循环对称结构重根模态振型相关性修正

为消除循环对称结构有限元模态分析和试验模态分析对应重根模态振型之间的夹角误差，实现模态相关性的准确定量分析，基于模态振型方程，揭示不同模态模型重根模态振型夹角误差产生机理，提出修正循环对称结构模态振型相关性的新方法。计算各阶重根模态有限元模态振型与试验模态振型间互模态置信准则(Cross modal assurance criterion, Cross MAC)初值得到夹角误差；在此基础上确定出对应的旋转角度和测点数；对有限元模态振型进行旋转匹配并计算得到修正后的Cross MAC值。应用该方法对制动盘有限元模态模型和试验模态模型进行相关性修正，结果表明：该方法不仅能获得准确的循环对称结构模态相关性，且相比于已有的循回群和初等旋转变换方法而言，修正效率得到显著提高。

Correlation Correction for Doublet Mode Shapes of Cyclic Symmetric Structures

In order to eliminate the angle errors of doublet mode shapes which are obtained by finite element modal analysis and experimental modal analysis for cyclic symmetric structures and then realize accurately quantitative modal correlation analysis, the formation mechanism of angle error between mode shapes of doublet modes from different modal model is revealed and a new mode shape correlation correction method of cyclic symmetric structures is presented based on mode shape equations. The initial Cross modal assurance criterion (Cross MAC) value of each doublet modes between finite element mode shapes and experimental mode shapes is calculated. Angle errors and the corresponding point number which should be rotated are worked out. The corrected Cross MAC value and accurate analysis results of modal correlation for cyclic symmetric structures are achieved after matching the finite element mode shapes again. Taking brake disc as an example, the new method is applied to correct correlation between finite element modal model and experimental modal model. The results show that not only the correlation can be achieved accurately, but also the correction efficiency compared to existing cyclic group and elementary rotation transformation methods is increased.