船舶总振动固有频率实用算法

分别用一维梁有限元方法和三维有限元方法计算3艘实船总振动固有频率,对计算结果进行统计分析,提出对一维梁有限元方法计算结果的修正,利用110000t油船进行验证。用一维梁有限元方法计算时考虑剪切滞后影响系数;用三维有限元方法计算时, 是在ANSYS软件中建立全船的三维空间有限元模型,进行模态分析。通过计算证明该方法能有效改进一维梁有限元计算方法,可快速准确地预报船舶总振动固有频率。

Improved Algorithm for the Natural Frequencies of Ship Vibration

One-dimensional beam FEM method was previously used to predict the ship vibration level, but the precision droped greatly upwards four nodes, for the hull shear deformation was greatly effected at high orders. The results of 3D space FEM model calculation were proved more accurate, but it consumed too much work. It was valuable to improve one-dimensional beam method. Hull vibration frequencies of 3 ships were calculated with both one-dimensional beam FEM method and 3D FEM methods. The results were compared and improvement to one-dimensional beam FEM method was provided. 110 000 t oil tanker was used to prove that improvement. The shear lag coefficient was used in one-dimensional FEM method; 3D space FEM model of the whole ship was established in ANSYS software. It was proved that the modified one-dimensional FEM method was valid for 110 000 t oil tanker. It was valuable to predict hull frequency quickly and more accurately.