04patran nastran教程513g加密所属kafeimao msc官方.pptx
- gcq的书屋个人认证 |
- 2021-11-29 发布|
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;TABLE OF CONTENTS;We have seen that the Eigenvectors that we calculate in a Normal Modes Analysis are independent of each other and are arbitrarily scaled.
Until we apply some kind of loading – either transient or frequency response, then it is very difficult to predict which modes will play a dominant part in a structure.
One way we can help predict what are the important modes is to use a technique called Modal Participation Factor.
We know that linear combinations of Eigenvectors can be assembled to make arbitrary shapes. In this case we say that the shape to be made is a Rigid Body Vector in the direction of response we are interested in.
The Rigid Body Vector is DR
And we assume where e is a vector of scaling factors on the eigenvectors F, i.e. a set of Participation Factors.;Pre Mul