engleski

Analitički i numerički proračun dodatne mase kod analize vibracije broda

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.

added mass; boundary element method; finite element method; ship vibrations

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