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HS-4410: Frequency Maximization Application

HS-4410: Frequency Maximization Application

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HS-4410: Frequency Maximization Application

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In this tutorial you will learn how to use the objective function type MaxMin through a frequency maximization application..  The sample base input template plate.tpl can be found in <hst.zip>/HS-4410/ and copied to your working directory.

The objective is to maximize the minimum frequency of the first five modes of a plate.  The input variables are the thickness of each of the three components, defined in the input deck via the PSHELL card.  The thickness should be between 0.05 and 0.15; the initial thickness is 0.1 (shown below).  The optimization type is size.

hs_4225_Double symmetric plate model

Figure 1: Double symmetric plate model

hmtoggle_plus1greyStep 1: Perform the Study Setup
1.Start HyperStudy.
2.To start a new study, click File > New from the menu bar, or click files_new_hst2 on the toolbar.
3.In the HyperStudy – Add dialog, enter a study name, select a location for the study, and click OK.
4.Go to the Define models step.
5.Add a Parameterized File model.
a.From the Directory, drag-and-drop the plate.tpl file into the work area.

hs_4410_drag_drop_model

b.In the Solver input file column, enter plate.fem. This is the name of the solver input file HyperStudy writes during any evaluation.
c.In the Solver execution script column, select OptiStruct (os).

hs_1020_define_models

6.Click Import Variables. One input variable is imported from the plate.tpl resource file.
7.Go to the Define Input Variables step.
8.Review the input variable's lower and upper bounds ranges.
9.Go to the Specifications step.

 
hmtoggle_plus1greyStep 2: Perform the Nominal Run
1.In the work area, set the Mode to Nominal Run.
2.Click Apply.
3.Go to the Evaluate step.
4.Click Evaluate Tasks. An approaches/nom_1/ directory is created inside the study directory. The approaches/nom_1/run__00001/m_1 sub-directory contains the plate.out file, which is the result of the nominal run, and will be used during the Optimization.
5.Go to the Define Output Responses step.

 
hmtoggle_plus1greyStep 3: Create and Define Output Responses
1.Click Add Output Response.
2.In the HyperStudy - Add dialog, add five output responses.
3.In the Expression column of Response 1, click hs_popupdialogicon.
4.In the Expression Builder, click the File Sources tab.
5.Click Add File Source.
6.In the HyperStudy - Add dialog, add one Solver output file.

solver_output_file

7.In the File column of Vector 1, click hs_popupdialogicon.
8.In the Vector Source dialog, navigate to the approaches/nom_1/run__00001/m_1 directory and open the plate.out file.
9.Define Vector 1 as the volume of the plate by selecting the options indicated in the following image from the Type, Request, and Component fields.

hs_4225_vector source

10.Click OK.
11.Click Insert Varname. The expression v_1[0] appears in the Evaluate Expression field.
12.Click OK.
13.Repeat steps 3 through 12 for Response 2 through Response 5. Define each Vector by selecting the options indicated in the image below from the Type, Request, and Component columns.

hs_4225_evaluate expression

14.Click Evaluate Expressions to extract the output response values.

This completes the study setup. You can now proceed to the desired study type (DOE, Optimization, or Stohastic study).

 
hmtoggle_plus1greyStep 4: Run an Optimization Study
1.In the Explorer, right-click and select Add Approach from the context menu.
2.In the HyperStudy - Add dialog, select Optimization and click OK.
3.Go to the Select Input Variables step.
4.Review the input variable's lower and upper bound ranges.
5.Go to the Select Output Responses step.
6.Click Add Objective.
7.In the HyperStudy - Add dialog, add five objectives.
8.Define Objective1 through Objective 5 by selecting the options indicated in the image below from the Apply On column.

hs_4225_apply on

9.Maximize the minimum for all five objectives by selecting MaxMin from the Type column.
10.In the study Setup, Define Output Responses step, copy the values for all five output responses in the Value column.

hs_4410_copy_table

11.In the Optimization, Select Output Responses step, paste the values into the Reference Value column.

hs_4225_copy initial value

12.Click Apply.
13.Go to the Specifications step.
14.In the work area, set the Mode to Adaptive Response Surface Method (ARSM).
Note:Only the methods that are valid for the problem formulation are enabled.
15.Click Apply.
16.Go to the Evaluate step.
17.Click Evaluate Tasks.

 
hmtoggle_plus1greyStep 5: View the Iteration History of an Optimization Study
1.Click the Iteration Plot tab to monitor the progress of the Optimization iteration.
2.Using the Channel selector, select all five objectives. The Optimization iteration history of Objective 1 through Objective 5 is plotted.

hs_4225_function vs iteration

 

 

 

See Also:

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