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Stress concentrations typically exist around the perimeter of an opening and on attached structures, thereby resulting in a potential risk of crack initiation. Experimental and numerical methods on stress concentration distribution analysis can be applied in this study. This study reveals the differences in stress concentration distributions around various types of slots. Typical slots have been selected to discuss the influence on stress concentration distribution when the connections of flat bar and connection plate are considered. This concept is novel given the experiments conducted and finite element method (FEM) results found under complex loads. The FEM is used to compare calculated results with experimental data, and continuous plotting of numerical results can verify the outcomes. The results show the stress concentration distribution around the selected slot edge, where peak stress appears around the openings of different types of slots.

The design of lifting blade shapes is a key engineering application, especially in domains such as those of marine propellers, hydrofoils, and tidal energy converters. In particular, the excitation frequency must be different from that of the structure to avoid resonance. The natural frequency in the cases where the fluid–structure interaction (FSI) is considerably different if considering the coupling added mass (AM) of the water. In this study, vibration experiments were performed using a real propeller in air and water. The modal parameters, natural frequencies, and mode shapes were determined. Validations were performed using 3D solid and acoustic elements in a direct coupling finite element format. The modal results and AM ratios were in agreement with the experimental results. Convenient application and high efficiency are basic requirements for an engineering application. Therefore, an empirical formula was established for the first-order FSI natural frequency to enable rapid estimation, thereby satisfying this requirement.