Numerical study of guided waves generated by a thin PZT disk embedded into a laminated composite plate

The development of a Structural Health Monitoring (SHM) system based on ultrasound guided waves often relies on numerical models to determine the appropriate placement or number of sensors or study influential parameters, as an alternative to numerous experiments. The accurate and fast modeling of both actuator/sensor response and wave propagation is thus essential. This paper focuses on efficiently modeling a PZT actuator embedded in a laminated composite plate for guided wave SHM, since such actuation has been scarcely studied so far. Firstly, a multiphysics finite element model is conceived and validated through comparison with experiments. Secondly, a potential simplification of the model based on the well-known pin-force model is studied but fails to represent the actual stress source in the particular case of an embedded PZT actuator. Therefore, a hybrid approach is proposed. It consists of first computing the effective loading induced by an embedded PZT into a composite plate using the multiphysics model and then applying this loading in a purely mechanical model. The features of the guided wavefield simulated with this approach are in good agreement with those simulated with the multiphysics one at low frequencies. Limitations of the approach for higher frequencies are discussed.