Gonenli, Can2023-01-122023-01-1220222523-39202523-39392523-39202523-3939https://doi.org/10.1007/s42417-022-00476-1https://hdl.handle.net/11454/76354Purpose Various damages directly affect the dynamic characteristics of engineering structures, and it is necessary to create a reliable model against the negative consequences of the possible effects of these damages. In this study, damage behaviour is investigated to identify weak points of structures in terms of free vibration response and mode shape. Method The classical plate theory is employed to investigate the weak points of the three different plate frame structures due to the presence of the cut-out in different locations. ANSYS and SolidWorks are used to validate the reliability of the present model. The free vibration analysis is performed separately by changing every single healthy element stiffness matrix to a damaged one to obtain a unique special damaged global stiffness matrix based on each damage location. Results The cut-out affects the natural frequency more at the curl zones of the relevant mode shapes. In regions that are not affected by the mode shape, the effect of the cut-out is minor or not. Conclusion While this study highlights the weak points of structures under dynamic load, it also paves the way for reverse engineering methods for damage detection.en10.1007/s42417-022-00476-1info:eu-repo/semantics/closedAccessPlate frame structureFree vibration analysisCut-outFinite-element analysisThin plateFree-Vibration AnalysisCracked Rectangular PlateFinite-ElementThicknessStabilityArticle10415991611WOS:0007772287000012-s2.0-85127606809Q2Q2