NDT Ultrasonic Testing 3

Question 1

What is the significance of the 'acoustic impedance mismatch' at a material interface?

Accepted Answer

It controls the proportion of sound energy reflected versus transmitted at the interface

Answer

The greater the acoustic impedance mismatch between two materials, the higher the percentage of sound energy reflected at the interface rather than transmitted through it.

Question 2

In phased array ultrasonic testing (PAUT), what enables steering of the beam without physically moving the probe?

Accepted Answer

Electronic time delays applied to individual array elements

Answer

PAUT steers and focuses the beam by applying precisely calculated electronic time delays to fire individual array elements in a controlled sequence.

Question 3

Which type of wave travels along the surface of a material and is useful for detecting shallow surface-breaking flaws?

Accepted Answer

Surface (Rayleigh) wave

Answer

Rayleigh (surface) waves travel along the material surface with particle motion that is elliptical, making them sensitive to surface and near-surface discontinuities.

Question 4

What does 'DAC' stand for in ultrasonic testing, and what is its purpose?

Accepted Answer

Distance Amplitude Correction — compensates for signal loss with increasing sound path distance

Answer

Distance Amplitude Correction (DAC) is a reference curve that accounts for natural signal amplitude decrease with increasing depth, enabling consistent flaw evaluation at all depths.

Question 5

When calibrating an angle beam transducer using an IIW block, which feature is used to set the beam index point (BIP)?

Accepted Answer

The 50 mm radius curved surface

Answer

The 100 mm (or 50 mm) radius curved surface of the IIW block is used to locate the beam exit point (BIP) by maximizing the reflection from the curved surface.

NDT - Non-Destructive Testing Practice Test

NDT - Non-Destructive Testing Practice Test

NDT Ultrasonic Testing 3