自由-自由结构模态参数提取方法研究

从约束试验数据提取自由-自由结构模态参数是试验模态分析领域中的一个重要课题。从多自由度系统特征方程出发，阐述了适合于不同约束条件（弹性和刚性）的两类自由-自由结构模态参数提取方法的基本理论，旨在比较它们的可行性及适用范围。以-悬臂梁结构为基本算例对两种算法进行了深入的数值模拟研究，对模拟结果进行了比较分析。结果表明，两类方法在不同的约束条件下各有优点，存在各自的适用范围，是获取大型航空航天结构整体动态特性的有效途径。

Study on Extraction Methods of Free-Free Structural Modal Parameters

Extraction methods of free-free structural modal parameters from constrained test data play a key role in the experimental modal analysis field. Based on the system equation with many degrees of freedom, two kinds of extraction methods are reviewed and presented in this paper. They are suitable for different constraint conditions including elastic constraint and rigid constraint respectively. A numerical simulation is deeply conducted on a cantilever beam and the simulation results are compared and analyzed. The feasibility, strengths and application scope of each algorithm are discussed. The results show that the two methods have respective merits and application scope under different constraint conditions. They are all feasible to obtain the whole dynamic characteristics of the large-scale aerospace structures and the identification precisions axe all satisfactory.