基于谱元法的板结构中导波传播机理与损伤识别

建立板结构的三维谱元法模型和结构-压电晶片耦合模型，对铝合金板中Lamb波的传播机理和与损伤作用规律进行研究。以单点激励力模型研究了板中Lamb波的频散关系，从理论上对所建立的模型进行了验证；基于压电晶片模型研究了在施加电压激励条件下导波的传播规律；研究单一压电晶片、板中上下表面施加同相位或反相位激励电压的两个压电晶片三种情况下结构的响应；对板中传播Lamb波的幅值与传播距离的关系进行分析；采用减小结构单元刚度的方法模拟结构中的裂纹损伤，研究Lamb波与损伤的作用；结合试验分析，验证所仿真结果结论的正确性。相对二维谱元法模型，所建立的板结构三维谱元法模型能更真实地模拟结构中导波的激励与接收以及波的传播。

Guided Wave Propagation Mechanism and Damage Detection in Plate Structures Using Spectral Element Method

A three-dimensional spectral element method (SEM) model including piezoelectric (PZT) structure coupling model for characterizing wave propagation in plate structures is developed. Characteristics of wave propagation in an isotropic aluminum alloy plate are therefore investigated. Dispersion relation of Lamb waves are studied by adding excitation force at the plate, so as to verify the simulated model. Characteristics of wave propagation under three excitation cases, i.e. one PZT disc, two PZT discs bonded on opposite sides of the plate with same and reverse excitation phases, are discussed. The damage in the plate structure is modeled by reducing the stiffness of the plate and wave interaction with damage is discussed. The conclusions and the proposed coupled PZT disc-structure model are validated by using experiments and the results demonstrate that the proposed three-dimensional SEM model can effectively and realistically simulate the excitation and capture of the responses of the structures, as well as wave propagation in structures, in comparison with two-dimensional SEM model.