基于NExT/ERA方法环境激励下的船体结构模型总体模态参数识别

Identification of modal parameters for model of a ship hull girder under ambient excitation based on NExT/ERA method

运行模态识别是一种仅仅根据环境激励下的结构振动响应来提取结构模态参数的方法,此方法一般基于环境激励为白噪声的假设。文章讨论了NExT/ERA方法在船体结构总体模态识别中的可行性,并采用了自然激励技术与特征系统实现算法相结合的方法,识别了船体模型的总体模态参数。文中还讨论了NExT/ERA方法的基本理论及计算流程,并引入了奇异值分解图和稳定图相结合的方法更好地确定系统的阶次;最后,用NExT/ERA算法有效地识别了简支梁模型和船体模型的模态参数。

Operational modal analysis methods are procedures that abstract modal parameters of structures only from response, these procedures are always based on the assumption that the excitations are white noise. In this paper, the feasibility of NExT/ERA in identifying modal parameters ~f ship structures is discussed, and the modal parameters of a general ship model are identified using NExT/ERA. The basic theory of NExT and ERA are discussed; a method of identifying system order that combines the singular values decom- position and stabilization diagram is introduced to identify system order better; Finally, with NExT and ERA method, the modal parameters of a simply supported beam and a ship model are identified efficiently.