Obtain Element Stresses

1

Hi,

Is it possible to obtain each element nodal stress tensor result ? I want to calculate nodal stresses manually by using each node parent element stresses.

Ex:

Element-1 : Node 1: Sx : 1 , Sy : 1, Sz : 1 Sxy : 1 …

Element-1 : Node 2: Sx : 1 , Sy : 1, Sz : 1 Sxy : 1 …

Element-1 : Node 3 Sx : 1 , Sy : 1, Sz : 1 Sxy : 1 …

Element-1 : Node 4 Sx : 1 , Sy : 1, Sz : 1 Sxy : 1 …

Ex2:
Element-1 : Node 1: Sx : 1 , Sy : 1, Sz : 1 Sxy : 1 …

Element-2 : Node1: Sx : 2 , Sy : 1, Sz : 1 Sxy : 1 …

Element-3 : Node 1 Sx : 3 , Sy : 1, Sz : 1 Sxy : 1 …

Element-4 : Node 1 Sx : 4 , Sy : 1, Sz : 1 Sxy : 1 …

Node 1 Stresses Sx = (1 + 2 + 3 + 4)/4

2

CalculiX provides averaged nodal stresses in the .frd file but you can also write integration point stresses to the .dat file (using *EL PRINT).

3

Thank you, But I do not want to integration points because it is necessary to extrapolate this stresses. Is it possible to my example ?

4

Then you can use the stresses from the .frd file directly (query them in some postprocessor) but they are averaged from all elements sharing a given node. You can avoid this averaging if you use the separate.py script from here: CalculiX-Examples/Scripts at master · calculix/CalculiX-Examples · GitHub

5

I’m not sure I understand your question. From your Ex2, it seems like you are asking for the extrapolated, but not averaged nodal stresses (@Calc_em posted an answer).
The nodal stresses CalculiX provides are extrapolated and then averaged stresses from the integration points. So if you are looking for the “most accurate” stress information, you should use the stresses at the integration points (in the .dat file, again as @Calc_em already mentioned).

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