摘要:

A sequenctial-type synthetic aperture ultrasonic flaw dection technique has been investigated, which shows high resolving power in the flaw detection in steel. The computer simulation for image reconstruction by this technique showed that the lateral resolution of one wavelength can be attained when the aperture angle is about 90 degree and one-cycle burst signal is used. Based on the simulation results an experimental system for applying this technique has been developed. In this system the diverging-beam transducer connected to an ultrasonic flaw detector is moved along the object surface, and the received signals can be formed into a sectional image within one minute by using a newly developed echo location component. As predicted in the simulation, the experiments on the steel block specimens verified the capability of the system to reconstruct the sectional images of flaws with the lateral resolution of about 1mm (at 5MHz) regardless of the distance to the tested region. By using this technique the accuracy of flaw evaluation can be improved in ultrasonic nondestructive testing

ISSN:0278-0895    

DOI:10.1080/0278-0898708952939

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A three-ellipsoid intersection method is formulated to locate a defect inside a piece of metal in three-dimensional space

ISSN:0278-0895    

DOI:10.1080/0278-0898708952940

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A forward Compton scatter gamma-ray imaging device is briefly described and the gamma-ray absorption in mild-steel samples containing voids is discussed. It is shown that in general any corrections for absorption invariably produces artifacts in the images of regions around voids, although this phenomenon is less significant for smaller voids and less dense materials

ISSN:0278-0895    

DOI:10.1080/0278-0898708952941

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The eddy-current touch method of crack detection can size cracks from the changes in the characteristics of the lift-off curves. Results obtained for mild steel samples show accuracies better than those obtained with the ACPD method for crack depths of 5 mm and less. For materials, such as different types of steels, having not very dissimilar properties, a calibration block for one type can be used for another. This is advantageous with the testing of welds

ISSN:0278-0895    

DOI:10.1080/0278-0898708952942

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0278-0895    

DOI:10.1080/0278-0898708952943

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor