Optimal measurement setup for damage detection in piezoelectric plates

An optimization of the excitation–measurement configuration is proposed for the characterization of damage in PZT-4 piezoelectric plates, from a numerical point of view. To perform such an optimization, a numerical method to determine the location and extent of defects in piezoelectric plates is developed by combining the solution of an identification inverse problem, using genetic algorithms and gradient-based methods to minimize a cost functional, and using an optimized finite element code and meshing algorithm. In addition, a semianalytical estimate of the probability of detection is developed and validated, which provides a flexible criterion to optimize the experimental design. The experimental setup is optimized upon several criteria: maximizing the probability of detection against noise effects, ensuring robust search algorithm convergence and increasing the sensitivity to the presence of the defect. The measurement of voltage ϕϕ is concluded to provide the highest identifiability, combined with an excitation of the specimen by a mechanical traction transverse to the polarization direction. Sufficient accuracy is predicted for the damage location and sizing under realistic noise levels.