NONDESTRUCTIVE EVALUATION OF MATERIALS USING AN INSERTED PIEZOELECTRIC SENSOR - CORRELATION WITH HARDNESS MEASUREMENTS

Using a one-dimensional model, we show that the analytical expression of the electric impedance of a piezoelectric ceramic is function of the acoustic properties of the medium surrounding it, The validity of this model is displayed by comparing simulated and experimental data, Then, numerical treatments are developed for processing the ceramic electric impedance in order to determine the acoustic properties of the medium surrounding the ceramic. This method is applied to monitor polymerization processes and the validity of the technique is shown from the comparison of the results it gives with those resulting from traditional Barcol hardness measurements.