Research On Ultrasonic Debond Testing Based On Phased Array Technology

Ultrasonic phased array testing technology is a new trend in the field of Non-destructivetesting industry. It can produce flexible, controllable synthesized sound beams to realizefocusing and high-speed scanning by exciting each element of the array with independentphased delay. In recent years, the technology of ultrasonic phased array is becoming highlyrecognized both in domestic and foreign NDT research domain. In this article, the basicprinciple of phased array testing technology is studied theoretically and experimentally.The article can be divided into three major sections. The first one is the research onultrasonic phased array field which can provide theoretical basis for the following numericalcomputation of simulation experiment and array transducer design. The sound field model ofdifferent single transducers and array transducers is established for further simulation study oftheir space radiation both in single and multiplayer transmission medium. Meanwhile,systemic research on space directivity of single and array transducer provide the principle inthe process of designing transducer. Then the selecting law of parameter of array transducer isobtained through analyzing the influence of each parameter on sound field. Emission andreception with high precision of the beam is the key factor in the process of testing. As aresult, the second section mainly studied the testing principle and established the space-timecontrol model to master the methods of controlling sound beams and time-delay calculating.Take a test piece with a hole defect inside for a example, phased array ultrasonic testingdevice made by R/D Tech Company is used to detect such defect. The obtained data isanalyzed based on the mastery of data processing law of the device. Meanwhile, thesimulation experiment of defect detection is presented. The simulation results, compared withpractical experiments results, verify the truth of the theory of phased array ultrasonic testingand simulation results. According to it, the feasibility of ultrasonic phased array debondingtesting in the mood of simulation is studied for further research on rocket motor heatinsulation ultrasonic phased array debond testing. In the third part, phase deviation of the echocaused by perturbation of system and materials in practical experimental process is introduced.The reason of phase deviation and its influence on system is analyzed. After that, phasedeviation model is established. Then cross-covariance and time-reversal analysis methods aresuggested to correct the deviation according to the model. Both simulating and practicalexperiment results have proven that the two methods above have good correction capacity.Systematic signal-to-noise ratio and defect detection resolution is upgraded.Above all, the research findings above has great significance and use value for ournon-destructive testing development.