Diagnostic Lamb waves in an integrated piezoelectric sensor/actuatorplate: analytical and experimental studies

Abstract

The objective of this study is to model the diagnostic transient waves in anintegrated piezoelectric sensor/actuator plate with a view to using it as a first steptowards establishing an entire structural health monitoring system and toprovide experimental verification of the proposed models. PZT ceramic disksare surface mounted on an aluminum plate acting as both actuators and sensorsto generate and collect A0 mode Lamb waves. Mindlin plate theory is adopted tomodel the propagating waves by taking both transverse shear and rotary inertiaeffects into account. Actuator and sensor models are both proposed. Theinteraction between an actuator and the host plate is modeled based on classicallamination theory. The converse piezoelectric effect of the actuator istreated as an equivalent bending moment applied to the host plate. The sensoracts as a capacitor that converts the sensed strain change into a voltageresponse. An analytical expression for the sensor output voltage in terms ofthe given input excitation signal is derived, and then experimental work isperformed to verify the accuracy of the analytical model. Experimental resultsshow that single-mode Lamb waves in the plate can be successfully generatedand collected through the integrated PZT disks. The experiment also shows thatthe predicted sensor output for both amplitude and phase agrees well withexperimentally collected data.