Guide wave transmission and reception method

Abstract

This generates a tuned waveform for any propagation mode determined by the material constants and input frequency in a guided wave. [Solution] By performing a theoretical analysis based on the wave equation satisfied by the guided wave, the conditions under which a specific propagation mode is strongly excited are identified. Data processing is then performed to satisfy the spatiotemporal resonance conditions (tuning conditions) based on the theoretical analysis, enabling the transmission and reception of a specific propagation mode.

Claims

1. The transducer is scanned in the direction of ultrasonic propagation, and the ultrasonic data obtained from the scan is used to perform data processing that satisfies spatiotemporal resonance conditions (tuning conditions). This generates a tuned waveform for any propagation mode in the propagation modes, which are the states of ultrasonic propagation, and transmits and receives a specific propagation mode. A method for transmitting and receiving guided waves, characterized by the following:

2. In the method for transmitting and receiving guided waves according to claim 1, To simulate scanning the entire excitation range of an ultrasonic wave, a composite waveform (virtual excitation wave packet) is generated by phase-adjusting so that it is excited at the wavelength of the selected propagation mode. A group of virtual excitation wave packets is then generated, and various tuning conditions are applied to this group of virtual excitation wave packets. A method for transmitting and receiving guided waves, characterized by the following:

3. In the method for transmitting and receiving guided waves according to claim 1, The probe is scanned in a direction intersecting the propagation direction, and a waveform that satisfies the resonance conditions (tuning conditions) is created, including the transmission and reception position information in the intersecting direction. A method for transmitting and receiving guided waves, characterized by the following:

4. A method for transmitting and receiving guided waves according to any one of claims 1 to 3, The aforementioned propagation mode has a group velocity and a phase velocity that depend on the input frequency. The group velocity corresponds to the propagation velocity of any propagation mode, The phase velocity can be determined from the wavenumber corresponding to the frequency of any propagation mode. A method for transmitting and receiving guided waves, characterized by the following:

5. In the method for transmitting and receiving guided waves according to claim 4, The resonance conditions (tuning conditions) in the data processing for generating the tuned waveform of the propagation mode are: The group velocity tuning conditions for the group velocity and the phase tuning conditions for the wavenumber are as follows: During transmission and reception, the ultrasonic waveforms are superimposed to satisfy the tuning conditions corresponding to the transmission and reception position of the transducer. A method for transmitting and receiving guided waves, characterized by the following:

6. In the method for transmitting and receiving guided waves according to claim 5, The group velocity synchronization conditions for the aforementioned group velocity are: The transmission time of the ultrasonic waves from the transducer during scanning is adjusted according to the position of the transducer before and after scanning, and the group velocity (propagation speed), so that the transducer is sequentially excited at each position in accordance with the propagation speed of the guide wave. The phase tuning conditions for the aforementioned phase velocity are: Depending on the position, wavenumber, angular frequency, and imaginary unit of the probe before and after scanning, This is a condition for adjusting the phase of the ultrasonic waves of the probe during scanning to generate spatial resonance. A method for transmitting and receiving guided waves, characterized by the following:

7. A method for transmitting and receiving guided waves according to any one of claims 1 to 3, The aforementioned specific propagation mode is used as a signal for evaluating the waveguide under inspection. A method for transmitting and receiving guided waves, characterized by the following:

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