Solution matrix is not factorizable

HI
iam getting this error after using mumps solver, and I am not sure why I am receiving this error

I shared my project if you like to have a look
https://www.simscale.com/workbench/?pid=9019955115809875354&mi=run%3A36%2Csimulation%3A34&mt=SIMULATION_RUN

Hi khalidElserfy1,

thanks for reaching out to us here in the forum. Can you please provide us with a short description of your project, with an overview of what you want to achieve? So that we can verify your simulation setup. :slight_smile:
Maybe a quick simplified drawing with the boundary conditions and applied forces?

Best regards
Sebastian

thanks for your reply


so this is like an umbrella design and i and willing to test the effect of lift and drag force which is applied as a remote force on the ends of the ribs, and the umbrella is fixed from the bottom, and I am doing the analysis on on half of the model

@SBlock i have added a description for the case, Iam trying to solve
pls let me know if it is not clear

thx

Hello Khalid, sorry for the late reply. Here are my findings while working on your project.

-To resolve the “Matrix is not factorizable” issue, please change the Symmetry boundary condition to a Fixed Value boundary condition for symmetry faces. Only displacement in X direction should be constrained with 0 meters to satisfy symmetry behaviour. Others should be left as unconstrained. Symmetry boundary condition may cause issues when it’s faces share common edges with some other boundary faces such as Fixed Support. This is something being worked on at the moment on development side.

-Looking at your meshing log, overall quality and some individual mesh quality parameters seems not good. In order to achieve a better mesh quality, please define a Small Feature Suppression value of 0.0001 under advanced mesh settings. This setting will allow mesher to ignore faces with dimensions smaller than 0.0001, in return providing a better mesh quality.

-Since the geometry in your application is fairly complex, it will not be possible to increase the mesh quality further than a certain value. That’s why it’s likely that you’ll receive "The desired residual of the MUMPS solver could not be achieved. " warning. Here I have two suggestions:
1. Simplify your geometry in your own CAD software. You can get rid of unnecessary details in your geometry which you think will not affect your simulation results.
2. Reduce the linear system relative residual under Numerics in the simulation tree. In my testings after increasing the small feature suppression value, I was able to obtain an error around 0.00075. However, please be aware that this method might decrease the accuracy of your simulation.

Hope these are helpful.

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