Method and apparatus for improving the transmitting and receiving directivity in long-range ultrasonic testing

An apparatus, comprising:

• a phased array probe comprising two channel transducers arranged on an object to be tested at an interval corresponding to a quarter wavelength of a center frequency of a guided wave pulse for long-range ultrasonic testing;
• and
• a signal processing unit configured to delay a phase of one of guided wave echo signals detected by each of the two channel transducers, adjust amplitudes of the phase-delayed guided wave echo signal and a non-phase delayed guided wave echo signal among the detected guided wave echo signals by using a phase difference between the phase-delayed guided wave echo signal and the non-phase delayed guided wave echo signal, and then sum up the two amplitude-adjusted guided wave echo signals.

A method performed using a phased array probe comprising two channel transducers arranged on an object to be tested at an interval corresponding to a quarter wavelength of a center frequency of a guided wave pulse for long-range ultrasonic testing, the method comprising:

• driving one transducer of the two channel transducers, which is disposed rearward with respect to an intended direction of the guided wave pulse, to transmit a forward guided wave pulse and a backward guided wave pulse into the object to be tested by supplying a first electric pulse to the channel transducer disposed rearward;
• and
• driving the other transducer of the two channel transducer, which is disposed forward with respect to the intended direction, to transmit a forward guided wave pulse and a backward guided wave pulse into the object to be tested by supplying a second electric pulse of a phase opposite to that of the first electric pulse to the channel transducer disposed forward after an elapse of a time interval corresponding to a quarter wavelength at the center frequency from a time of supplying the first electric pulse, thereby causing the two backward guided wave pulses transmitted by the channel transducer disposed forward and the channel transducer disposed rearward to overlap with each other without a time difference and form destructive interference.