Determining the probability of detecting flaws in weld joints by phased-array ultrasonic testing

The article is devoted to ultrasonic testing of weld joints in aerospace industry with an acoustic phased array. Testing planar flaws of lack-of-fusion and joint-root-crack types by sector scanning is considered. A technique is suggested for calculating the probability of detecting flaws (POD) by means of numerical modeling of the ultrasonic-testing procedure with allowance for interferences. A finite-element model has been developed, and 40 cracks with randomly generated geometry have been modeled. Using the modeling results, a conditional crack height at a level of 10% of the echosignal amplitude from a reference reflector has been determined. POD curves have been calculated using the results of numerical experiments.