaries

Question 5

The detection threshold in an AE system is set to:

Accepted Answer

Exclude background electromagnetic noise while capturing true AE signals

Answer

Match the resonant frequency of the piezoelectric sensor

Answer

Limit the maximum amplitude of signals stored in the database

Answer

Define the upper boundary of the frequency bandpass filter

Question 6

A couplant is used between an AE sensor and the test surface primarily to:

Accepted Answer

Ensure efficient transfer of acoustic waves from the surface into the sensor

Answer

Reduce the electrical resistance between the sensor and the component

Answer

Protect the sensor from high-temperature environments during testing

Answer

Increase the resonant frequency response of the piezoelectric element

Question 7

In acoustic emission testing, the term 'event' (as opposed to 'hit') refers to:

Accepted Answer

A single source occurrence detected by two or more sensors nearly simultaneously

Answer

Any signal that exceeds the preset amplitude threshold

Answer

A burst emission with duration greater than 1 millisecond

Answer

The electrical noise spike generated when the preamplifier saturates