I think that the effect of the analysis in three dimensions more realistic to enter all the structural elements in the Structural Analysis and increase accuracy in the solution ,as the solution of folded plates , which depends on the idea of a lack of offsets for contact points of plates which in fact suffering deflection

Three dimensional analysis gives more accurate solutions. In particular when lateral loads are considered like Seismic and wind load analysis, 3D analysis is preferred..

If you analyze in 3D model, then you might have the higher errors in your results because the software can not analyze as careful as possible in comparison to the 2D model, Although if you model your structure as a 2D model and then you do your analysis, as the procedure is simpler for the software, it can give you the better results. Finally you can add all parts of your 2D model together.

Conditions in the three-dimensional case is closer to the truth until we have sufficient mastery over the next two we can not go looking for three-dimensional analysis.

Hi Ahmed

In general, we can't say that two or three dimensional structural analysis lead to different errors or accuracy. Depending on analysis conditions, available parameters for structural analysis, mesh types, used element types for  FE analysis, implemented models for analysis, the type of used FE software and etc, different results may be occure. If all mentioned conditions be same for two or three dimensional structural analysis then we can say that two dimensional analysis may be more accurate than three dimensional otherwise we can not say this. For example, if all needed parameters available for two or three dimensional structural analysis, three dimensional analysis  in MIDAS lead to more accurate results in contrast to two dimensional analysis in Abaqus or Ansys. Whatsoever the used elements, models, mesh types is simpler and number of implemented parameters be low, the resulted data may have higher accuracy so from this point of view we can say that two dimensional analysis may have higher accuracy beside three dimensional analysis. I have an idea for full analysis of a structure, this process can be summarized as follow:

1- Create your desired geometry in 2D.

2- Apply a complete model for your analysis even this model be a model for three dimensional analysis. In this case, you can use from default value for your selected model or use from a complete model in  two dimensional analysis.

3- Perform your analysis in two dimension.

4- Now expand your two dimensional analysis to three dimensional analysis by replacing full three dimensional needed parameters default values by real values in three dimensional analysis. Note that you must change mesh type for this purpose.

You can use from FLAC or MIDAS for structural analysis.

Be success.

3D analysis is more realistic, and more representative since every thing is 3m, but it depends what you need

3D analysis is more complex and time consuming, so main key is to link your goals to your model, whatever is the simplest model that can do the job with high accuracy is the best choice even if it's 1D

what is the benefit of bying Airplane while all my travels are inside the city

best of luck

in folded plate or cylindrical plate

for Design usually 2D is good since we don't care about depth

for research, I think it's good to see what's going on across the thickness of plate

in case that no need for a business inside the thickness ,2D is efficient

Dear Dr Ahmed

There are essential differences in the finite element modeling approach for 2D/3D based on space dimension and 2D/3D element dimension.

The first approach include e.g. 2D/3D frames based on one dimensional beam element

Also shear wall or folded plate could be 2D model based on 2D shell element or 3D solid element

The accuracy depends: material model (uniaxial, plain stress/plane strain, 3d yield criteria)

: Geometry nonlinearity, higher order stiffness, DOF, Coupled responses

; Solver, numerical integration, iteration, force/displacement control 

; Boundary condition modeling rigid or flexible

Assumption of homogenous/ isotropic

All above should be justified and validated through different approach to get satisfied with the outcome results, compromised the target objectives and the required efforts/costs

Die Unterschiede zwischen der 2D oder Bauteilorientierte Berechnung und 3D oder Berechnung auf Basis des Gesamtmodells kommen daher, dass die beiden Berechnungen unterschiedliche Randbedingungen zugrunde liegen. Die einwirkenden lasten, die Auflagerbedingungen, eventuelle Zwängungen und die Steifigkeiten werden unterschätzt.

Bei einer klassischen Massivbauweise (Decke, Wände, Stütze, Balken aus Stahlbeton) reicht in der Regel eine 2D-Berechnung und liegt auf der sichereren Seite, wenn die Bemessung an der ungünstigsten stelle erfolgt.

3D-Berechnungen sind dagegen sinnvoll bei Stabilitätsuntersuchungen wie Gebäudeaussteifung, Erdbeben, Baudynamik und usw…

Bei der ganzheitlichen Berechnung werden alle Bauteile 3-achsig beansprucht, daher zeigen unterschiedliche Schnittgrößen vor aber bei der klassischen Berechnung gibt es große Vereinfachungen.