Laminated Piezoelectric Sensors for Structural Health Monitoring: Interphase Degradation Effects

Laminated piezoelectric composites are widely used as smart materials due to their outstanding performance in sensing, actuating, and energy harvesting, especially in the aerospace, automotive, and medical industries. However, their structural integrity and reliability are often compromised by delamination. This research investigates the combined influence of delamination and interphase degradation on laminated piezoelectric composites. Using a multidisciplinary strategy that integrates analytical techniques with numerical simulations, the present investigation simulates the mechanisms responsible for accelerated delamination under interphase degradation. A two-scale asymptotic homogenization method (AHM) is employed to determine the effective piezo-electromechanical properties, while finite element analysis (FEA) with periodic boundary conditions provide accurate and realistic simulation results. Results show that progressive interphase degradation can reduce the effective stiffness by up to two orders of magnitude and substantially decrease the piezoelectric coupling, while the dielectric response remains nearly constant. These findings emphasize the crucial role of the interphase in the electromechanical behavior of smart composites and its incorporation into Structural Health Monitoring (SHM) frameworks for enhanced reliability and predictive accuracy.