海洋平台相似模型设计及模态实验分析

通过理论分析，研究了材料阻尼对相似模型设计及实验数据分析的影响，在此基础上，设计并建造了海洋平台相似模型，并通过多输入单输出的方法对相似模型进行模态实验，得到其固有频率、空间振型、阻尼比等动力学参数。结果表明，材料阻尼对相似模型的几何尺寸没有影响，对模型的固有频率影响不大，可以忽略；但对模型的动力响应影响很大，在实验数据分析中必须加以考虑；为了方便应用，还给出已知阻尼比和阻尼系数时的转换关系。将模态实验数据与仿真分析结果进行对比，二者符合较好，从而验证了相似模型设计与建造的一致性及实验数据的可靠性。

Similar Model Design and Modal Experimental Analysis of Offshore Platforms

The influence of material damping to the similar model design and experimental analysis were studied by theoretical analysis. A similar model of an offshore platform was designed and constructed on the basis of the analysis. The modal experiments were carried out by the model with the method of multi-point excitation and single-point output measurement. The dynamic parameters of the modal were identified including natural frequencies, modal shapes and damping ratios. The results showed that material damping does not affect the geometry of similar model and have a little effect on the natural frequency which can be ignored. But the influence of mode＇s dynamic response is so great that material damping must be taken into account in the analysis of experimental data. In order to facilitate application, the transformation relations of damping ratio and the damping factor which are known were given. The results were proved to he correct compared the data of the experiments with those of the simulation, the consistency of design and construction for the similar model and reliability of the experimental data were to be verified.