Ultrasonic Phased Array
The basic idea of ultrasonic phased array technology comes from radar electromagnetic wave phased array technology. Phased array radar is composed of many radiating elements arranged in an array. By controlling the amplitude and phase of each element in the array antenna, the radiation direction of electromagnetic waves can be adjusted to synthesize a flexible and fast focusing and scanning radar beam within a certain space. The ultrasonic phased array transducer is composed of multiple independent piezoelectric wafers. The electronic system controls and excites each wafer unit according to certain rules and timing to adjust and control the position of the focus and the direction of focus.
Ultrasonic phased array is a combination of ultrasonic probe wafers. A number of piezoelectric wafers are arranged in a certain regular distribution, and then each wafer is excited successively according to a predetermined delay time. The ultrasonic waves emitted by all wafers form an overall wavefront, which can be effective Ground control of the shape and direction of the transmitted ultrasonic beam (wavefront) can realize the scanning, deflection and focusing of the ultrasonic beam. It provides greater capabilities than single or multiple probe systems for determining the shape, size, and direction of discontinuities.
Ultrasonic phased array detection technology uses multi-element transducers of different shapes to generate and receive ultrasonic beams. By controlling the different delay time of each element in the transducer array to transmit (or receive) pulses, the arrival (or from) of the sound waves can be changed. The phase relationship at a certain point in the object realizes the change of the focus and the direction of the sound beam, so as to realize the scanning, deflection and focusing of the ultrasonic beam. Then use a combination of mechanical scanning and electronic scanning to achieve image imaging.
The one-dimensional linear array probe is usually used, the piezoelectric wafers are arranged in a straight line, and the focused sound field is sheet-shaped, which can obtain two-dimensional images of defects, and is widely used in industry.
When using a phased array probe to detect welds, there is no need to frequently move back and forth, left and right, on both sides of the weld like a normal single probe, while the phased array probe performs linear scanning along the length of the weld parallel to the weld. Full volume inspection of welded joints. This scanning method can be completed by sliding along a precisely positioned track with the aid of a mechanical scanner equipped with an array probe, or it can be completed manually, which can realize rapid detection and has a very high detection efficiency.
