In-plane selective excitation of arbitrary vibration modes using thickness-shear (d 15) piezoelectric transducers

Experimental modal analysis is of great importance for the dynamic characterization of structures. Existing methods typically employ out-of-plane forces for excitation and measure the acceleration or strain for modal analysis. However, these methods encountered difficulties in some cases. In this work, we proposed an in-plane excitation method based on thickness-shear (d (15)) piezoelectric transducers. Through the combination of distributed d (15) PZT strips, arbitrary vibration modes can be selectively excited in a wide frequency range. Both simulations and experiments were conducted and the results validated the proposed method. Specifically, bending, torsional, and longitudinal vibration modes of a rectangular bar were selectively excited. Torsional modes of a shaft were excited without the aid of brackets and bending modes of a circular plate were excited with actuators placed at nodal lines. Furthermore, the electromechanical impedance of the PZT-structure system was measured from which the natural frequency and quality factor were directly extracted. Due to its simplicity and flexibility, the proposed vibration excitation method is expected to be widely used in near future.

Automated summary

Experimental modal analysis plays a crucial role in studying the dynamic properties of structures. This study proposes an in-plane excitation method using thickness-shear piezoelectric transducers, allowing selective excitation of various vibration modes. The method's effectiveness is validated through simulations and experiments, and the natural frequencies and quality factors are extracted by measuring the electromechanical impedance of the system.