Numerical Simulation of Guided Ultrasonic Waves in Fiber Metal Laminates including Model Reduction Methods
Fiber metal laminates (FML) offer substantial reduction in structural weight along with excellent fatigue strength. However, FML are very sensitive to delaminations that are usually not detectable by visual inspection. Here, SHM with guided ultrasonic waves is potentially suitable for damage detection by using the physical phenomena of wave propagation interacting with structural defects.The presented works combines the efforts of numerical simulation and model reduction methods to allow time and cost-efficient simulations of the wave propagation in FML as well as a post processing by inverse methods. Based on an already existing 2D-model a 3D finite element model is developed involving the excitation of waves and observing its propagation. One crucial aspect here is the model discretization and hence, the corresponding element size. To validate the numerical model the wave propagation and the resulting displacement field are compared to analytical solutions derived from the dispersion relation.Furthermore, a model-based inverse solution in a stochastic framework is described for the damage detection, localization and characterization with the aid of a simpler case study on 2D elastic wave equation. The inference problem uses a projection-based reduced-order model rather than the high-fidelity model in order to significantly reduce the computational costs.