Modal Parameters Identification of Concrete Structure Based on Built-in PZT Sensors

Abstract

Structural modal parameters identification so far has been a major issue in health monitoring system, for which damage diagnosis methods are based on. The emergence and development of smart materials have provided the more accurate techniques in structural parameters measurement. Piezoceramic material has the advantages of cheap, wide band frequency response and high sensitivity to strain variation. In this paper, PZT sensors encapsulated by cement were firstly made and the dynamic performance test proceeded on the MTS. Embedded into concrete pillar, the sensors can identify the vibration parameters of structure based on the direct piezoelectric effect. Impact test result shows that the PZT sensors signal can correctly render the regular pattern of the damped natural vibration of structure. So the modal parameters can be identified by the PZT sensors signal. Introduction Piezoelectric ceramic materials, such as Lead Zirconate Titanate (PZT), with functions of both sensing and actuating have become one of the potential smart materials for use in structural health monitoring and control of civil structures. Structural health monitoring and damage detection based on piezoelectric ceramic material has become one of the most important research topics since PZT has distinct advantages, such as quick response, broadband frequency and low price, among others, over traditional sensor materials. The piezoelectric-based health monitoring methods can be classified into two major groups: the passive sensing methods and the active sensing methods. According to the character of the PZT material, the former method mostly focuses on the monitoring of impact loads using the direct piezoelectric effect. The latter again can be sorted into three aspects, namely, the impedance-based method, the vibration-characteristic-based method and the Lamb-wave-based method (Song et al., 2004) in which monitoring is carried out by analyzing the variation of the high-frequency elastic waves generating by the PZT sensor. Although the two modes health monitoring methods based on PZT are respectively with its own advantage, the former could response the structure deformation without active excitation source which is more adaptable for monitoring structure in dynamic pattern especially for structure in a natural disaster. Furthermore, for civil structures of low natural frequency, passive monitoring method can save the