REVIEW OF ULTRASONIC TESTING TECHNIQUE

Ultrasonic testing is based on time-varying deformations or vibrations in materials, commonly referred to as acoustics. The objective of this review is to elucidate the principles of ultrasonic testing, emphasizing the vibrational dynamics at the atomic level and their relevance in nondestructive evaluation (NDE). The methodology explored includes a detailed examination of sound wave propagation in solids, discussing four principal modes of sound waves—longitudinal, shear, surface, and plate waves. The longitudinal and shear waves, which are predominant in ultrasonic testing, are characterized by oscillations that occur either in the direction of wave propagation or perpendicular to it. Results indicate that when materials are not stressed beyond their elastic limit, the particles within them execute elastic oscillations influenced by internal restoration forces. By establishing a connection between elastic restoring forces and the inertia of particles, this review illustrates the fundamental mechanisms behind the oscillatory motions in the medium, which are critical to the efficiency and effectiveness of ultrasonic testing techniques.