The Research Of Testing And Evaluating Methods Using Phased Array Ultrasonic

Comparing with conventional ultrasonic, Phased array ultrasonic has manyadvantages.However, there are no standards about the testing and evaluating methodsof PAUT in our country which influences a lot on the popularization and applicationof PAUT.In this project, theoretical analysis and experiments have been done for theinspecting technologies of the application using PAUT. With the help of the researchabove and application cases all over the world, the standard about the inspection usingPAUT of industrial inspection of our country can be defined.Refering to the standards and literature abroad,we design several blocks andmock-ups,make theoretical analysis and simulation calculation of PAUT usingCIVA,make assessment and analysis of technic parameters about the PAUTinstruments according to realistic workpiece inspecting,inspect with PAUT indifferent parameters and compare the result with the UT and RT.From the phased array ultrasonic system performance evaluating we can find thatwhen the number of the activatied elements increasing, the focal ability of the systemwill be better, the focal height will be larger and the focal spot will be smaller.Whenthe focal height increasing, the focal spot increases, too. The effect of wedge on focalability mainly depends on the steering angle and the sound path. When testing withwedge, most of the near field is in the wedge and the near field in the testpiece is verysmall.When the steering angles becomes smaller, the near field in the testpiecebecomes bigger. When the steering angle amplifies, the focal ability is weaker. Thereare few influences on beam profile of passive aperture when changing the number ofthe elements, the steering angles and the focal height.If the elements used in the testare less than or equal to16, the phased array ultrasonic beam steering limit would beweaker. When the picthes are the same, if there are more elements been used, thebetter ability of beam steering would be better. When the elements used are identical,if the pitch is bigger, the focal ability would be better.The simulation of phased array ultrasonic system performance evaluating is inconsistent with the truly experiment and the rules are the same. When the elementsused in the test are bigger than or equal to128, there would not been a valid focal range during200mm. Through the simulation of butt welds testing, we can find thatthrough PAUT, the number of the elements been used can not be suggested the morethe better.And the result will be better if we use more elements for thick testpieceinspecting.From the phased array ultrasonic butt welds testing experiment we can find that theentire POD of PAUT is better than UT except that the POD of slag with PAUTinspecting is slightly lower than the POD of UT.For point defect such as prosity,thelengths of the defect inspecting by PAUT is equal to the length inspecting by RT andbigger than the length inspecting by UT. For the lack of fusion, the length inspectingby PAUT and UT are bigger than the results of RT. For incomplete penetration, theresults of the three ways are nearly the same. For the longitudinal crack, the lenthinspecting by PAUT are the biggest and the results from RT are the smallest.The research of this paper directly instructs the codes about the performance of theinstruments and the inspecting techniques of the standard about PAUT. It hasextremely reliability, repeatability and pracaticality.