On the design of a piezoelectric self-sensing smart composite laminate

The structural health monitoring of composite laminates is a rapidly emerging need in structural applications. Different real-time sensors integrated into laminates have been proposed, such as fiber Bragg gratings and piezoceramics. However, their presence negatively affects the mechanical properties of the hosting laminate. This work proposes a non-invasive method for piezoelectric functionalization of composite laminates by interleaving lead zirconate titanate micrometric powder between glass-fiber-reinforced polymer plies. The effects of different powder volume fractions on the electromechanical properties were evaluated in terms of the electrical response and laminate inherent strength. The lead zirconate titanate powder laminates demonstrated an electrical sensitivity value that was up to 439% higher compared with that of the embedded commercial disk laminate (12.4 V/kN versus 2.3 V/kN). Impact tests revealed that the resistance of the interleaved lead zirconate titanate powder laminates is comparable to that of the pristine laminates, whereas a fragile commercial disk leads to delamination. Furthermore, an analytical model was proposed to predict the piezoelectric voltage coefficient g33 as a function of the electrical properties, volumetric powder fractions, and polarization process. The model matched the experimental g33 coefficients (R2=0.97), demonstrating its capability to predict the electromechanical behavior of piezoelectric composites and define their design guidelines.