Electro-mechanical impedance model of a laminated rectangular plate with imperfect interfaces

A laminated orthotropic rectangular plate surface-bonded or embedded with a piezoelectric actuator/sensor is investigated based on the state-space approach. A linear spring-like model is utilized to simulate the interfacial imperfections. Besides, to establish the global transfer relations between the elastic variables of the elastic layers and the piezoelectric films, a matrix reduction technique is employed. Then, an analytical expression of electro-mechanical impedance, which contains the information of the interfacial bonding, is derived based on the three-dimensional theory of elasticity (or piezoelasticity). Numerical results show that the signals extracted from the present electro-mechanical impedance model can detect the interfacial conditions of laminates, and hence, the present analysis provides an efficient and convenient approach to monitor the interfacial defects in the laminated structures.