error in eigen value analysis

03-Analytical/modelling capabilities
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Ahil_Anand
Posts: 32
Joined: 11 May 2017, 04:49

error in eigen value analysis

Post by Ahil_Anand »

The program give me this message when I'm trying to run a simple RC beam:
Node 1 and Node 2 of the LINK_r link element should initially coincide
What is the problem? These two nodes have the same cordinates!! I remove the link and create it again, but the message still apeare. Dear Seismosoft, I had this problem in several models. In all of them, the first analysis was for example pushover, but, when I change the analysis type to Eigen value analysis type, thiss message was appeare and the seismostruct didn't run eigen value analysis, while, there was no problem and message in its previous analysis.
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seismosoft
Posts: 1184
Joined: 06 Jul 2007, 04:55

Re: error in eigen value analysis

Post by seismosoft »

Hello Ahil,
How did you create the model?. Have you used MS Excel to create the nodal coordinates? If this is the case, note that sometimes the numbers created with Excel are not rounded, but this is not shown in SeismoStruct (i.e. you can have a coordinate X=1.0000000000045 which is shown as 1.000 in SeismoStruct). Can this be the problem? Have you tried to delete the nodes and create them again?
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Ahil_Anand
Posts: 32
Joined: 11 May 2017, 04:49

Re: error in eigen value analysis

Post by Ahil_Anand »

No, I didn't use Excel.
As I said, I have been deleted the nodes and create them again. But the error was remained. These nodes are the origin point 0,0,0.
I had this problem only when I change the analysis type. The first type of analysis was done without any problem, but with changing the type of analysis, the error message was appear. I had this problem in several models specialy when the second type of analysis is Eigen value analysis.
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seismosoft
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Joined: 06 Jul 2007, 04:55

Re: error in eigen value analysis

Post by seismosoft »

This is very strange indeed. The only occasion, when such behaviour was reported by our used was when a user employed Excel to automatically calculate the coordinates of the nodes. Further it makes no sense at all that the link element are defined correctly in one analysis type and not in another.
Can you please send the spf file of one of the models with problems to: support@seismosoft.com?

Regards,
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Ahil_Anand
Posts: 32
Joined: 11 May 2017, 04:49

Re: error in eigen value analysis

Post by Ahil_Anand »

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seismosoft
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Joined: 06 Jul 2007, 04:55

Re: error in eigen value analysis

Post by seismosoft »

We were able to run the analysis several times without problems. See:
http://seismosoft.com/Public/screenshot.png

Please make sure that you are using the latest SeismoStruct release (downloaded from our website),registered with an official license.

Regards,
Seismosoft Support
Ahil_Anand
Posts: 32
Joined: 11 May 2017, 04:49

Re: error in eigen value analysis

Post by Ahil_Anand »

Dear Seismosoft,
I know that the file has not any problem with runing the current analysis type (push over). I also use the latest version.
The error messege appear when I change the analysis type to Eigen value analysis. As I said before, I had this problem not only in this problem, but also in many different models. Please sure that it is not about a bug. Regards
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seismosoft
Posts: 1184
Joined: 06 Jul 2007, 04:55

Re: error in eigen value analysis

Post by seismosoft »

Hello Ahil,
Indeed, the eigenvalue file gives a bug, which strictly speaking is not a bug of Seismosoft, but rather of the compiler (it gives 1-1=1e-10, instead of zero).
Thank you for spotting that, we will have it fixed in SeismoStruct 2018.
In the mean, you can fix your model if you change the Z - coordinates of all the nodes to 0.00, rather than 1.00.

Seismosoft Support
Ralazem
Posts: 63
Joined: 08 Feb 2019, 02:38

Re: error in eigen value analysis

Post by Ralazem »

Has this been determined to be a bug? I am having the same issue, and my nodes are coincidental. Only when trying to do an eigenvalue analysis does this occur.
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seismosoft
Posts: 1184
Joined: 06 Jul 2007, 04:55

Re: error in eigen value analysis

Post by seismosoft »

It is an old bug from some years ago. In theory it should be fixed. If this is not the case, can you please send the file to support@seismosoft.com?
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