Which type of wave does ultrasonic testing primarily utilize?

Ultrasonic testing primarily utilizes longitudinal waves due to their ability to propagate efficiently through various materials, allowing for effective detection of internal flaws, thickness measurements, and material characterization. In this testing method, sound waves are introduced into a material, and longitudinal waves travel along the direction of energy propagation. This type of wave compresses and decompresses the material, effectively transmitting energy and providing valuable information about the structure being tested.

Longitudinal waves are particularly useful in ultrasonic testing because they can penetrate deeper and provide information about internal conditions. Other wave types, such as transverse waves, are not as efficient in solid materials for this application and can be limited in their ability to travel, especially in metals, since they require a medium that can support shear stress. Surface waves and Rayleigh waves, while useful in some contexts like surface inspections, do not provide the same depth of insight into material integrity as longitudinal waves do in ultrasonic testing.