Tested with CGX 2.19 / CCX 2.19
- Modal analysis with automatic generation of mode shape animations
- Parametric model
- Inspired by a CalculiX forum post
| File | Contents |
|---|---|
| pre.fbl | Preprocessing script for CGX |
| modal.inp | CCX input |
| shapes.fbl | CGX script for postprocessing (mode shape movies) |
| test.py | Python script to run the full simulation |
The model is a disk with reinforced rim (revolution of an L shaped section). It could be created in exactly this way but here the focus was on getting a mesh with limited element distortion.
The sequence of geometry generation is as follows:
- Top-down build of the inner quarter circle surface with radius
ri - Axial extrusion into thickness
t1of the plate - Radial extrusion of the perimeter surface by the radial thickness of the rim
dr - Axial extrusion by the axial thickness of the rim
t2
As non-symmetric mode shapes are to be expected, the quarter model is expanded by mirror copy and merge.
It is meshed with C3D8I elements (8 node hexaeder with incompatible shape functions).
| Parameter | Value | Description |
|---|---|---|
ri |
40 | Inner radius of the rim in mm |
dr |
2 | Radial thickness of the rim in mm |
t1 |
2 | Thickness of the disk in mm |
t2 |
3 | Thickness of the rim in mm |
Set the appropriate values for the parameters in pre.fbd
Generate the model using
> cgx -b pre.fbl
Run the analysis using
> ccx modal
12 mode shapes are calculated, 6 of them are rigid body motions due to the fully unconstrained model.
Running
> cgx -b shapes.fbl
creates animated gifs for the individual mode shapes. Here we only show the non-rigid modes.
