Optimal Sensor Placement for Damage Characterization Using Genetic Algorithms

Abstract

The optimal placement of sensors is a critical issue in detecting damage in laminated composite structures. The goal is to use a minimum number of sensors, placed at the right locations, so that the voltage signals received from the sensor set can be used to detect both presence and extent of damage. In this study, an optimization procedure is developed using Genetic Algorithm (GA) to determine the number and location of piezoelectric sensors for detection of seeded delaminations in composite plates. The analysis is based on a refined layerwise theory; capable of modeling ply level stresses, and the presence of seeded delaminations are modeled using Heaviside step functions. A two-way coupled electromechanical coupled field formulation is used to describe the induced strain. A damage index formulated using the difference in voltage signals, caused by the local changes in the strain induced by the presence of delamination, is used as the objective function. The results obtained from simulations are verified through numerical simulation as well as with experimental results obtained using customized piezoelectric sensors and a Laser Scanning Vibrometer. The optimum sensor pattern is capable of detecting discrete seeded delaminations in thick composite plates.