Experiment name: Application of power amplifier in testing of new omnidirectional high-order SH guided wave piezoelectric transducer.
Research direction: Ultrasonic guided waves
Experiment content:
The excitation function of the thickness shear type (d15) omnidirectional piezoelectric transducer was derived, and based on this, a single circular ring transducer was designed that can be used to selectively excite and receive high-order SH guided waves. Under different excitation voltage signals, the omnidirectionality, mode selectivity, wide/narrow/frequency shifting operating characteristics of the transducer were tested.
Test purpose: to verify the correctness of the theoretical derivation and ensure that the high-order SH guided wave mode can be selectively excited.
Test Equipment:
Function generator, SLA-HV-200S power amplifier, oscilloscope, laser vibrometer, shear type (d15) piezoelectric ring, aluminum plate, etc. Experimental process: The pulse electrical signal modulated by the Hanning window is generated by a function generator. After being amplified by a power amplifier (SLA-HV-200S, Saluki), it drives the shear type (d15) piezoelectric ring pasted on the aluminum plate for energy conversion. The device (OSH-PT) generates circumferential shear deformation, thereby stimulating omnidirectionally propagating SH guided waves in the aluminum plate. Based on the theoretically derived excitation formula, an OSH-PT with mode selection function can be designed. The in-plane displacement field spectrum obtained by excitation is measured by a Doppler laser vibrometer and collected by an oscilloscope. The electrical signal triggering, laser scanning, acquisition and other processes in the experiment are automatically completed through the Labview program on the laptop computer.
Test Results:
The theoretical results are in good agreement with the experimental results. The designed omnidirectional high-order SH guided wave transducer can excite the target SH guided wave mode while well suppressing the generation of other SH guided wave modes, which is helpful to promote the application of high-order SH guided waves in structural tomography.
