The Study On The Structural Damage Identification Using Lamb Waves Based On Intelligent Piezoelectric Materials

With the rapid development of science and technology, a large numbers of large-scale engineering structures and mechanical structures are much widely used.Due to the complex working environments and the continuous production process with high-strength, the much more stringent requirements to the structural stability and safety are presented. The technology of structural health monitoring and structural damage identification is of great significance for timely detecting and finding the structural damage and predicting the development of damage, and it is efficient to avoid safety accidents which lead to property damage and casualtiesIn this paper, the structural damage identification with the method of Lamb waves based on smart piezoelectric materials is studied. Firstly, the dispersion characteristics of Lamb waves are proposed. The Rayleigh-Lamb equation of Lamb waves has been deduced, and the Rayleigh-Lamb equation is numerically simulated and the dispersive curves are presented. The relationships between the group velocity and frequency-thickness of A0 and S0 modes are determined, which is the basis of structural damage identification using Lamb waves.And then, the mode shapes of smart piezoelectric materials, PZT, are simulated and analyzed using ANSYS, and therefore the best central frequency of excitation signals of Lamb waves is determined. In combination with the simulation results using MATLAB and ANSYS, the corresponding parameters of the excitation signals are selected.Finally, using the PZT as the exciter and receiver of Lamb waves, the experiments of structural damage identification using Lamb waves is presented, and the damage location by means of Lamb waves is realized. In the experiments, the experimental platform is setup and the experimental control system is designed based on Lab VIEW,and the simultaneous trigger of Lamb waves excitation and data acquisition is realized.In the experimental study, the damage identification focused on the aluminum plateswith health status, artificial slot damage status and artificial borehole damage status is presented respectively. By using the data process techniques, such as wavelet analysis,the experimental data is processed, and the propagation time of Lamb waves is obtained, and the propagation distance is calculated to find the damage location. As well, the waveform information of different damage types and degrees are compared and analyzed.In the experiment, the structural damage location using Lamb waves based on the smart piezoelectric materials is realized, and then the different damage types and degrees are briefly analyzed, and the further in-depth study is prepared.