Numerical Investigations on the Influence of Prestress on Lamb Wave Propagation

The use of Lamb waves for the determination of component states and damage detection in thin-walled structures is a generally accepted method in today’s Structural Health Monitoring. Although the behavior of Lamb waves has been dealt with in depth, there are still topics where research is needed, for example, the influence of prestress on Lamb wave propagation. In order to gain profound insight into this area, experimental methods and results on wave propagation under the influence of prestress have been presented in previous work by the authors. These results are characterized by the use of a 2d Fourier transform to evaluate the observation of this behavior over large frequency ranges. Based on these results, the work presented here deals with a 2d numerical modeling approach of the wave propagation in a prestressed structure. The focus is on analyzing the suitability of linear and non-linear material models for reproducing the wave velocity changes. For this purpose, the numerically obtained results for different material models are compared with experimental data. The numerical data is generated using a FE model which combines a nonlinear static computation for the prestress and a linear eigenfrequency computation for the dispersion behaviour of Lamb waves. Finally, the comparison of simulated and experimental data will provide a well-founded basis for further numerical analysis on this topic.