基于实测分析的科考船振动数值模型修正

Correction of Numerical Model for Vibration Based on Actual Measurement Analysis of a Scientific Research Ship

以对振动控制要求较高的科考船为例,采用实测和有限元分析方法开展船舶振动特性精确预报研究。对正常航行状态下的实船振动响应进行测试分析;建立科考船三维有限元模型,对主机与螺旋桨激振力共同作用下的船体时域瞬态响应进行计算,并参考规范和指南中的激励力计算方法施加船体激励;利用实测数据对结构阻尼、附连水质量和约束设置等有限元参数进行修正,获得船体各测点的振动响应结果。研究表明:修正后的数值模拟结果与实测振动响应能较好地拟合;利用修正后的有限元模型能更精确地预报船舶结构在任意位置及不同工况下的振动响应。

A scientific research ship with high requirements for vibration control is taken as the example to study the precise prediction of ship vibration characteristics based on the measurements and the finite element analysis.The vibration response of the ship under normal navigation conditions are analyzed,and a three-dimensional finite element model of the ship is established to calculate the time-domain transient response of the ship under the combined excitation force of the main engine and the propeller,of which the excitation forces to the ship are applied according to the calculation method in the specifications and guidelines.Measured data are used to modify finite element parameters such as structural damping,attached water mass,and constraint settings,to obtain the vibration response results of each measurement point on the hull.The results indicate that the modified numerical simulation can well fit the measured vibration response and the modified finite element model can predict more accurately the vibration response of ship structures at any position and under different working conditions.