The non-destructive testing method of ultrasounds, an excellent tool for solving fracture mechanics problems

The objective of this review paper is the presentation of the ability and the necessity of the non-destructive testing (NDT) method of ultrasounds for studying fracture mechanics (FM) problems. The discipline of FM provides the quantitative relationship, between stress, flaw size and toughness. Ultrasounds are mechanical elastic waves of very high frequency, which can be used for the material testing. Using ultrasounds, defects, discontinuities and dimensions of materials and structures can be easily evaluated. Many of a materials' mechanical properties such as the moduli of elasticity, the hardness, the damage and with a satisfactory approach, in many cases, the fracture strength, can also be determined. In the present paper some advanced applications of the ultrasonic method for the materials' characterisation take place. All these results arise, simply, using only the velocities and the attenuation coefficient of ultrasonic waves.