Tested with CGX 2.16 / CCX 2.15
- Frequency response analysis
- 2-Mass oscillator
- Mass element faked using beam element and appropriate constraints.
- Simulation with real mass elements fails because the eigenvalue solver can't handle small systems.
| File | Contents |
|---|---|
| run.fbd | Top level control script for CGX |
| MS.inp | Input for CCX |
| runM.fbd | Top level control script for CGX, discrete mass |
| MSM.inp | Input for CCX, discrete mass |
| V.gnu | Gnuplot script for the response function |
| test.py | Python script to run the full simulation |
The system consists of two rigid bodies connected by springs and dashpots.
| Parameter | Value |
|---|---|
| k | 10 N/mm |
| m | 7.8 mg |
| c | 0.000001 N/(m/s) |
Run the analysis:
> cgx -b run.fbd
There is no cgx-based preprocessing. The model is entirely defined within the input file MS.inp.
Springs and dashpots are represented by the appropriate discrete elements,
the masses are represented by beam elements which are rigidized by an equation linking their nodes.
First, a *frequency step is performed and then a *steady state dynamics step.
> ccx MS
Mode shapes
Magnitude and phase plot of the response (displacement of the masses)
There is no cgx-based preprocessing. The model is entirely defined within the input file MSM.inp.
Springs and dashpots are represented by the appropriate discrete elements,
the masses are represented by mass elements (new in 2.12).
> cgx -b runM.fbd
The simulation runs but the results are unreliable, because the eigensolver Arpack is not suited for small systems.