This section presents an example procedure of creating a geometrical and numerical model to be optimized with ProTOp. The described steps and procedures are valid for PTC® Creo®.
The domain of the bracket model is shown in the figure below. It consists of one fixed and one optimization volume region. The optimization objective is to reduce the volume of the bracket rib to 30% of its initial volume. The fixed bracket volume remains unchanged during the optimization task. Boundary conditions and three load cases are plotted in the following figure.
Create a part called Bracket, as shown in the figure. This will be the domain of the problem.
Use the Simulate application of Creo® as a FEA workspace in order to prepare the input model for the optimization task.
Check the FEM Mode checkbox to start the optimization or create the PTC® FEM Neutral Format file (*.FNF file) for the third-party finite element solvers and applications.
Define a list of materials used in the model. One material has to be defined for each volume region. Each region will be associated with its own material properties, optimization parameters and geometric restrictions.
Define material names and properties in the Material Definition dialog box.
The names of the materials in the model can be any combination of alphanumeric characters.
Define the optimization volume region by creating the volume VOLUME01.
Define the boundary conditions (supports and loads) for the FEA.
Fix the displacements Dx=0, Dy=0 and Dz=0 on the back side surface, (WCS coordinate system).
Prescribe the surface load in the LoadSet1 on the bottom front surface Fy=-10kN (WCS coordinate system).
Prescribe the edge loads in the LoadSet2 on the left and right front vertical edges, left edge Fy=+5kN, right edge Fy=-5kN, (WCS coordinate system).
Prescribe the edge loads in the LoadSet3 on the left and right front vertical edges, left edge Fy=-5kN, right edge Fy=+5kN, (WCS coordinate system).
Assign the material STEEL to the bracket rib, defined as a volume region VOLUME.
Assign the material STEEL_FIX to the component Bracket.
Define the component mesh size in the Maximum Element Size Control dialog box, Element Size is 10.
Refine the mesh size in Maximum Element Size Control dialog box. Element Size is 5 in the optimization volume VOLUME01.
Mesh the model and check its quality.
Create the load cases
Define the load case BrackedLoadCase1 consisting of the ConstraintSet1 and LoadSet1.
Define the load case BrackedLoadCase2 consisting of the ConstraintSet1 and LoadSet2.
Define the load case BrackedLoadCase3 consisting of the ConstraintSet1 and LoadSet3.
Run ProTOp
Note. This option is only available with Creo® integration of ProTOp.
Run FEM Analysis (Manual option)
Create the FEM Neutral Format file (*.FNF file) for the single load case BrackedLoadCase1 optimization task. The *.FNF file will be stored in the analysis subdirectory BrackedLoadCase1 on the working directory. The same working directory can be used for the optimization process.
Create the FEM Neutral Format file (*.FNF file) for the multi-load cases BrackedLoadCase1, BrackedLoadCase2 and BrackedLoadCase3 optimization task.
Define the case-study working directory by Select Name or Enter Name in the case of a multi-load cases optimization task, the *.FNF will be stored in this subdirectory of the working directory. The same directory can be used for the optimization process.
NOTE. Although running ProTOp directly from Creo is simpler, the Manual option is often the preferred way of exporting to FNF format because it offers more control over the meshing process and the export of auxiliary coordinate systems.