Equivalent Parameters of Embedded PZT Elements for Concrete Structure Monitoring

The characteristics of a PZT ceramic element embedded in concrete are studied in this article. Based on the theory that the material coefficients of ceramic change their values under different stress levels, a method of measuring concrete stress by detecting the characteristics of the embedded ceramic element is proposed. The experiment uses a network analyzer to monitor some physical parameters of the piezoelectric element during the loading cycle in which the loads are applied on a concrete specimen with an embedded PZT ceramic. In order to describe the characteristic change from the aspect of energy losses, three dissipation factors are also obtained from the piezoelectric equations. The experimental results show that although some equivalent parameters show a better monotonicity, the measurement error analysis indicates that such monotonicity is not reproductive. The piezoelectric dissipation factor performs a relatively good monotonicity and reproducibility, and is recommended to be taken as the stress indicator for the stress measurement.