Understanding Acoustic Emission Testing- Reading 1 Part B-A

Discussion
Subject: Wave Mode and Velocity
As mentioned earlier, using AE inspection in conjunction with other NDE techniques can be an effective method in gauging the location and nature of defects. Since source locations are
determined by the time required for the wave to travel through the material to a sensor, it is important that the velocity of the propagating waves be accurately calculated. This is not an easy task
since wave propagation depends on the material in question and the wave mode being detected. For many applications, Lamb waves
are of primary concern because they are able to give the best indication of
wave propagation from a source whose distance from the sensor is larger
than the thickness of the material.
Question: from the additional reading, “Lamb waves, also known as plate
waves, are another type of ultrasonic wave used in the nondestructive
inspection of materials. Lamb waves are propagated in plates (made of
composites or metals) only a few wavelengths thick”. Discuss on this
statement.
Charlie Chong/ Fion Zhang