中文摘要：

随机子空间法是近些年来发展起来的一种线性系统识别方法，可以有效地从环境激励的结构反应中获取模态参数。属于时域的方法，这种时域识别方法基于状态空间模型，仅利用结构输出反应，避免了传统的人工识别和迭代过程。它不仅可以识别结构的频率，而且可以识别结构的阻尼和振型。介绍了随机子空间的理论，用该方法对一框架模型进行参数识别，通过与有限元识别结果的比较证明了随机子空间方法不失为一种有效的模态参数识别方法。

英文摘要：

Stochastic subspace method is a novel approach developed in recent years. It can identify the structural modal parameters by ambient vibration. Stochastic subspace identification is a time domain method, and can identify the frequency and damping ratio, with the response data of ambient vibration, this time domain identification method can extract structural modal parameters based on the state space model, avoiding conventional manual identification and iterative process. The main theory of this approach is introduced at first. Using ANSYS program＇s result to prove the modal parameters of the frame model is identified by stochastic subspace identification.