Seismosoft | Earthquake Engineering Solutions

I experienced numerical instability when using a very fine element mesh, while with a coarser mesh numerical instability improved and delivered satisfactory pushover results. I investigated the results of the coarser mesh and found that the results were accurate.

What could be the reason for the improved numerical stability with a coarser mesh?

Your observations are correct (in fact, in the Help System, it is mentioned how very fine meshes can lead to numerical instabilities).

You may find other discussions in this Forum on the same issue (do a search on "localisation"). You may refer also to the existing literature on such topic: numerical localisation in nonlinear analysis.

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