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.

Time of Flight Diffraction and Imaging (tofdi) Combining B-Scans and Cross-Sectional Imaging

Abstract: Time of Flight Diffraction and Imaging (ToFDI), based on Time of Flight Diffraction (ToFD), uses a sparse transducer array (laser‐EMAT for non‐contact applications), and adds an imaging stage based on multiple wave mode (and mode‐converted) ultrasound scattering by defects. B‐scans are processed to remove direct and reflected surface waves, enhance parabolas, and combine multiple B‐scans. Outputting an improved B‐scan and a cross‐sectional image, the final objective is the automated detection, identification, positioning and sizing for all defects in a sample.

A Comparative Study of Pulse-echo Method and TOFD Method for the Defect in the Welding Joint of the STS304 Stainless Steel

Abstract: For the evaluation of a flaw in a welded stainless steel by the Time of Flight Diffraction(TOFD) Method, we have made the reference specimen for experimentation. As a result, we could analyze a specific character and the inner state of the structure in a welded stainless steel and we came to the conclusion as followed. (1) For analyze the structure state of a section in a welded stainless steel through the optical microscope, we could have analyzed the generated shape and the location of a flaw and the inner parts of the structure state through the microscope of eighty magnification and two hundred magnification about the soundness, the heat affected zone(HAZ) and the welded part. (2) Through the comparison with the shape and the size of a flaw in the welded part about the conventional ultrasonic test and the TOFD Method, we could make an observation the special character of the TOFD Method and principles. (3) We analyzed and collected the merit of the TOFD Method on the basis of the experimental result by the shape and the size of a flaw in the inner welded parts. So, we made up a base that we could use as a basic data for a similar flaw like that. Through the study as mentioned above, we could make an observation the flaw detective method and principles used in the TOFD Method.

Development and application of contact-type line-focus ultrasonic probe

Abstract: A contact-type line-focus ultrasonic probe has been developed. The probe is composed of a quarter cylindrical wedge and a piezoelectric transducer attached to its cylindrical surface. A key feature of the developed probe is that longitudinal wave is incident to the testing object at all angles from 0° to 90° simultaneously. Basic characteristics of the probe have been examined by visualizing ultrasonic wave field and by evaluating the directivity. Some applications of the probe have been also investigated. It has been shown that the probe can transmit and receive Rayleigh and generalized Lamb waves in objects having relatively wide range of mechanical properties. It has been also shown that this probe can be applied to TOFD method.

Present development and prospect of special equipment testing in China

Abstract: The special equipment development status was analyzed by the view of special equipment definition,quantity,and managementThe features and development trends of pressure vessels,station boilers,hoisting machinery and electric elevator equipments were summarizedThe nondestructive testing techniques such as acoustic emission(AE) technique,magnetic flux leakage(MFL) detection,ultrasound phased array inspection,Time-of-flight diffraction(TOFD) and ultrasound guided wave techniques were summarized in this paperWe sugguested the development goal and task of special equipment testing in ChinaIt provides valuable references to safety quality inspection persons of special equipment

Ultrasonic Identification of Weld Defects Made by Butt Welding with Hot Plate on Plastic Pipelines

Abstract: This article describes usage of ultrasonic method TOFD for testing of welds on plastic pipelines welded with butt fusion with hot plate. As an artificial defects were selected cold fusion and inclusion in the weld area, by using metallic tape and wire as a mentioned defects. To test defects was necessary to use wedges with water as a bonding agent. Results of testing are proof of usefulness of this method. It can severely reduce risks of accidents caused by unidentified defects, which can occur in welded joints. Since plastic pipelines are used even in nuclear industry as a replacement for metal pipelines for its resistance against radiaton decay, it is necessary to implement similar testing regulations to avoid fatal incidents and method like TOFD and Phased Array ultrasonic testing can prevent such failures.