TY - THES A1 - Lugovtsova, Yevgeniya T1 - Damage detection in multi-layered plates using ultrasonic guided waves N2 - This thesis investigates ultrasonic guided waves (GW) in multi-layered plates with the focus on higher order modes. The aim is to develop techniques for hybrid structures such as of adhesive bonds and composite pressure vessels (COPV) which are widely used in automotive and aerospace industries and are still challenging to inspect non-destructively. To be able to analyse GW, numerical methods and precise material properties are required. For this purpose, an efficient semi-analytical approach, the Scaled Boundary Finite Element Method, is used. The material properties are inferred by a GW-based optimisation procedure and a sensitivity study is performed to demonstrate the influence of properties on GW. Then, an interesting feature, called mode repulsion, is investigated with respect to weak and strong adhesive bonds. The results show that the coupling between two layers influences the distance between coupled modes in a mode repulsion region, thus allowing for the characterisation of adhesive bonds. At next, wave-damage interaction is studied in the hybrid structure as of the COPV. Results show that the wave energy can be concentrated in a certain layer enabling damage localisation within different layers. Further investigations are carried out on the hybrid plate with an impact-induced damage. Two well-known wavenumber mapping techniques, which allow to quantify the damage in three dimensions, are implemented and their comparison is done for the first time. KW - Lamb waves KW - Composites KW - Structural Health Monitoring KW - Inverse procedure KW - Scaled Boundary Finite Element Method PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:bsz:291--ds-382863 DO - https://doi.org/10.22028/D291-38286 SP - 1 EP - 131 PB - SciDok - Der Wissenschaftsserver der Universität des Saarlandes CY - Saarbrücken, Germany AN - OPUS4-57058 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -