Applications of multimode regime of total focusing method (TFM) for definition the type of reflector

Speaker:
Tikhonov, Dmitry; SPC ECHO+ Ltd; Russian Federation

Authors:
Bazulin, E.G.; Echoplus Ltd; Russia
Vopilkin, A.K.; Echoplus Ltd; Russia
Tikhonov, D.S.; Echoplus Ltd; Russia

ID: ECNDT-0618-2018

Definition of the reflector type and sizes is the most important problem of the operational ultrasonic control. Information about the reflector type, its sizes and coordinates will allow to make valid conclusion about danger level of such reflector for object operation. One of the solutions of this task is imaging of all border of the reflector. It is possible to use two phased arrayы located from the different sides of the reflector. For the phased array located to the left of the reflector (N-channel) it is possible to receive a set of partial images of the reflector accounting wave type transformation at the repeated reflections of the ultrasonic impulse (the multimode regime). A similar set of images could be received from the echo signals measured by the phased array located to the right of the reflector (P-channel) and from the echo signals measured at the radiation and reception by different phased arrays (NP-channel). Integration of partial images receiving from all channels by the large quantity of acoustic schemes allows to receive the image of all reflector border and to make a valid conclusion about reflector type. With smaller efficiency this approach allows to get information about reflector type when access is only one side. To improve the image quality, the measured echo signals can be subjected to the procedure of extrapolation its spectrums for reduction the impulses length. Several examples of the restored reflectors images in different controlled objects with two- and one-side access are given to demonstrate this method.