Application Cases

Experiment Name: Application of Power Amplifier in Testing of Novel Omnidirectional High-Order SH Guided Wave Piezoelectric Transducers

Research Direction: Ultrasonic Guided Waves

Test Objective: To verify the correctness of the theoretical derivation and ensure that high-order SH guided wave modes can be selectively excited.

Experimental Content: The excitation function of a thickness-shear (d15) omnidirectional piezoelectric transducer was derived. Based on this, a single-ring transducer capable of selectively exciting and receiving high-order SH guided waves was designed. Under different excitation voltage signals, the transducer's omnidirectionality, mode selectivity, and broadband/narrowband/frequency-shifting operational characteristics were tested.

Testing Equipment: Function generator, ATA-2021 high-voltage amplifier, oscilloscope, laser Doppler vibrometer, shear-type (d15) piezoelectric ring, aluminum plate, etc.

Experimental Procedure: A Hanning-window modulated pulse electrical signal was generated by a function generator and amplified by a power amplifier (ATA-2021H). The amplified signal was then used to drive a shear-type (d15) piezoelectric ring transducer (OSH-PT) bonded to an aluminum plate, inducing circumferential shear deformation and thereby exciting omnidirectionally propagating SH guided waves in the plate. Based on the theoretically derived excitation formula, the OSH-PT was designed with mode selection capability. The resulting in-plane displacement field spectra were measured using a Doppler laser vibrometer and acquired via an oscilloscope. The electrical signal triggering, laser scanning, and data acquisition processes during the experiment were automatically controlled by a LabVIEW program on a laptop computer.

Test Results: The theoretical results were in good agreement with the experimental findings. The designed omnidirectional high-order SH guided wave transducer successfully excited the target SH guided wave mode while effectively suppressing the generation of other SH guided wave modes. This advancement facilitates the application of high-order SH guided waves in structural tomography.

Figure: ATA-2021B High-Voltage Amplifier Specifications and Parameters