Constrained thickness-shear vibration-based piezoelectric transducers for generating unidirectional-propagation SH₀...

Area of Science:

• Materials Science
• Mechanical Engineering
• Nondestructive Testing

Background:

• Exciting pure guided waves with controllable wavefields is crucial for structural health monitoring (SHM).
• Existing transducers struggle to generate unidirectional guided waves, limiting SHM's effectiveness.
• Unidirectional waves simplify signal interpretation by preventing unwanted reflections.

Purpose of the Study:

• To investigate piezoelectric wafer transducer characteristics for exciting unidirectional guided waves.
• To develop novel piezoelectric transducers capable of generating pure unidirectional shear horizontal (SH0) waves.
• To validate the performance of the developed transducers through simulations and experiments.

Main Methods:

• Theoretical modeling and numerical simulations of piezoelectric transducer vibration.
• Analysis of phase differences between electrical excitation and mechanical response.
• Design and fabrication of two novel piezoelectric transducer configurations.
• Finite element simulations and experimental validation of transducer performance.

Main Results:

• A tunable phase difference was identified between the PZT wafer excitation and adhesive layer response.
• Two transducer designs were proposed and demonstrated to excite unidirectional SH0 waves.
• The developed transducers enhance wave energy propagation in a single direction without time delay.
• Experimental results confirmed the excitation of pure SH0 waves.

Conclusions:

• Novel piezoelectric transducers can effectively generate unidirectional SH0 waves.
• The simple configuration of these transducers offers significant potential for SHM applications.
• These transducers address the need for improved guided wave generation in SHM.