need help with solver pivot warning or error

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  • Last Post 18 February 2020
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garym posted this 18 February 2020

here I have attached a bridge structure with I beams. I keep getting the "solver pivot error", I have tried adding a modal into workbench and trying to see which beam components/ deformations were giving me the error. Also, I have tried under solution (A6) and analysis shutting off the solver pivot checking. Which I think helped a little bit because allowed me to solve but I see where the problem is to the left portion of the beam I don't think the beams are connected. How do I go back and fix this connection or ultimately this error pivot message to get the solution of total deformation I am looking for? 

 Thanks!

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Aniket posted this 18 February 2020

Ansys staff can not access the attachment on the community. Kindly post them as inline attachments. Also, Modal analysis would solve in most cases without any issues, but you have to interpret the results and eliminate zero-frequency aka rigid body modes. This can be done by using proper contacts, and or use of constraints in the model.

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garym posted this 18 February 2020

Hello I have updated and reattached the attachment as separate pictures. Please let me know if you have access to them now in my previous post.  In Modal Analysis you are correct it did solve it but I didn't know how to interpret the results. So I when into the Analysis under solution (A6) and turned off the checking for solving pivot error off  then hit solve it solved and gave me an answer but I don't think it is the correct one since the one side of my bridge is not connected properly. Is there anyway I could go back and fix the beams in the geometry then update the mesh etc. and solve? Also how do you know your drawing lines correctly and there connected  in geometry for future reference so this doesn't happen again.

Thanks!

 

Aniket posted this 18 February 2020

right-click on the model branch of the tree insert mesh edit. After inserting the mesh edit, right-click on it and insert Node merge group. provide suitable tolerance to merge the nodes and rerun the modal analysis. Check if you have any zero or near-zero frequencies. check total deformation for those frequencies and manually merge the nodes if required.

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garym posted this 18 February 2020

Thank you!

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