time-of-flight diffraction (TOFD)

An advanced ultrasonic testingA non-destructive testing (NDT) method that uses high-frequency sound waves to detect and evaluate internal flaws, discontinuities, or material properties in va… technique used for non-destructive evaluationThe use of various inspection and assessment techniques to evaluate the condition, integrity, and performance of pipelines without causing damage or requiring t… and flawAn imperfection smaller than the maximum allowable size. detection in materials and structures. It is particularly effective for detecting and sizing cracks, discontinuities, and other defects in welded joints.

TOFD is based on the measurement of diffracted ultrasoundRefers to sound waves with frequencies above the upper limit of human hearing, typically above 20,000 Hz. Ultrasound is used to determine wall thickness and to … waves that are produced when a sound wave encounters a crackA fracture or discontinuity in the wall of a pipeline, where the material is separated or broken, potentially compromising the integrity and safety of the pipel… or a defectA flaw, anomaly, or imperfection in a pipeline that could compromise its integrity, safety, or performance. Defects can vary in nature, size, and severity and c… in a material. The diffracted waves provide valuable information about the size, shape, and location of the defect. The diffracted signals are then received by sensors or transducers and analyzed.

TOFD typically involves the use of two ultrasonic probes positioned on opposite sides of the area being inspected. One probe emits an ultrasonic pulse, which propagates through the material, while the other probe receives the diffracted waves.