The Finite Element Analysis Of Damage Identification Based On Piezoelectric Impedance

In recent years, natural disasters occurred frequently. Structural damage degree detection technology has accepted a great challenge. Like the damage of post-disaster buildings, the damage of machinery equipment and so on. In the practical life, the accident which caused by equipment's hidden damage is common. Therefore, the people are also getting higher and higher to the safe demand. Structural damage identification and health monitoring technology has also been growing attention. Currently, piezoelectric impedance identification and health monitoring technology has been done a lot of related research in the domestic and foreign scholars. Based on the basis of previous studies, this paper will carry on further study of the technology by theoretical deducing, finite element analysis (FEA), experiment and data processing method. The research content and achievement is as following:1. The basic information of the piezoelectric materials is introduced. Piezoelectricity-structure coupled system's electric impedance theory is analyzed. And the piezoelectric coupling impedance/admittance formula is deduced. The relationship between mechanical impedance and piezoelectricity-structure coupled system's electric impedance is analyzed for damage identification and health monitoring technology.2. The mechanical impedance/admittance formula of aluminum beam is deduced. The relationship between mechanical impedance and piezoelectricity-structure coupled system's electric impedance is further analyzed from the perspective of FEA. The correctness of FEA is verified by experiment. The results indicate that: piezoelectric coupling impedance and the mechanical impedance are completely consistent by the resonant frequency and vibration model. It is confirmed that the relationship between mechanical impedance and piezoelectricity-structure coupled system's electric impedance that the change of piezoelectric coupling electricity impedance is the direct-viewing reflection of mechanical impedance change.3. The impedance theory of single PZT piece is deduced. ANSYS finite element software is applied on the simulation analysis of PZT piece. Compared with experiment results which gets the linear frequency range and chooses the appropriate frequency sector in the linear frequency range as the range of damage detection. Taken the effect of piezoelectric coupling impedance which is influenced by the crack number, crack depth, crack position of aluminum beam and the PZT piece's position as the study object. Carries on finite element analysis of PZT-aluminum beam's coupling electric impedance. The results show that: regarding crack number's increase is more obvious in the impedance spectrum's change, but using the data processing method is difficult to identify the damage. It is more effective for crack depth, crack positions and the position of PZT piece. With the crack depth increases, the damage index increased. The closer distance between the crack and PZT is, the more effective PZT piece identify.4. To verify the effectiveness of FEA damage detection results. To build the experimental platform and use British WK6500B impedance analyzer to conduct experimental research. The results show that:experimental damage detection results and finite element simulation results are completely consistent, which provides effective research means for the quantitative measure and the location identification of the damage.Figure 66 Table 11 Reference 82...