Three-dimensional scaled boundary finite element method to simulate Lamb wave health monitoring of homogeneous structures: Experiment and modelling

Exploiting scattering and reflection related data of ultrasonic Lamb wave interactions with damage is a common approach to health monitoring of thin-walled structures. Using thin PZT sensors, the method can be implemented in real-time. Simulation of Lamb wave propagation and its interaction with damage plays an important role in damage diagnosis and prognosis. It is, however, a time-consuming task due to the high-frequency waves that are commonly used to detect tiny damage. The current study employs the Scaled Boundary Finite Element Method (SBFEM) for effective modeling of Lamb wave health monitoring of homogenous thin plates. The electromechanical effects of piezoelectric sensors are included in the model to improve accuracy and make the results comparable to those of laboratory experiments. Simple meshing of complex topologies is possible by converting standard finite elements to scaled boundary elements. The 3D SBFEM wave motion equations are solved in the time domain to capture the sensor's PZT response to a high-frequency tone-burst actuation. The results are validated by pitch-catch and pulse-echo laboratory tests carried out on thin plates. SBFEM is used to study wave propagation in complex configurations, such as a stiffened plate, and the results are compared to their FEM counterparts. According to the findings, SBFEM significantly reduces the computational costs associated with simulation of Lamb wave health monitoring while also providing significant accuracy in comparison to the experimental results.