Tested with CGX 2.19 / CCX 2.19
- Large displacements
- Plasticity
- Buckling with imperfection (a small internal pressure)
- Shell elements
| File | Contents |
|---|---|
| pre.fbd | Pre-processing script for CGX |
| post.fbd | Post-processing script for CGX |
| Kasten.inp | CCX input |
| df.gpl | Gnuplot input for force-displacement curve |
Reference solution for elastic limit (without buckling)
The parameters can be changed in pre.fbd
| Parameter | Value | Meaning |
|---|---|---|
lx |
100 | width in x-direction in mm |
ly |
100 | width in y-direction in mm |
lz |
150 | height in mm |
nd |
7.8 | target node distance in mm |
disp |
20 | displacement in mm |
> cgx -b pre.fbd
Geometry and sets
> ccx Kasten
> monitor.py Kasten
Mesh and set definitions
*include,input=all.msh
*include,input=lower.nam
*include,input=upper.nam
Clamping of the upper and lower edge
*boundary
Nlower,1,6
Nupper,1,6
Material definition (elasto-plastic)
*MATERIAL,NAME=Steel
*ELASTIC
210000,.3
*plastic
100,0
200,0.3
300,1
*DENSITY
7.8E-9
Material and shell thickness assignment
*SHELL SECTION,ELSET=Eall,MATERIAL=Steel,offset=0
1
Step 1: Internal pressure (imperfection)
*STEP,nlgeom
*STATIC
*dload
*include,input=all.dlo
*el file
S
*node file
U
*end step
Step 2: Axial compression (prescribed displacement)
*step,nlgeom
*static
0.05,1,,0.05
*boundary
*include, input=disp.inc
*el file
S,PEEQ
*node file
U
*node print,totals=only,nset=Nupper
U,RF
*end step
> cgx -b post.fbd
Magnitude of the displacement due to pressure application (imperfection). Max. deflection is approximately 10% of the sheet thickness.
Deformed geometry after collapse. The left image shows the result for the parameters as in the files. The right image has double the displacement and a target element size of 3 mm.
Vertical displacement and plastic equivalent strain:
Force-displacement plots. Left: full history, right: detail of transition to collapse. Note that 40 kN is the elastic limit in the linear analysis.
