With *DEFORMATION PLASTICITY, stiffness depends on the orientation of the element coordinate system but I think it’s an isotropic material that should be independent of orientation.
In this example, I expect Y-displacement to be equal on both elements (eg. at nodes 1 and 9) but it’s about 20% different. At lower loads, the difference vanishes and at higher loads it fails to converge, so maybe that’s related.
CCX version 2.23
** Generated by Mecway 33
*NODE
1,0.001,0.001,0
2,0.001,0.001,0.0002
3,0,0,0.0002
4,0,0,0
5,0.001,0,0.0002
6,0.001,0,0
7,0,0.001,0
8,0,0.001,0.0002
9,0.003,0.001,0
10,0.003,0.001,0.0002
11,0.002,0,0.0002
12,0.002,0,0
13,0.003,0,0.0002
14,0.003,0,0
15,0.002,0.001,0
16,0.002,0.001,0.0002
*ELEMENT,TYPE=C3D8I
1,4,6,1,7,3,5,2,8
2,12,14,9,15,11,13,10,16
*ELSET,ELSET=1
1
*ELSET,ELSET=2
2
*SURFACE,NAME=PRESSURE_FACES
2,S5
1,S5
*ORIENTATION,NAME=O3
0,1,0,-1,0,0
*MATERIAL,NAME=MATERIAL
*DEFORMATION PLASTICITY
200000000000,0,150000000,3.4,1.2
*SOLID SECTION,ELSET=1,MATERIAL=MATERIAL
*SOLID SECTION,ELSET=2,MATERIAL=MATERIAL,ORIENTATION=O3
*BOUNDARY
3,2,,0
4,1,,0
4,2,,0
4,3,,0
5,2,,0
6,2,,0
6,3,,0
11,2,,0
12,1,,0
12,2,,0
12,3,,0
13,2,,0
14,2,,0
14,3,,0
*STEP,NLGEOM=YES,INC=100
*STATIC
1,1,1E-06,0
*DSLOAD
PRESSURE_FACES,P,-400000000
*NODE FILE,GLOBAL=YES
U
*END STEP