Analytical and Numerical Computation of Added Mass in Ship Vibration Analysis
نویسندگان
چکیده
Original scientific paper Comparison between analytical and numerical determination of the added hydrodynamic mass in ship vibration analysis is performed. Analytical analysis was done on a semi-submerged cylinder of a circular cross section. Numerical calculations were carried out by the boundary element method (BEM) implemented in NX Nastran finite element (FE) software. Fairly good agreement was found between the two methods for added mass calculation. Also, analysis of the real ship vibrations is performed. Free vertical vibrations of a 9200TEU containership are analyzed where the hull was modelled by the beam finite elements (FE), while the shell plating was modelled by the plate FE without stiffness to define boundary elements of the wetted surface. Such calculated results are compared with the ones obtained by software DYANA which uses Timoshenko's beam FE and in which the added mass is determined by traditional analytically-based method. Comparative analysis shows some moderate differences in the calculation of added mass between the two approaches, indicating the need for further research on this topic.
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Model identification and dynamic analysis of ship propulsion shaft lines
Dynamic response analysis of mechanical structures is usually performed by adopting numerical/analytical models. Finite element (FE) modeling as a numerical approach plays an important role in dynamic response analysis of complex structures. The calculated dynamic responses from FE analysis are only reliable if accurate FE models are used. There are many elements in real mechanical structures w...
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