Piezoelectric Sensing of Rigid-Flexible Coupled Free-Edge Rectangular Plates

With the rapid development of space technology, rigid-flexible coupling systems are widely used in aerospace structures. Attitude-vibration coupling control requires a deep understanding of the rigid-flexible coupling dynamics of these systems. In the presented work, a center rigid body coupled with a rectangular thin plate was studied. The dynamic equation derived based on Hamilton′s principle of the rigid-flexible couple structure was introduced, and the direct piezoelectric effect was introduced to detect the sensing signal of the dynamic behavior of the flexible thin plate to reveal the rigid-flexible coupling effect. In case studies, the dynamic response of the rigid-flexible couple thin plate was investigated, the modal sensing signal generated by the piezoelectric patch, and the sensing signal induced by rigid body motion were explored with various piezoelectric sensor positions, sensor size, rigid-flexible coupling characteristics, and mechanical excitation properties. Analysis showed that piezoelectric sensor signals varied with sensor position, primarily governed by modal shape functions. But in rigid-flexible coupled systems, external excitation also significantly impacts piezoelectric sensor effectiveness. With increasing the rigid body inertia, the output signal could decrease greatly, whereas greater mechanical excitation amplifies it. Notably, moment-induced rotation generates substantially stronger signals than force-induced translation, highlighting the system′s dynamic complexity.