Research On Simulation Technology Of Ultrasonic Inspection Based On The Multi-Gassian Beams

In recent years, with the development of ultrasonic inspection and the widespread application of computer technology, the simulation technology of ultrasonic inspection is becoming research focus.Based on the ultrasonic inspection system model, we can simulate the transducer ultrasonic radiation field and explore the accurate method of flaw identified and located, it is of great guiding significance in the actual process of ultrasonic inspection.This paper analyzed the ultrasonic propagation behavior, described the multi-Gaussian beam theory for the transducer beam. Because the model can be used to describe the transducer ultrasonic radiation field using simple analytical expression, it has high computational efficiency.On this basis,based on the multi-gaussian beams, The ultrasonic radiation field of circular piston transducer,rectangular piston transducer and elliptical piston transducer were simulated by MATLAB. Sound field of circular piston transducer of different sizes and different emission frequencies were also simulated. Because it is conducive to analyzing and comprehending sound field by an image directly and can avoid the complex analytic calculating process, it helps people understand the sound field intuitively.In order to verify the accuracy of the model,we compared the multi-Gaussion beams with the Rayleigh-Sommerfeld. It is found that MGB is accurate in the far-field and most near-field region.Thus it is reasonable and valid to analyze the actual ultrasonic inspection field using multi-Gaussion beamsOn the basis of multi-Gaussian beam theory and Kirchhoff's approximation theory, the measurement model of flat bottom hole was given, after the verification of the validity of the model, it was applied to evaluating the equivalence of defect. Towards ultrasonic contact testing, a practical AVG curve was charted using the measurement model of flat-bottom hole.Through comparing the new methld to the traditional methods, we can easily see that the new methold is accuracy and practicality, towards ultrasonic immersion testing,the reflection curve of workpiece front suface and the difference curve were given, and the paper also told that how to evaluate the equivalence of defect for ultrasonic immersion testing using the two curves.