Ultrasonic Guided Waves Simulation in SHM Design – Finite Element Modeling and Model Data Handling

Kurzfassung

Over the last years a lot of scientific work has been done regarding structural health monitoring (SHM) systems. Introducing SHM systems offer the possibility of saving weights going along with other advantages, e.g. an improved condition-based maintenance of the structure, decreasing fuel consumption. In case of thin-walled lightweight structures as they are used for aerospace applications SHM concepts based on ultrasonic guided waves are very promising. The large experimental effort of designing such SHM systems can be significantly reduced by accompanying simulations. Simulation techniques to analyze the guided wave propagation have been developed using different numerical methods, e.g. conventional and higher order finite element methods(FEM), elastodynamic finite integration technique (EFIT), finite cell methods. To investigate the static and dynamic behavior of thin-walled lightweight structures shell-type finite element models are widely used. For general purpose SHM simulations it is advantageous to employ these models also to analyze wave propagation phenomena without switching to a special tool. Only few modifications regarding mesh refinement are needed. Therefore, we present a strategy to simulate the guided wave propagation in layered composite structures by using finite shell elements of Reissner-Mindlin type. The results are benchmarked with experimental data coming from the Open Guided Waves project (http://openguidedwaves.de/). The usability of such simulations as well as the comparison with experimental data is simplified by easy access to the results in a standardized data format using open-source tools. Thus, we particularly focus on aspects of model and result data handling, post-processing and visualization. The implementations presented here are based on the recently introduced FE data standard VMAP (www.vmap.eu.com). The approach enables the combination of simulation data in a central data container coming from different analysis tools. It yields to an improved evaluation of the proposed SHM system and allows the direct comparison with experimental data.