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History MSE

In this example time history curves are used to calibrate directly experiment vs. simulation curves.

Solution with LS-OPTui

Document Actions

Solution with LS-OPTui

Solvers

Solvers

Open LS-OPTui.

Solvers Panel

  1. Select the Solvers panel.
  2. For Command select your LS-DYNA executable
  3. For Input File browse the file foam1.k in your directory.
  4. Enter the Name of Analysis Case, e.g. Case1.
  5. Push the Add button to create a new analysis case.
solver1.png

 

Variables

Variables

Define the Variables

  1. Select the Variables panel.
  2. Switch the YMod Type from Constant to Variable.
  3. Enter 500000 for the Minimum.
  4. Enter 2000000 for the Maximum.

 

 var_ymod1.png
  1. Switch the Yield Type from Constant to Variable.
  2. Enter 500 for the Minimum.
  3. Enter 2000 for the Maximum.

 

 var_yield1.png

Histories

Histories

Extract History

  1. Select the Histories panel.
  2. From the possible histories select NODOUT.
  3. Type in the node ID: 296.
  4. For Component select Displacement.
  5. For Direction select Z Component.
  6. Type in Disp1 for the History Name.
  7. Push the Add button.
history_disp1.png
  1. From the possible histories select RCFORC.
  2. Type in for Interface ID: 1.
  3. For Component select Z slave force.
  4. Type in Force1 for the History Name.
  5. Push the Add button.
history_force1.png
  1. From the possible histories select Crossplot.
  2. For z(t) type in -Disp1 (negative Disp1).
  3. For F(t) type in Force1.
  4. Type in F_vs_d as History Name.
  5. Push the Add button to create a new history.
history_f-vs-d1.png
  1. From the possible histories select File.
  2. Push the Browse button to find the file Test1.txt from your main directory.
  3. Type in FILE1 as History Name.
  4. Push the Add button to create a new history.
 		history_test-file1.png

Responses

Responses

Define the Responses

  1. Select the Responses panel.
  2. From the possible response types select: MeanSqErr.
  3. For Target curve select FILE1.
  4. For Computed curve select F_vs_d.
  5. Type in the label MSE for Response Name.
  6. Push the Add button.
response_mse1.png

Objective

Objective

Objective

  1. Select the Objective panel.
  2. Select MSE from Response as the objective function.
  3. Leave the default 1.0 for Weight.
objective_mse1.png

Run

Run

Run the Optimization

  1. Select the Run panel.
  2. For Number of iterations enter 3.
  3. Push the Run button to start the optimization. (Save the project as com.mse_history)
run1.png

Com-file

Com-file

The created command file may look like this:

"history based MSE"
$ Created on Fri Jan 11 10:55:50 2008
solvers 1
$
$ WARNING -- NO RESPONSES ARE DEFINED
$
histories 4
$
$ DESIGN VARIABLES
$
variables 2
 Variable 'YMod' 700000
  Lower bound variable 'YMod' 500000
  Upper bound variable 'YMod' 2e+06
 Variable 'Yield' 1500
  Lower bound variable 'Yield' 500
  Upper bound variable 'Yield' 2000

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$      OPTIMIZATION METHOD   
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
Optimization Method SRSM

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$      SOLVER "Case1"
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$ DEFINITION OF SOLVER "Case1"
$
 solver dyna960 'Case1'
  solver command "/home/prak1/LS-DYNA/ls971_s_7600_1224_ia32_redhat90"
  solver input file "/home/prak1/LS-OPT/beispiele/parameter_identification/history_based/foam1.k"
  solver check output on 
  solver compress d3plot off 
$ ------ Pre-processor --------
$   NO PREPROCESSOR SPECIFIED
$ ------ Metamodeling ---------
  solver order linear
  solver experiment design dopt
$ ------ Job information ------
$
$ WARNING - NO RESPONSES DEFINED FOR SOLVER "Case1"
$
$
$ HISTORIES FOR SOLVER "Case1"
$
 history 'Disp1' "BinoutHistory -res_type nodout  -cmp z_displacement -id 296"
 history 'Force1' "BinoutHistory -res_type RCForc -cmp z_force  -id 1  -side SLAVE"
$
$ HISTORY EXPRESSIONS FOR SOLVER "Case1"
$
 history 'F_vs_d' expression {Crossplot("-Disp1","Force1")}

$
$ HISTORIES FROM FILES
$
 history 'FILE4' file "/home/prak1/LS-OPT/beispiele/parameter_identification/history_based/Test1.txt"
composites 1
$
$ COMPOSITE EXPRESSIONS
$
 composite 'MSE' {MeanSqErr(FILE4,F_vs_d)}
$
$ OBJECTIVE FUNCTIONS
$
 objectives 1
 objective 'MSE' 1
$
$ THERE ARE NO CONSTRAINTS!!!
$
 constraints 0
$
$ JOB INFO
$
 iterate param design 0.01
 iterate param objective 0.01
 iterate param stoppingtype or
 iterate 3
STOP

Results

Document Actions

Results

Opt History

Opt History

Optimization History

  1. For Type of Plot select Opt History.
  2. From Entity to Monitor select Composites → MSE.
  3. Click near the iteration number for information and curve comparison.
opthistory_mse11.png
  1. Shows the iteration number.
  2. View the entity values for the current iteration.
  3. Push the MeanSqErr curves button to view a comparison of the history in LS-PrePost.
opthistory_mse22.png
History Comparison between the cross plot F_vs_d (green line) and the imported file (red line) in LS-PrePost.compare_history1.png

Confidence Intervals

Confidence Intervals

90% Confidence Intervals

The confidence intervals for the two parameters YMod and Yield can be found in the lsopt_report file in the main directory.

→ YMod is rather insignificant and Yield is significant.

conf_interval1.png

Download

Download

The complete data set (input and command files) is available for download as tar.gz history_MSE.tar.gz or zip-file history_MSE.zip.