A Study on Expansion of Mode Shapes and Residual Stiffness for Structural Dynamics Modification

结构动力学修正的振型扩展和残余刚度研究

基本信息

批准号：
15560198
负责人：
KURATANI Fumiyasu
金额：
$ 1.34万
依托单位：
Wakayama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15560198/
关键词：
Modal Analysis Finite Element Method Structural Dynamics Modification Mode Shape Expansion Plate Structure Rib Stiffener Condition Number Boundary Condition 振動モード剰余剛性実験モード解析

项目摘要

For the experimental modal data based structural dynamics modification(SDM) method, mismatch in degrees of freedom between the model of the modified part and the measurement data, and also modal truncation are serious problems. In this study, the estimation methods for mode shapes and residual stiffness at the unmeasured points has been proposed and incorporated into the SDM procedure to settle the problems.First, the estimation method for mode shapes at the unmeasured points has been developed using the mode shape expansion method and its accuracy was examined. The mode shapes at the unmeasured points are estimated with sufficient accuracy from the submodel with a free-free boundary condition. In addition, when the number of measurement points is insufficient, the accuracy of estimates decreases with increasing the number of modes combined. The proper number of modes to be combined can be determined by checking the rapid increase in the condition number of the modal matrix of the submodel.Next, the estimation method for residual stiffness at the unmeasured points has been developed as an extension of the mode shape expansion method and its accuracy was examined. The developed method estimates the residual stiffness, though the accuracy of estimates of residual stiffness is lower than that of mode shapes.Finally, the SDM procedure with the mode shape expansion method has been developed and the accuracy of predictions was examined. The modification of a thin plate structure with the L-shaped ribs was introduced as a practical example. The developed procedure produces the accurate predictions of the natural frequencies of the modified structure by the use of the estimated mode shapes at the unmeasured points even when the ribs are attached to the locations where mode shapes are not measured.

对于基于实验模态数据的结构动力学修改（SDM）方法，修改部分模型与测量数据的模型之间的自由度不匹配，而模态截断也是严重的问题。在这项研究中，已经提出了模式形状的估计方法和在未衡量点处的残留刚度，并将其纳入了SDM程序以解决问题。首先，使用模式形状扩展方法开发了未衡量点的模式形状的估计方法及其精度。估计未衡量点的模式形状，并以免费的无边界条件从子模型中估算出足够的精度。另外，当测量点的数量不足时，估计值的准确性随着模式组合的增加而降低。可以通过检查子模态模态矩阵的状况数量的快速增加来确定要组合的正确数量。Next，已开发出剩余刚度的估计方法是作为模式形状扩展方法的扩展及其精度的扩展。开发的方法估计了残留刚度，尽管残留刚度的估计值低于模式形状的估计值。在本文中，已经开发了具有模式形状扩展方法的SDM程序并检查了预测的准确性。用L形肋骨的薄板结构的修饰作为一个实际例子。开发的过程通过在未衡量的点上使用估计的模式形状在未测量的点上使用估计的模式形状，从而产生对修改结构的固有频率的准确预测，即使肋骨连接到未测量模式形状的位置。

项目成果

期刊论文数量（12）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Structural Modification Procedure for Rib Stiffener Location

肋骨加强筋位置的结构修改程序

DOI：
发表时间：
2003
期刊：
Proceedings of 10th Asia-Pacific Vibration Conference Volume 1
影响因子：
0
作者：
F.Kuratani;T.Simada;T.Yamano;T.Ogawa;S.Washio;Fumiyasu Kuratani;Fumiyasu Kuratani
通讯作者：
Fumiyasu Kuratani

Fumiyasu Kuratani: "Structural modification procedure for rib stiffener location"Proceedings of the 10th Asia-Pacific Vibration Conference. Volume 1. 343-348 (2003)

Fumiyasu Kuratani：“肋骨加强筋位置的结构修改程序”第十届亚太振动会议论文集。