Re: Phased Arrays : Could anyone tell me how Phased-Array-Systems work or does anyone know where I can find information on that topic? . The basic premise for all PA systems involves an array transducer consisting of a set of small, individual elements that are independently driven. Although these elements may be pulsed individually, or in groups, to simulate conventional transducer excitation, the real strength of this technique lies in the capability of the system to electronically delay these elements during both generation and reception of ultrasonic signals. The wave-fronts produced by subsets of elements interact within the inspected component to produce a resultant, phase-integrated ultrasonic wave. The PA system can therefore steer and focus the integrated ultrasonic beam within the component.
I have been using phased-array UT (PAUT) for about three years now. We use a system built by R/D Tech to inspect a new type of weldment called "Friction Stir Welds" (FSW).
The PAUT has a 'water wedge', similar to immersion, and is very adapt at finding extremely tight lack-of-penetration, where other methods such as RT, PT, and even conventional UT, will have major troubles detecting the flaw.
NASA and Lockheed-Martin are implementing this PAUT inspection on the new FSW on the External Tank. Boeing has been using the PAUT on FSW as well, and recently launched a rocket with FSW inspected by the R/D Tech system.
09:13 Dec-16-2002 Paul A. Meyer R & D, GE Inspection Technologies, USA, Joined Nov 1998 47
Re: Phased Arrays :Hi Stefan, I am sure you understand that a sound field can be focused using a lens or a curved piezoelectric source. These techniques delay the sound from some areas of the aperture relative to other areas. In a phased-array system, the active transducer area is segmented into smaller areas, each of which can be controlled independently. By delaying certain areas, the resulting sound field can be made to simulate a focused or steered transducer. The advantage is that the steering and focusing are under electronic control and can be changed on a rep-rate basis.
I have some PowerPoint presentations that demonstrate the process. Contact me and I'll send you a copy.
Could anyone tell me how Phased-Array-Systems work or does anyone know where I can find information on that topic? .