Sound beam focusing using phased array- SAFT technique

摘要

An integrated approach to sound beam focusing using phased arrays and the synthetic aperture focusing technique, called phased array SAFT (PA-SAFT), has been developed. The technique is based on acquiring the raw B-scan image using a divergent sound beam emanating from an active aperture of a linear array and then carrying out SAFT processing of the raw data to achieve sound beam focusing throughout the thickness of the sample. The size of the active aperture for data acquisition is optimised by simulation and experimental studies. The sensitivity and the lateral resolution for flaw detection by the PA-SAFTtechnique are assessed on aluminium and carbon steel samples. The results obtained by this technique are compared with those obtained by the full matrix capture total focusing method. The focusing ability of the PA-SAFT technique is utilised for accurate through-wall sizing of a 'natural' lack ofsidewall fusion in a weld joint.