8 integration points in dat using cps3 and cps4 elements for plane stress

1

Hey,

I understand for 2d analysis ccx converts the model to 3d, however looking at the dat file i have non zero stress in the z direction. how can i control the integration points. This is my output.

*MATERIAL,NAME=steel
*ELASTIC, TYPE=ISOTROPIC
200000, 0.3
*DENSITY
7750
*SOLID SECTION, ELSET=ALL_ELEMENTS, MATERIAL=steel

*BOUNDARY
base_nodes,2,0
2,1,2,0

*STEP
*STATIC, SOLVER=SPOOLES

*BOUNDARY
displacement_nodes,2,1

*EL PRINT,ELSET=ALL_ELEMENTS
S,E,ENER
*NODE PRINT,NSET=ALL_NODES
U
*NODE PRINT,NSET=base_nodes
RF
*NODE FILE,GLOBAL=YES
U,RF
*EL FILE
S,E,ENER

*END STEP

and an example of my elements
1353, 1410, 1423, 1438, 1447
*ELEMENT, type=CPS3, ELSET=Surface4002
1354, 1, 178, 1463
1355, 1, 1463, 1464
1356, 1, 1464, 1465
1357, 1, 1465, 1466
1358, 1, 1466, 1467
1359, 1, 1467, 142
*ELEMENT, type=CPS4, ELSET=Surface4002
1360, 178, 179, 1468, 1463
1361, 1463, 1468, 1469, 1464

thank you

2

CPS3 is expanded to C3D6 (linear wedge) so it has 2 integration points. CPS4 is expanded to C3D8 (linear hexahedron) so it has 8 integration points. Indeed those elements may have non-zero stresses in the thickness direction: Discrepancy in Element Stiffness Matrix Output using Substructure Approach - #29 by vicmw

3

Thank you for the information and link, is there a method to output the element stress tensor? Or a method to know the coordinatos of the element integration points?

4

This will write integration point coordinates and stress tensor components to the .dat file:

*EL PRINT, ELSET=elset_name
COORD, S
5

Thank you,

*WARNING reading *EL PRINT: label not applicable
or unknown;
*ERROR reading *EL PRINT. Card image:
COORD,S,E,ENER
is this a common error?

6

Is it defined lexactly like this (of course, the elset name can be different) ?

*EL PRINT, ELSET=EALL 
COORD,S,E,ENER

This syntax is correct and shouldn’t cause any errors. Maybe you have a typo somewhere (e.g. in ELSET). Is the keyword placed within the step definition (between *STEP and *END STEP keywords) ?

1 Like
7

yeah I am not sure, it works fine without coord. Unless you can see anything in this?

*STEP
*STATIC, SOLVER=SPOOLES

*BOUNDARY
displacement_nodes,2,1

*EL PRINT,ELSET=ALL_ELEMENTS
COORD,S,E,ENER

*NODE PRINT,NSET=ALL_NODES
U

*NODE PRINT,NSET=base_nodes
RF

*NODE FILE,GLOBAL=YES
U,RF
*EL FILE
S,E,ENER

*END STEP

8

Could it be the installed version of CCX i am currently using the bconverged ccx 2.10 Download bConverged?

9

I updated CCX, works fine. thanks for the help