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Strand 7 Error: Global stiffness matrix is singular

Strand 7 Error: Global stiffness matrix is singular

Strand 7 Error: Global stiffness matrix is singular

(OP)
Hi,

Does anyone know how to solve the problem of "Global stiffness matrix is singular"? I have a shell structure built in Rhinoceros and imported into Strand 7. After conducting surface automeshing, I have applied the plate thickness as 400mm and defined the fixed supports. However, when I run the model, the error message popped up sand saying " Global stiffness matrix is singular". I don't know why this happened, can someone have a look at my files and tell me where did I go wrong?

Thanks,
Ryan

RE: Strand 7 Error: Global stiffness matrix is singular

Edited after looking at the log file.

OK, so you have got plates, nodes etc.

Have you defined material properties and node restraints?

Can you upload your ST7 file.

Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/

RE: Strand 7 Error: Global stiffness matrix is singular

(OP)
Hi Doug,

Thanks for replying my post. Yes, I have defined material properties and node restraints. Basically, I have defined the fixed bottom supports and a hinge support at one side of the shell, and left all other nodes unchanged. The link to my ST7 is attached to my original post, could you please have a look at it? My running result is attached to this reply. Really appreciated.

Kind Regards,
Ryan

RE: Strand 7 Error: Global stiffness matrix is singular

Ryan - both links are to the log file (.lsl). I need the .st7 file.

Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/

RE: Strand 7 Error: Global stiffness matrix is singular

(OP)
Hi Doug,

I have attached the .st7 file, but have no idea why the link is connected to the .lsl file. Here is the Google Drive link for the .st7 file(https://drive.google.com/file/d/1_0ah_ajULjpjFJeNk...). Could you please have a look at the .st7 file?

Thanks,
Ryan

RE: Strand 7 Error: Global stiffness matrix is singular

The model has 1118 different plate properties, and only the first one has non-zero values. If you assign property type 1 to all the plates the analysis completes successfully.

Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/

RE: Strand 7 Error: Global stiffness matrix is singular

(OP)
Hi Goug,

Thank you so much! The problem has been solved now.dazed

Kind Regards,
Ryan

RE: Strand 7 Error: Global stiffness matrix is singular

(OP)
Yes, it's one of the shell roofs of Sydney Opera House.

RE: Strand 7 Error: Global stiffness matrix is singular

Hi Ryanhhh97

Have a look at the online content on the Strand7 website, there is a lot of information with regards to debugging models.

It may help in the future.

RE: Strand 7 Error: Global stiffness matrix is singular

(OP)
Hi Mohanlal0488,

Yes, I did. Thank you so much for your advice.

Ryan

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