Research on Piezoelectric Impedance Technology for Bolt Health Monitoring

The purpose of this paper is to demonstrate experimentally the feasibility of structural incipient health monitoring through the admittance measurement of piezoelectric patches bonded to the structure. The incipient damage, loose of a bolt in a beam was given as an example. In low frequencies domain and high frequencies domain, the piezoelectric admittance was measured when the bolt was loose. The results show the loose of the bolt causes the obvious variations of the admittance in high frequency domain. But in low frequency domain, the change of the piezoelectric admittance is only limited. Thus, the change of piezoelectric admittance can give a scale for structural health monitoring in high frequency domain.