Piezoelectric-ceramic-embedded smart concrete module for structure health monitory

A smart concrete module with embedded PZT ceramic element is proposed to monitor the health of the structure. Being embedded, the PZT ceramic is in a complicate environment which results in the changes of physical properties of PZT element. In this paper, a new method of measuring energy losses is first proposed to evaluate the effect of such physical changes. In order to measure the energy losses, the corresponding dissipation factors are calculated from the piezoelectric equivalent parameters. In the stress and temperature experiments, two kinds of PZT ceramic perform different features which also result in changes of energy losses. It is also found that when the environment temperature is unstable, the changes of the equivalent parameters are in fact the results of both the effects of stress and temperature. However, comparing the stress with temperature experimental results, it is found that the eigen frequencies of the embedded piezoelectric ceramic perform special characteristics that they are more sensitive to temperature than to stress. It enables us to solve the problem of the stress and temperature cross sensitivity.