Topic: Error in LoadElementSelection_beforeStep.bas

Hello!

I get a message after starting analysis from GiD:

Error in base file 'C:/Program Files/GiD/GiD 14.0/problemtypes/Atena/Execute/../include.src.bas/LoadElementSelection_beforeStep.bas' at line number 67: GlobalNodes can't be used in this context. There is no NumFace

The model is available by the link: https://drive.google.com/open?id=1Dnlvm … jfK48is_P4

Re: Error in LoadElementSelection_beforeStep.bas

Dear Pavlo,
1. I don't get the target of your model?

2. Assigning the same material to both 3D and 2D elements does not make much sense (choose Idealisation: Plane Stress or Plane Strain at the Element Geometry tab for membranes). However, if I remember correctly, if you use a 3D material for a 2D element, it gets interpreted like Plane Stress with 1m thickness - is that your intention?

3. Having several separate structures in a single model is not something the numerical solution is designed for.

4. If you only have line supports on 1 edge, the rotational DoF around that edge remains free - a rigid-bopdy motion mode unblocked.

On meshing, I get the message:

Warning: condition 'Load_Force_for_Surface' has flag 'on face elements' and it is applied 'on body elements' for the entity 1

- I suppose this kind of load is only for Surfaces belonging to Volumes in a 3-dimensional model. Maybe Zdenek can explain?

Regards.

3 (edited by pavlo 2019-08-14 15:43:22)

Re: Error in LoadElementSelection_beforeStep.bas

Dear Dobromil,

1. The target is to get an alternative solution of a FE model with inconsistent mesh connected with mster-slave conditions. We've made a comparison of 2 different programs and wanted to have 1 more example. The comparison report is here: https://drive.google.com/open?id=1Y-FKc … 9lyhrRK9vJ
2. I changed to SHELL Concrete-Steel type with base material Elastic.

dpryl wrote:

if you use a 3D material for a 2D element, it gets interpreted like Plane Stress with 1m thickness - is that your intention?

No, I wanted to get bending out of slab plane.
3. This is a linear problem so I don't think it creates any trouble.
4. You are right, I just forgot to lock these DoF.
5.

dpryl wrote:

I suppose this kind of load is only for Surfaces belonging to Volumes in a 3-dimensional model

I redefined the load with the use of self weight.

However, now the model cannot reach convergency... I don't understand why since all materials are elastic... I assigned all possible restraints but it doesn't help... Would you please check revised model: https://drive.google.com/file/d/1PWGfYW … sp=sharing

Re: Error in LoadElementSelection_beforeStep.bas

Dear Pavlo,

ad 3.: combining several independent structures in a single model is not a good idea. The solution methods are not being developed for this, at least in ATENA (and probably in most civil engineering FEM packages). Even if everything is linear (and the geometry is NOT in ATENA), stiffness differences make the combined system worse conditioned compared to the separate ones. Moreover, it can be hard to identify which of the separate structures has a problem.

Ad 4., 5.: Looking at the model with 1 and 3 surfaces, I see no connection among the 3 surfaces (just between the 3 and the large one)?

I am asking our colleague responsible for the ATENA-GiD scripts if/how one can connect the rotational DoFs between neighbouring 2D shells.

Regards.