ABSTRACT
As a kind of common structure, aluminum plate is widely used in engineering, especially in the manufacture of aircraft, vessels, and many other structures in various fields. It has a very important significance to monitor the working state of aluminum plate structures over time. At present, ultrasonic Lamb wave Nondestructive Testing (NDT) technology is widely applied in the health monitoring of aluminum plate structures (Wang 2007, Liu 1999). Recently, more and more people use finite-element software for the simulation of Lamb wave detection of aluminum plate (Xu 2015); however, in the present simulation analysis, most of the analysis methods are directly exciting and extracting the Lamb wave displacement signal on the structure surface, which still have a certain difference with the actual experiment using the sensor to detect the aluminum plate, especially the influences of adhering layers on the transformation between electric voltage and structural movement, resulting in a great difference between numerical simulation using equivalent displacement input and output and experimental results. Accordingly, in this paper, on the basis of the research of the existing active Lamb wave detection (Yan & Zhang & Meng 2010, Cao 2008, Yan et al 2013), using finite-element software ABAQUS and considering the influence of PZT polarization direction and the detection wave spectrum characteristics
2.2 Model establishment
The aluminum plate and PZT patch models provided by ABAQUS and used in this paper are the shell elements. They use the solid element and the piezoelectric element, respectively. The size of the aluminum plate model is 80 mm × 80 mm × 1 mm, and the size of the piezoelectric patch element is 12 mm × 6 mm × 1 mm. The distance between driver (PZT1) and receiver (PZT2) is 480 mm, and the distance between the exciter and the left boundary is 160 mm along the horizontal direction, and the distance between the exciter and the right boundary is also 160 mm, as shown in Figure 4. The parameters of the materials are shown in Tables 1-2.
