Tested with CGX 2.19 / CCX 2.19
Model based on the official ccx example beamcr.inp but with modified material parameters and load application
- Large displacements
- Visco-elastic material
- load application via
*couplingwith*distributing
| File | Contents |
|---|---|
| pre.fbd | CGX input for preprocessing |
| solve.inp | CCX input (constant force) |
| solve2.inp | CCX input (constant true stress) |
| peeq.plt | Gnuplot script for the creep curve (strain) |
| disp.plt | Gnuplot script for the creep curve (displacement) |
| test.py | Python script for the complete analysis |
| Parameter | Value | Meaning |
|---|---|---|
width |
1 | cross section dimension in mm |
length |
8 | length in mm |
le |
1 | node distance |
The parameters are defined in pre.fbd. The mesh and the sets are generated using
> cgx -b pre.fbd
The model consists of a bar of cross section 1 x 1 mm and 8 mm length (longitudinal direction Z). It is fixed at z = 0 in z-direction while allowing for deformation in x and y directions.
There are two versions of load application:
- solve.inp as a constant concentrated force to the control node of surface
Szl(creating constant total force) - solve2.inp as a constant negative pressure to surface
Szl(creating constant true stress)
Fully integrated 20-node elements are used, because reduced integration would lead to hourglassing with just a single element over the cross section.
The material parameters are taken from literature and represent magnesium alloy AZ91 at 200°C.
The simulation consists of a *visco step of 6.7 hr (constant total force) or 20 hr (constant true stress) duration.
> ccx solve
The simulation doesn't reach the designated total time because of excessive creep rate when the cross section becomes too small.
> monitor.py solve
> ccx solve2
The solver history can be documented with
> monitor.py solve2
The equivalent creep strain is written to the .dat file.
This is converted to a tabular text file suitable for gnuplot.
> dat2txt.py solve
> dat2txt.py solve2
> gnuplot peeq.plt
Equivalent plastic strain and deformed shape of the profile:
