确定AR模型解中真实模态的稳定图法  

Stabilization diagram method to determine the real modes in AR model

作　　者：何俊[1] 陈怀海[1] 贺旭东[1] 

机构地区：[1]南京航空航天大学航空宇航学院,南京210016

出　　处：《国外电子测量技术》2012年第5期36-40,共5页Foreign Electronic Measurement Technology

摘　　要：提出了利用模态稳定性图来确定AR模型解中真实模态的方法,从而避开了传统方法中的定阶难点问题。首先建立了一个悬臂梁的有限元模型,得到了其振动时域响应,建立了用于振动模态识别的AR模型。其次令AR模型的阶次在一定范围内逐渐增大并进行相应求解计算,得到模态频率的一系列值并作出稳定图。在图中出现的数条稳定竖线所对应的频率值为系统的真实模态频率。通过短时平稳假设,可将其推广应用在时变系统模态频率识别中。A stabilization diagram method is presented to determine the real modes in AR（auto-regressive） model to avoid the difficulty of order determination in traditional methods. Firstly,a finite element model of a cantilever beam is established and the time-domain vibration response is calculated,then an AR model for modal parameters identification is set up. Secondly,let the order of AR model vary in a certain range and a series of modal frequencies is obtained,so as to draw the stabilization diagram. Some vertical lines appearing in the diagram correspond to the real modes. It can also be applied in modal parameters identification of time-varying system by short-term stationary assumption.

关 键 词：AR模型 模态频率 稳定图 时变系统 

分 类 号：O328[理学—一般力学与力学基础]