Restart/Startspace Optimization - Bridge
- Anne Düchting (Unlicensed)
Goal of this Tutorial
Restart of an optimization
Selection of optimization parameters
Training:
You find all relevant data and files in the Example folder for this tutorial!
CAD Preparation: To use the symmetry function, the model must be centered in the coordinate origin along the symmetry plane.
Step 1: Create a new project
In a first step, you need to create a new project. All data (geometry and configuration) will be copied and saved directly in a new project folder, located in your workspace:
Start MSC Apex Generative Design 2019
Create a new project using the symbol
Enter a project name and save the project
Open the newly created project
To reduce the time to generate the optimization model, you can clone the project Symmetrical Optimization - Bridge and just adjust the model with the new parameters and stls
Step 2: Model generation
Upload all relevant stl files by clicking on the symbol in the objects/surfaces area
Select all stl files. In a startspace optimization you will also need the space you want to use as a start space. This can either be an optimization iteration/result from another optimization or an already design part you just want to adjust a bit.
In this case: buildSpace_MC_MainData_Loop_40, the 40th iteration of the Symmetrical Optimization - Bridge, is chosen. The optimization is in its middle stage with a medium resolution and is still in its finding stages. The force streams are visible but not yet fully defined and optimized.
The field at the bottom shows notifications to help you generate an optimization model
The uploaded objects are listed in the objects/surfaces area
For an optimization in which the startspace is meant to be changed during the further iterations, the space needs to be deleted from the project. This way the stl file stays in the project folder but the space won’t be included as a nondesign space in the optimization. If it would be considered as a nondesign space, the volume couldn’t be changed during the optimization which is not the purpose in a restart/startspace optimization.
Assign a Material to each object/surface and enter the specific values for the Young's Modulus (210e3) and poisson ratio (0.28) in the Material Editor
Activate the option design space for the relevant stl file. Only one volume can be selected as such.
In this case: Bridge - design-1
Step 3: Definition of boundary conditions
Go to the boundary conditions tab to enter the loads and fixations. For each boundary condition a name, a space and the specification of the boundary condition is entered as follows:
Name | Object | Direction | Value in N |
|---|---|---|---|
Force | Bridgestreet1 | y | 4000 |
Object "Bridgestreet1" experiences a force of 4000 N in y-direction (Force). The force of the whole bridge is 16.000 N. If you are using the symmetry option, the force must be adjusted to the calculation model. If only a quarter of the component is calculated (symmetry along the x and z axis), the force must also be quartered. The example already considers this restriction.
Name | Object | Direction |
|---|---|---|
Fixation1 | Bridgepillar11 | x, y, z (=0) |
Fixation2 | Bridgepillar21 | x, y, z (=0) |
Fixation3 | Bridgepillar31 | x, y, z (=0) |
Fixation4 | Bridgepillar41 | x, y, z (=0) |
A total of 1 force and 4 fixations should have been created as a result
All boundary conditions must be assigned to the load cases. The number of load cases can be changed using the "+" or "-" characters. The assignment of the boundaries to the load cases can be made in the boundary conditions or load cases area by selecting the different boundary conditions while the load case is activated for a restart/ a continuing optimization these will be the same as in the Symmetrical Optimization - Bridge.
Active in Loadcase1: Force, Fixation1, Fixation2, Fixation3 and Fixation4
Step 4: Definition of optimization parameters
Switch to the optimization area. You can find more information about the parameter selection here.
Choose the design type filigree
Enter the optimization goal stress: 50 MPa
Set the symmetry settings: YZ-Plane and XY-Plane
Open Result File Formats. The following result files should be activated:
stl File: results of each iteration in stl file format
stl Files Intersected: result of each iteration intersected with the design space in stl file format
ply Files with Stress: results with the information of stresses of each iteration (must be activated to show the results in the Visualization space)
ply Files with Displacement: results with the information of displacements of each iteration (must be activated to show the results in the Visualization space)
More information on result file formats here
All Inputs can be viewed and checked in the configuration file. The file should look like this.
For a restart some Expert Settings must be added to the configuration file as follows:
The iteration at which the function fOptimizer_switchAddRemove as well as the number of Iterations and stress levels are activated and added to the configuration file. You can always change the number of Iterations at which the function switchAddRemove is active, the number of resuolution levels, the number of iterations in each resolution level and the reached stressPercentGoal to influence the results and try out different options.
Please make sure only one .amendate file is in your project folder.
You can always change the design type, stress and solverMaxMemory to influence the results and try out different options. Further information here.
Step 5: Save the Project
Step 6: Starting the optimization and visualizing the results
If all data are correct, the optimization can be started and tracked in the results area.
All result iterations are displayed as soon as they are available. The progress of the optimization can also be monitored via the AMendate log file. Furtheremore you are able to stop the optimization in this selection area.
The warning "The following component is not considered in this iteration" is to be ignored in case of the symmetry constraint. Due to the symmetry, only a part of the component is used for the calculation and therefore only a part of the objects are used. The objects that are not considered are listed in the warning.
The optimization is finished after 64 iterations (optimizationtype: optimizing).
Step 7: Visualization of Stresses
The legend can be influenced using the slider. The function "Automatically set to local minimum and maximum" considers the stresses of each iteration and sets the values from the current iteration.
Step 8: Visualization of Displacements
The legend can be influenced using the slider. The function "Automatically set to local minimum and maximum" considers the displacements of each iteration and sets the values from the current iteration.
For a comparison have a look at the tutorial Symmetrical Optimization - Bridge. Here the setting for the design type normal were used. In this tutorial the parameters in Expert Settings were changed to the settings of the design type filigree for the last 30 iterations.
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