Time-of-flight diffraction ultrasonics

About: Time-of-flight diffraction ultrasonics is a research topic. Over the lifetime, 544 publications have been published within this topic receiving 3189 citations.

A method of locating and sizing fatigue cracks

Abstract: A method of detecting and determining the size of fatigue cracks in steel components comprising: analyzing the component using a Time of Flight Diffraction (TOFD) ultrasonic technique to locate the crack tip; analyzing the component using a Phased Array Sectorial (PAS) ultrasonic technique to locate the crack corner trap; and calculating the distance between the crack tip and the crack corner trap to determine the size of the crack.

Time-of-Flight Diffraction Measurement Using Laser Ultrasound

Abstract: We developed a new time-of-flight diffraction (TOFD) method based on laser ultrasound, which can use not only longitudinal waves but also shear waves. This method is more advantageous than the conventional TOFD method, because it enables us to obtain flaw depths accurately without knowing the longitudinal or shear wave velocity in the specimen or the distance between the transmitter and receiver, which are not easily obtained in complex-shaped objects. We applied the proposed method to estimate slit depths in aluminum alloy plates. The times of flight of the lateral wave, diffracted waves and the mode-converted shear wave at the flaw tip were measured and used to estimate the slit depth. As a result, an accurate estimation of flaw depth was achieved.

An Ultrasonic Time of Flight Diffraction Technique for Characterization of Surface-Breaking Inclined Cracks

Abstract: This paper presents the development of a testing technique for measuring the angle of inclination and depth of surface-breaking inclined cracks in simple geometry components using a manual ultrasonic time of flight diffraction system. The testing technique in this work can be useful in risk based test planning for simple geometry components such as pipelines and boiler headers.

Simulation of ultrasonic testing technique by Finite Element Method

Abstract: Ultrasonic technique is a well-known technique for non-destructive detection of the material defect. In this paper, we develop the ultrasonic model of Finite Element Method (FEM) for the material crack detection in a two-dimensional geometry. The FEM Model is established by the geometry of the defect and the piezoelectric transducers with the finite element analysis software ANSYS. The reflected signals in ultrasonic techniques for the defect were simulated using the plane strain elements. The method with FEM for modeling the time-of-flight diffraction technique (TOFD) for the detection of the thick material (Thickness>15mm) is proposed, which is based on the diffraction phenomenon. The results from the simulation model are compared to the experimental signal to show the effectiveness of the FEM model.

Positioning method of transverse wave TOFD (Time of Flight Diffraction) defect

Abstract: In the ultrasonic nondestructive testing field, the traditional time of flight diffraction (TOFD) is used for finding defects of a welding line by only using a longitudinal wave scattering signal; because the type of used signals is single, the three-dimensional positioning of the internal defect of the welding line cannot be realized by the single linear scanning. Aiming the problem, the invention provides a transverse wave TOFD detecting method; one pair of transverse wave probes are used for performing the single linear scanning along the welding line; at the same time, the longitudinal wave and the transverse wave scattering signals of the internal defect of the welding line are used for analyzing to point out that the defect is located on an elliptic trajectory determined by the transverse wave scattering signal and is also located on a circular trajectory determined by the longitudinal wave scattering signal, thus the three-dimensional positioning of the internal defect of the material can be realized by obtaining the intersecting point of the two curves.