Restart, StartSpace & Influencing the designs
- Anne Duechting-Rotsch
Switch to former static schedule
The progression control can be deactivated and switched back to the former known optimisation method of a static schedule with the following command:
Input Commands | Explanation |
|---|---|
schedule.prefabricated.progressionControl = Static | Static optimisation schedule with predefined number of iterations depending on the chosen Strut Density and Shape Quality |
Influencing the Convergence Detection
To influence the optimisation parameters even further, changes to the safety coefficient of the convergence detection can be made in each resolution level. These settings overwrite the selection of the Strut Density and the Shape Quality as they are only default settings.
schedule.level.1.iterationCount = 0 schedule.level.1.eventSafetyCoefficient.initial= 0.6 |
The table gives an overview of the default settings:
General Optimisation without a manufacturing method:
Level | Event Safety Coefficient |
|---|---|
Level 1 | 0.3 |
Level 2 | 0.3 Mass Target & Strut Density Dense: 0.757 Mass Target & Strut Density Medium: 0.841 Mass Target & Strut Density Sparse: 0.921 |
Level 3 | 0.6 Mass Target & Strut Density Dense: 0.879 Mass Target & Strut Density Medium: 0.928 Mass Target & Strut Density Sparse: 0.970 |
Level 4 | 0.9 Mass Target & Strut Density Dense: 0.943 Mass Target & Strut Density Medium: 0.969 Mass Target & Strut Density Sparse: 0.989 |
Level 5 | 0.95 Mass Target & Strut Density Dense: 0.981 Mass Target & Strut Density Medium: 0.991 Mass Target & Strut Density Sparse: 0.997 |
Level 6 | 1.0 |
Optimisation with casting manufacturing method:
Level | Event Safety Coefficient |
|---|---|
Level 1 | 0.3 |
Level 2 | 0.3 Mass Target & Strut Density Dense: 0.827 Mass Target & Strut Density Medium: 0.892 Mass Target & Strut Density Sparse: 0.951 |
Level 3 | Strut Density Dense: 0.95 Strut Density Medium: 0.75 Strut Density Sparse: 0.95 Mass Target & Strut Density Dense: 0.995 Mass Target & Strut Density Medium: 0.996 Mass Target & Strut Density Sparse: 0.997 |
Level 4 | 1.0 |
Level 5 | 0.95 |
Level 6 | 1.0 |
The software uses six resolution levels from coarse to fine (level 1: coarse - level 6: fine). To remove or skip a resolution level the iteration count value can be set to 0.
To set up these additional parameters, the Input Commands need to be added to the optimisation model in the Advanced User Settings text field.
Restart (Start Space)
With the Advanced User Settings a Restart is possible. A Start Space needs to be chosen with which the optimisation will re/start.
Therefore, an already optimised STL-file is needed as a Start Space. This file can be exported directly from the post processing and selected as a Start Space by clicking on the browse button. The unit of the exported STL-file needs to be in meters (SI-Units).
For a restart the starting resolution level has to be input as well as the event safety coefficient for the progression control.
schedule.startCandidate.candidate = StartCandidate.stl schedule.level.1.iterationCount = 0 schedule.level.1.eventSafetyCoefficient.initial= 0.6 … schedule.level.5.iterationCount = 5 schedule.level.5.eventSafetyCoefficient.initial= 1.0 |
Have a look at the tables above for specific event Safety Coefficient values.
This way a two-stage optimisation is also possible. For a two-stage optimisation the resolution level and input parameters have to be chosen wisely and will need some fine tuning.
A Start Space can be marked as a Non-Design Space, thus the Start Space cannot be removed during the optimisation and will be part of the final design. Therefore, the following command needs to be added:
geometry.StartCandidate.path = StartCandidate.stl |
Influencing the number of iterations & the Strut Density
To influence the optimisation parameters even further, changes of the number of iterations and number of resolution levels can be made. These settings overwrite the selection of the Strut DensityStrut Densityand the Shape Quality as they are only default settings for the ones described here. The table gives an overview of the default settings:
General Optimisation without a manufacturing method:
Input Commands | Explanation |
|---|---|
schedule.level.1.iterationCount = 16 schedule.level.2.iterationCount = 8 schedule.level.3.iterationCount = 8 schedule.level.4.iterationCount = 17 schedule.level.5.iterationCount = 15 | Specify how many iterations are calculated at which resolution level.
|
Optimisation with casting manufacturing method:
Input Commands | Explanation |
|---|---|
schedule.level.1.iterationCount = 20 schedule.level.2.iterationCount = 40 schedule.level.3.iterationCount = 20 | Specify how many iterations are calculated at which resolution level.
|
The software uses five resolution levels from coarse to fine (level 1: coarse - level 5: fine). The number behind the level indicates the number of iterations calculated on this resolution level. To remove or skip a resolution level the value can be set to 0.
To set up these additional parameters, the Input Commands (left side of the table) need to be added to the optimisation model in the Advanced User Settings text field. In the picture below an example is shown. By adding these Advanced User Settings, the first (coarse) resolution level will be skipped and the optimisation starts directly at the second level. You might want to add more iterations to the remaining levels to give the optimisation the chance to reduce the material accordingly and reach a convergence in each level.
For a general optimisation without a manufacturing method the difference between the Strut Densities is done by an internal geometry smoothing of the elements in the background. Depending on the intensity of the smoothing more, smaller struts (dense) or less, thicker struts (sparse) can be created for the same model & boundary conditions. As long as the later levels (level 4 and level 5) are used these settings also work for different iteration numbers.
For an optimisation with casting as the manufacturing method the difference between the Strut Densities is done by different relative stress target per resolution level.
Restart (Start Space)
With the Advanced User Settings a Restart is possible. A Start Space needs to be chosen with which the optimisation will re/start.
Therefore, an already optimised STL-file is needed as a Start Space. This can be exported directly from the post processing and be selected as a Start Space by clicking on the browse button. Therefore, the unit of the exported STL-file needs to be in meters (SI-Units). In most cases the Strut Density and Shape Quality settings must be changed as well using the Advanced User Settings. For a restart the same resolution level and number of to be completed iterations have to be filled in. You can find a Tutorial to how to perform a Restart here.
This way a two-stage optimisation is also possible. For a two-stage optimisation the resolution level and number of iterations must be chosen wisely and will need some fine tuning.
A Start Space can be marked as a Non-Design Space, thus the Start Space cannot be removed during the optimisation and will be part of the final design. Therefore, the following command need to be added as well:
geometry.StartCandidate.path = StartCandidate.stl |
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