Abstract
The ultrasonic testing has been applied to the quality control of welded joints of steel bridges. By the ultrasonic testing, one probe technique has been applied conventionally. Sometimes, however, detection of planar defects such as crack, incomplete penetration was di.cult by the one probe technique. Recently, phased array transducers have been developed. A phased array transducer consists of many small elements that can focus and change the refraction angles by controlling the excitation time of the elements. This study aims at the accurate non-destructive evaluation by the use of two phased array transducers. The testing system could reconstruct the image of side holes in a specimen of complicated shape very clearly. The testing system could detect an incomplete penetration and gave very accurate result of size estimation.
