Final answer:
The two main ultrasonic waveforms used in ultrasonic testing are transverse waves (shear waves) and longitudinal waves (compression waves).
Step-by-step explanation:
The two main ultrasonic waveforms used in ultrasonic testing are transverse waves and longitudinal waves. Transverse waves are also known as shear waves, and in these waves, the disturbance travels perpendicular to the direction of wave propagation. Longitudinal waves, sometimes called compression waves or compressional waves, have disturbances that move parallel to the direction of wave propagation. For example, sound waves in air and water are longitudinal due to the periodic variations in pressure, while in solids, sound can propagate as both transverse and longitudinal waves.