Accurately sizing cracks has been a main objective of ultrasonic nondestructive evaluation for decades. Early sizing techniques based on echo amplitude have repeatedly been shown to be deficient. Diffraction techniques offer a significant improvement, but are also limited by pulse length and reliance on operator interpretation. In particular, Time-Of-Flight Diffraction is limited by pulse lengt...

A line-focus ultrasonic SH-wave probe is developed for possible application to TOFD method. The probe is composed of a quarteror half-cylindrical wedge and a piezoelectric transducer adhered to the cylindrical surface of the wedge. An SH-wave pulse with cylindrical wave front is generated by the transducer, transmitted to the wedge, and focused on a line at the bottom surface of the wedge. Henc...

when testing the defect by ultrasonic time of flight diffraction (TOFD), the image signal detected is often reshaped and resulted in inaccuracy of defect measurements because the probe beam has a limited range. This paper proposed an image enhancement method based on synthetic aperture focusing technique (SAFT). A mathematical model of testing image was first established based on the generation...

The European regulation regarding pressure equipment (i.e. Pressure Equipment Directive PED 97/23/CE) is applicable since May 2002. The member states have since adopted regulations enabling the use of innovative NDE methods such as acoustic emission as a global method associated to a local method such as TOFD technique which permits an accurate characterization and precise sizing of flaw indica...