AI 中文总结
本研究将能量双相动力学辨识（EDDI）扩展至多自由度系统，提出基于分解的EDDI方法，经两层塔结构实验验证，可有效辨识复杂多模态非线性结构动力学。
AI 中文摘要
系统辨识是振动结构建模与评估的重要环节，但许多非线性系统辨识方法过度依赖数据驱动途径，可能无法保持物理一致性。本研究将能量双相动力学辨识（EDDI）方法扩展至经历非线性振动的多自由度（MDOF）机械结构。原始EDDI框架针对单自由度（SDOF）系统设计，分为两个阶段：第一阶段辨识内部非保守力模型，第二阶段捕捉内部保守力。然而，EDDI假设位移为零时势能为零，对于MDOF系统，该假设要求所有自由度（DOFs）同时达到零位移，而这在多模态响应中发生频率过低，无法直接应用。为克服此局限，本研究提出基于分解的EDDI，将EDDI应用于分解后的响应分量，以实现MDOF系统的非线性系统辨识。采用小波有界经验模态分解从实测位移中提取近正交、单色的本征模态函数（IMFs），每个IMF被视为独立的SDOF振子，使用EDDI处理以估计其非保守与保守内力。随后将各IMF的力求和，重构作用于每个物理DOF的总非保守力与保守力，分别用于辨识阻尼与刚度模型。所提EDDI框架在具有两层间强刚度非线性耦合的两层塔结构上进行实验验证，结果表明EDDI在分离与辨识复杂多模态非线性结构动力学方面的有效性。
英文摘要
System identification is an important step in modeling and evaluating vibrating structures, but many nonlinear system identification methods rely heavily on data-driven approaches that may not preserve physical consistency. This research extends the Energy-based Dual-phase Dynamics Identification (EDDI) method to multiple-degree-of-freedom (MDOF) mechanical structures undergoing nonlinear vibrations. The original EDDI framework was designed for single-degree-of-freedom (SDOF) systems and operates in two phases: the first identifies a model for internal nonconservative force, and the second captures internal conservative force. However, EDDI assumes that the potential energy is zero whenever the displacement is zero. For MDOF systems, this assumption requires all degrees of freedom (DOFs) to achieve zero displacement simultaneously, which simply occurs too infrequently in multimodal responses for direct application. To overcome this limitation, this work introduces Decomposition-based EDDI, which applies EDDI to decomposed response components to enable nonlinear system identification of MDOF systems. Wavelet-Bounded Empirical Mode Decomposition is used to extract nearly orthogonal, monochromatic intrinsic mode functions (IMFs) from the measured displacements. Each IMF is then treated as an individual SDOF oscillator and processed using EDDI to estimate its nonconservative and conservative internal forces. The IMF forces are then summed to reconstruct the total nonconservative and conservative forces acting on each physical DOF, which are used to identify the damping and stiffness models, respectively. The proposed EDDI framework is experimentally validated on a two-story tower structure with strong stiffness nonlinearity coupling the two floors. The results demonstrate the efficacy of EDDI in isolating and identifying complex, multi-modal nonlinear structural dynamics.
