Finite-dimensional piezoelectric transducer modeling for guided wave based structuralhealth monitoring

Abstract

Among the various schemes being considered for structural health monitoring (SHM),guided wave (GW) testing in particular has shown great promise. While GW testing usinghand-held transducers for non-destructive evaluation (NDE) is a well establishedtechnology, GW testing for SHM using surface-bonded/embedded piezoelectric wafertransducers (piezos) is relatively in its formative years. Little effort has been made towardsa precise characterization of GW excitation using piezos and often the variousparameters involved are chosen without mathematical foundation. In this work, aformulation for modeling the transient GW field excited using arbitrary shapedsurface-bonded piezos in isotropic plates based on the 3D linear elasticity equations ispresented. This is then used for the specific cases of rectangular and ring-shapedactuators, which are most commonly used in GW SHM. Equations for the outputvoltage response of surface-bonded piezo-sensors in GW fields are derived andoptimization of the actuator/sensor dimensions is done based on these. Finally, numericaland experimental results establishing the validity of these models are discussed.