TY - CONF A1 - Bulling, Jannis A1 - Franosch, Georg A1 - Lugovtsova, Yevgeniya A1 - Prager, Jens ED - Rizzo, P. ED - Milazzo, A. T1 - Sensitivity of Ultrasonic Guided Waves to Elastic Constants: A Numerical Study N2 - The dispersive properties of Lamb waves can be utilised for material characterisation because the frequency-wavenumber-relationship, as well as the group velocity, depend on material parameters. These dependencies make a non-destructive estimation of an elastic constant possible. This preliminary study investigates the sensitivity of dispersion curves caused by a change in elastic constants. The Scaled Boundary Finite Element Method is used to compute special dispersion curves, which show the sensitivity value of the frequency and group velocity as a colour value. This representation allows for easy identification of patterns and local effects. Two sets of dispersion curves are presented, one set for a steel plate and the other set for a plate made of a carbon fibre reinforced polymer. In general, we notice that the sensitivity often increases with the frequency and that higher-order modes seem to be more suitable for material characterisation. Moreover, specific modes respond to material changes while others are relatively unaffected, which must be taken into consideration for material characterisation. T2 - European Workshop on Structural Health Monitoring (EWSHM 2020) CY - Online meeting DA - 06.07.2020 KW - Scaled Boundary Finite Element Method KW - Lamb waves KW - Dispersion curves KW - Carbon fibre reinforced polymer KW - Transverse isotropy PY - 2021 SN - 978-3-030-64593-9 DO - https://doi.org/10.1007/978-3-030-64594-6_73 VL - 127 SP - 759 EP - 768 PB - Springer CY - Cham AN - OPUS4-51986 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nicolai, Marcel A1 - Bulling, Jannis A1 - Lugovtsova, Yevgeniya A1 - Zeipert, Henning A1 - Prager, Jens A1 - Henning, Bernd ED - van Keulen, Wim ED - Kok, Jim T1 - On the repulsion effect of coupled Lamb wave modes N2 - Lamb waves, recognized for their significance in material characterisation, structural health monitor-ing, and non-destructive testing, exhibit complex behaviours that are crucial for industrial applica-tions. This paper delves into the mathematical and physical principals of the repulsion effect that can be observed in the dispersion curves of coupled Lamb wave modes. This effect is the result from the mechanical coupling of thin-walled solid plates and prevents the crossing of the dispersion curves. The study employs the Scaled Boundary Finite Element Method to calculate the dispersion curves of coupled plates and to simulate their interaction for a weak and ideal coupling. Through a mathemati-cal framework and a physical analogy with simple harmonic oscillators, the paper elucidates the un-derlying principals of this effect. Furthermore, the paper highlights the practical significance of the repulsion effect in Lamb waves, suggesting its application for testing and monitoring the integrity of multi-layer structures like adhesive bonds, which are important for various industrial applications. A deepened understanding of this effect could contribute to the enhancement of non-destructive evalua-tion techniques. T2 - ICSV 2024 CY - Amsterdam, The Netherlands DA - 08.07.2024 KW - Scaled Boundary Finite Element Method (SBFEM) KW - Lamb waves KW - Mode repulsion KW - Mechanical coupling KW - Dispersion curves PY - 2024 SN - 978-90-90-39058-1 SN - 2329-3675 SP - 410 EP - 418 PB - The International Institute of Acoustics and Vibration (IIAV) CY - Amsterdam AN - OPUS4-62855 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nicolai, Marcel A1 - Bulling, Jannis A1 - Lugovtsova, Yevgeniya A1 - Zeipert, Henning A1 - Prager, Jens A1 - Henning, Bernd T1 - On the repulsion effect of coupled Lamb wave modes N2 - This work investigates the phenomenon of mode repulsion in coupled Lamb wave systems. By mechanically coupling two dissimilar plates using spring elements, it is shown that previously intersecting Lamb wave modes are repelled, avoiding any crossing in the dispersion curves. The effect, rooted in eigenvalue theory and first observed in quantum systems, is explained through both mathematical models and classical analogies with coupled harmonic oscillators. Numerical simulations using the Scaled Boundary Finite Element Method validate the theoretical predictions, revealing a correlation between strain distribution and frequency splitting. The observed mode repulsion provides new insights into interface properties and offers potential for applications such as monitoring adhesive degradation in layered structures. T2 - DAGA 2024 CY - Hannover, Germany DA - 18.03.2024 KW - Scaled Boundary Finite Element Method (SBFEM) KW - Lamb waves KW - Mode repulsion KW - Mechanical coupling KW - Dispersion curves PY - 2024 SP - 632 EP - 635 AN - OPUS4-62854 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -