Nastran setup or 3d model preparation for faster results

brane_stankovic — Fri, 10 Apr 2026 10:46:25 GMT

Hello to all,

I need help to try to understand what would be the best method for calculating stress and deflection for steel mould for pre-cast concrete segments for bridges.
In the photos attached is the 3D model for which we need to understand. Only one half of the mould is shown.

Which approach would be the best in case like this?

Many thanks in advance.

Re: Nastran setup or 3d model preparation for faster results

John_Holtz — Fri, 17 Apr 2026 17:49:05 GMT

Hi @brane_stankovic

I think the easiest is to analyze it using solid elements. I would mesh it with Linear element order and run the analysis until you get all the bugs worked out in the model setup. Then switch the mesh to Parabolic element order to do the final run to get more accurate results.

Shell elements might be preferred for the beam structure, but I think it will take you more time to create the shell elements and get everything working do to the complexity of plate-on-top-of-plate and the amount of details. Although the solid elements will take longer to run, that time is computer time versus your personal time if you try to make things using shells.

The beam structure is a little too "chunky" to make beam elements useful. If the structure was longer and more slender, then beam elements might be useful for some of the structure.

John

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Nastran setup or 3d model preparation for faster results

Re: Nastran setup or 3d model preparation for faster results