Ultrasonic testing (UT) is another widely applied inspection technology. Ultrasonic methods are an extremely diverse set of techniques based upon the generation and detection of mechanical vibrations or waves in test objects. The objects that can be tested are not limited to metals or even to solids.
The methods enabled by ultrasonic technology are often used to detect and size internal flaws in metals, ceramics and composites, but they can also be used to assess the integrity of interfacial material bonding, to measure thickness and extent of corrosion, and to determine physical properties such as the structure, grain size, and elastic constants of various materials.
The term ultrasonic refers to sound waves of frequency above the limit of human hearing, approximately 20 kHz. The frequencies between 1 and 10 MHz encompass the range used for most ultrasonic techniques, although lower and higher frequencies are sometimes used for special applications. Utrasonic velocity in a material is a simple function of its modulus and density, and thus ultrasonic methods are uniquely suited to materials characterization studies. In addition, the sound waves are strongly reflected at physical boundaries where materials properties change, and thus they are often used for thickness measurements and crack detection.
February 1, 2008
All Aircraft Survivability Journals published after 2014 were produced under the contract vehicle known as Survivability/Vulnerability Information Analysis Center (SURVIAC). The journal is now created by the Joint Aircraft Survivability Program (JASP).