the different results between 2D and 3D problem

[burnningcat]

Dear Sir,
I find that the analysis results of the 3D problem is a little different from the 2D problem, also the 3D problem is much difficulty to converge compare to the 2D problem, for the same model.

For example, you can perform a push-over analysis of a cantilever column with the “beamwithhinges” element, and you can find the results are around 5% to 10% different between 2D and 3D problem. But because there should not be the torsional effect, so this is strange.

Another problem is the same frame can converge in 2D , but it can not converge in 3D. Even I fix the DOF in the out-of-plane, and I don’t consider the torsional effect, it just can not converge.Also I kindly ask if somebody can tell me the different between:

1. with or without rigidDiaphgram, wichi one can converge better?

2. “Constrain Transformation” or “constrain Penalty”, wichi one can converge better?

3. to divide the fiber section to 5X5, 10X10 or 15X15, whichi one can converge better?

4. “BeamWithHinges element” or “NonlinearBeamColumn element”, wichi one can converge better?


The convergence problem almost drive me mad. Even I use the very good loop it just quite difficult to converge.So I kindly ask if somebody can tell me some information? Many thanks for you.