复杂非线性机械系统的逆向子结构分析方法研究

Accurate dynamic characteristics of components and parameters of the coupling links are necessary for constructing the structural dynamic model of a complex mechanical system, and it is the key to accurate prediction and evaluation of dynamics performance. In practice, it needs disassembling the system to obtain component’s dynamics. However, the disassembling is usually time-consuming and the boundary conditions are not correct anymore. Besides, in some cases substructures cannot be measured separately but only when coupled to neighboring substructures. Therefore in order to quickly and accurately obtain the dynamics information of components and the corresponding links, the identification of substructure dynamics based on in-situ measurements has become a hot spot of the research. In this study, the inverse substructuring method for nonlinear mechanical systems will be studied based on structural dynamics theory, matrix theory and nonlinear system analysis methods. The nonlinear structural dynamic decoupling of rigid links will be investigated to reveal effects of nonlinear characteristic parameters of rigid links on the relationship between the frequency response function (FRF) of components and that of the system. By studying the coupling effect between link nonlinearity and FRF of components, the inverse substructuring method considering the link nonlinearity will be proposed and then validated by practical engineering cases. By doing so, it is hopeful to provide a reasonable and effective method for quick and accurate prediction and evaluation of dynamic performance of complex nonlinear mechanical systems, improving effectively ability of the dynamics analysis. The result will provide theoretical guidance and technical support for the development of techniques related to vibration analysis and control.

复杂机械系统部件及其结合面的准确动力学信息是建立高精度动力学模型，实现动力学性能精确预测和评估的关键。在实际系统物理拆分过程中存在测量困难、耗时过长及约束边界改变等问题，为了快速准确获得部件及其结合面的动力学信息，基于系统原位测试数据的子结构动力学特性辨识研究成为国内外关注的前沿课题。本项目将基于结构动力学理论、矩阵理论和非线性系统分析方法，研究刚性连接件结合面的非线性动力学解耦机制，探明连接面非线性特征参数对部件级与系统级频响特性之间关系的影响规律，并揭示非线性特性与部件级频响特性之间的耦合效应，提出考虑连接面非线性特性的逆向子结构分析方法，通过实际工程案例验证方法的有效性和合理性。研究成果能够为复杂非线性机械系统动力学性能的精确预测与评估提供合理科学的方法，提高其动力学分析能力，并为振动分析与控制相关技术的开发提供理论指导和技术支持。

复杂机械系统部件及其结合面的动力学信息是影响动力学模型精度的重要因素，如何基于系统原位测试数据，快速、准确获得部件及其结合面的动力学信息，建立高精度结构动力学模型，对于复杂机械系统动力学性能的精确预测和快速评估有着重要意义。本项目旨在通过研究刚性连接件结合面的非线性动力学解耦机制，量化非线性特性与部件级频响特性之间的耦合效应，提出非线性机械系统的逆向子结构分析方法。项目建立了弹性连接、刚性连接状态下的子结构动力学特性与系统级动力学特性数学关系方程，推导出子结构动力学特性关于系统级动力学特性的显式表达式，形成刚性连接系统的逆向子结构分析方法，对子结构动力学特性原位识别效果进行了分析及验证；发展了组合结构动力学修改下的系统动力学响应预测方法；基于以上研究成果，提出了基于传递率矩阵概念的非线性子系统原位识别方法。项目建立了完整的分析理论、算法流程和实施案例，为复杂非线性机械系统动力学性能的精确预测与评估提供合理科学的方法，并为其动力学分析能力的提高提供了理论支持和技术基础。