全船振动分析等效建模方法

Equivalent Modeling Method for Global Vibration Analysis of Ships

针对全船振动分析中遇到的计算精度和计算成本之间的矛盾,提出等效建模法,即将全船分为等效简化模型、非简化部分和过渡部分进行建模。阐述等效建模法的原理并使用该方法建立某30万吨FPSO全船有限元等效模型,通过分析得到该船主要振动模态的固有频率并与激励源输出载荷频率进行比较。最终得到结论,等效建模法可用于全船振动分析且具有降低计算成本的优点,同时该30万吨FPSO全船的主要振动模态在推进器激励源作用下不存在共振风险且振动响应符合要求。

An equivalent modeling method to solve the contradiction between accuracy and cost of ship global vibration analysis is put forward.Firstly,the whole model of the ship is divided into 3 parts,namely equivalent simplification part,routine part and transition part.Then,the theory of the equivalent modeling method is introduced and the equivalent model of a 300000 DWT FPSO is established by means of the finite element method.Through the analysis,the natural frequency of the main vibration mode of the ship is obtained and compared with the output loading frequency of the excitation source.It is concluded that the equivalent modeling method can be used for the global vibration analysis with lower cost,the main vibration mode of the whole ship excited by the thruster will not cause resonance and the vibration response level is below the standard of the vibration level of 300,000 DWT FPSO.