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Saving and Retrieving Normal Modes Analysis Results

Hello Everyone!

I am doing a response spectrum analysis an like to retrieve a eigenvalues and vectors from normal modes analysis which has already done. I hav saved the eigen value using EIGVNAME = modes and EIGVSAVE = 100. The file is has saved as modes.100.eigv.

While doing RSPEC, I retreived the eigv using EIGVRETRIEVE = 100 and same EIGVNAME. But Solving throws an error as,

*** ERROR # 372 ***
Number of MPC constraints in file modes.100.eigv 474
does not match current value 0.

Can Someone figure it out .

Thanks in Advance

-RathinaVel

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Altair Forum User

Hi Subhu,

Make sure you have requested enough modes to save in EIGRL card.

Subhu_21017

To add a point, I have created 79 pretension bar elements.

In modal Anlaysis, I have found the preloaded/ pre stressed modes.

This 79*6 = 474, is doing something, that I am un able to figure out.

Rahul Rajan_21763

FYR i have attached fem file. Analysis of a Preloaded Bridge Model with Pretension.

Unable to find an attachment - read this blog

Subhu_21017

Hi Rahul,

Thanks. But I have no problem in solving modal analysis with preload.

I have to do a response spectrum analysis, for which I have to use the preloaded modes.

I have saved the eigv file on the modal analysis. On retrieving the file using Eigen retreive in RSPEC analysis throws an error as I mentioned above.