In analysis of ship global vibration, influence of outboard water should be considered. For studying the global vibration, two methods can be used. One is that 3D finite element model of water domain is applied, and the other is that added mass is introduced into structural matrix for calculation. With the finite element technique developing, 3D finite element model of ship is usually taken. However, it is not correct for traditional method (such as Lewis added mass method) to neglect the deformation of ship transverse section. We proposed a kind of boundary element method to calculate the 3D added mass matrix of structure with 3D effect, and analyzed the wet structural response. The results show that the method is available and accuracy.%船舶总体振动分析需考虑对船体外部水的影响.通过建立水域三维有限元模型进行计算或者先计算出附加质量后,加入到结构质量中进行计算.随着有限元技术的发展,船舶大都采用三维有限元建模.传统方法,例如刘易斯附加水质量法,虽然考虑到纵向变形,但确没有忽略船体横剖面的变形,因而不够准确.采用三维边界元方法,考虑水中结构振动的三维效应,计算三维附加质量矩阵,并对水中结构振动进行分析.结果表明,水中结构振动是三维变形,应该采用三维附加质量矩阵进行振动分析.
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