In-plane selective excitation of arbitrary vibration modes using thickness-shear (d15) piezoelectric transducers

TL;DR

This paper introduces an in-plane excitation technique using thickness-shear (d15) piezoelectric transducers that enables selective excitation of various vibration modes in structures, validated through simulations and experiments.

Contribution

The study presents a novel in-plane excitation method with d15 PZT transducers for selective vibration mode excitation, overcoming limitations of traditional out-of-plane methods.

Findings

Successfully excited bending, torsional, and longitudinal modes

Achieved mode excitation without brackets or at nodal lines

Extracted natural frequency and quality factor from impedance measurements

Abstract

Experimental modal analysis (EMA) 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 (d15) piezoelectric transducers. Through the combination of distributed d15 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.