(API) extracting ground reactions results (Kz) underneath a panel

[Anonymous]

Hello,

I try to extract reaction value under panel #1 of my model with API (in VB) and don't figure out how to do it.

I know how to extract results values for nodes (PNorm) but not for the panel.

Does someone know how to do that ?

Thanks so much for your help!

[Rafal.Gaweda]

http://forums.autodesk.com/t5/robot-structural-analysis/api-sum-of-reactions-for-the-slab-on-elastic...

[Anonymous]

Thanks Rafal.

I know this macro which looks to me like running a nuclear plant to obtain 1 value.

The panel of the model has more than 800 nodes and there are hundred of load cases... the macro works but is very time consuming.

I would have some hope that there was a kind of direct method to obtain the value.

If this method doesn't exist in current API, I would suggest to add a proposal in "ideaStation".

Thanks.

[Artur.Kosakowski]

1. Define surface elastic support under a panel (instead of elastic soil definition in its thickness)

2. Select its nodes

3. Open table of reactions filtered to these nodes only

5. Copy Sum of val. fields from the bottom of the table to Excel

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

[Rafal.Gaweda]

Artur's approach by API (for elastic planar support) in attached example

See comments in code to adjust it before use

[Anonymous]

Thanks to both of you for your responses.

I'm still reviewing the first macro and have a question.

It works well but for a load, which is perpendicular to the slab on grade, the value obtained with the macro is differente than the value of Robot...

The value in Robot is 0 (as the load is perpendicular, it seems logical) whereas the value obtained with the macro is positive or negative.

Any idea on this ?

Thanks.

[Rafal.Gaweda]

I am afraid I do not understand.
First macro gets kz results for each Fe and then "integrates" them to have total panel kz. It has nothing to do with loads.

Send us robot example file to see what you mean.

[Anonymous]

sorry for my bad language... I will try to be more explicit!

I was refering to macro :"sum of reactions for the slab on elastic ground" :

http://forums.autodesk.com/t5/robot-structural-ana​lysis/api-sum-of-reactions-for-the-slab-on-elasti...

this macro give the ground reaction for the slab on elastic ground for a specfic load case.

The issue I have is:

- model : cantilever wall (indeed two slabs : one on ground and one slab vertical) ; slab on grade with elastic foundation coefficient defined, and horizontal spring on some nodes for tangent elasticity

- load case considered : earth pressure on the vertical slab (so only a horizontal load)

- result of reaction under slab on grade :

   - in Robot interface : 0

   - with macro : -324

I' a little bit stucked and I wonder why there is a difference ?

Extra question : can I defined with the API a tangent elasticity under a slab (Kx and Ky in kN/m3) ?

Thanks.

[Rafal.Gaweda]

The difference comes from kz defintion way.

If kz is defined in panel thickness defintion - results are available as "Soil reaction - K" map or results in Plates and Shell results table and not for reactions.

The macro mentined by you works for kz defined in panel thickness.

The other macro work for kz defined in Planar supports defintion.

[Rafal.Gaweda]

can I defined with the API a tangent elasticity under a slab (Kx and Ky in kN/m3) ?

No.

[Anonymous]

Thanks for your quick responses ! (and too bad for tangent elasticity... maybe in next RSA version??)

If kz is defined in panel thickness defintion - results are available as "Soil reaction - K" map or results in Plates and Shell results table and not for reactions.

The macro mentined by you works for kz defined in panel thickness.

It is what I do : I compare value obtained in "plate and shell - reaction kz" and value obtained with the macro (and should be the same value ?)

Here attached is the file, maybe you could run the 2 methods to obtain reaction values ? and tell me if you notice the same difference ?

Let me know.

Thanks.

[Rafal.Gaweda]

I think you refer to case 7

The assumption made by me in this macro is that soil pressure is uniform in each FE. But in fact it is not.

So in this model the difference is 10 kN vs 0 kN

If you refine mesh (for example make it 3 times denser) the difference is 2 kN vs 0 kN.

[Anonymous]

Ok thanks, I understand.

Which value PNorm is retruning ? average ? min ? max ?

Furthermore, in RSA, there is no value for a moving load case. How can I obtain a value ?

Thanks.

[Rafal.Gaweda]

Which value PNorm is retruning ? average ? min ? max ?

Average

Furthermore, in RSA, there is no value for a moving load case. How can I obtain a value ?

??????????????

[Anonymous]

Hello,

see attached exemple:

I created a moving load (case #8) but in panel results, there is no result for "moving load +" and "moving load -" (neither for moving load itself).

Why ?

I expect to have, for "moving load +" and ""moving load -", the maximum and minimum value of kz reaction under the slab for the moving load. But it isn't.

what's wrong ?

Running the excel macro (on "moving load +" or "moving load -") gives results but, I think, without physical meaning. (maximum or minimum value for every FE without concomitance).

Thanks.

[Rafal.Gaweda]

I created a moving load (case #8) but in panel results, there is no result for "moving load +" and "moving load -" (neither for moving load itself).

?????

 Running the excel macro (on "moving load +" or "moving load -") gives results but, I think, without physical meaning.

Yes, it just makes a sum of values but values may come from different vehicle positions.