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LS-OPT

Solvers

Solvers

In this step the coupling of ANSA with the LS-OPT will be demonstrated. The presented functionality is available since ANSA 12.1.3 and LS-OPT 3.3. In order to skip the previous sections the user can use the rail_final.ansa file where the morphing actions and the Optimization Task are already defined. However there is the need to rename the file as rail.ansa.

→ Open LS-OPTui.

Define Pre-Processor and Solver

  1. Select the Solvers panel.
  2. As Pre-Processor select ANSA.
prepro1.png
  1. Browse for the Command that runs ANSA.
  2. Browse for the Input File  of the design variables: rail_DV.txt.
  3. Browse the Database rail.ansa for this example.
  4. Specify the LS-DYNA executable Command.
  5. Specify the input file: main.key with the include ansaout.
  6. For Name of Analysis Case, enter Case_1.
  7. Push the Add button.
The input file main.key.
*KEYWORD
*CONTROL_TERMINATION
$   ENDTIM    ENDCYC     DTMIN    ENDENG    ENDMAS
       60.         0        0.        0.        0.
*DATABASE_BINARY_D3PLOT
       1.                              
*INCLUDE
ansaout          
*END

Variables

Variables

Check Variables

  1. Select the Variables panel.

 

Note that the created variables are read in from the file rail_DV.txt.

variables1.png

Sampling

Sampling

Sampling

  1. Select the Sampling panel.
  2. Choose a Linear METAMODEL.
  3. Choose D-Optimal for the POINT SELECTION.
sampling1.png

Responses

Responses

Create the Response (Accel.)

  1. Select the Responses panel.
  2. Choose NODOUT from the list.
  3. Enter the ID 7710*.
  4. For Component select Acceleration.
  5. For Direction select X Component.
  6. From Select choose Maximum Value.
  7. Enter 0.0 in the From time field (this will choose the max. value of acceleration in x-direction during the crash).
  8. For Filtering choose SAE Filter.
  9. Enter 180.0 for Frequency.
  10. For Response Name enter  a label, e.g. acceleration.
  11. Push the Add button.
resp_accel1.png

Create the Response (Displ.)

  1. Choose NODOUT from the list.
  2. Enter the ID 7710*.
  3. For Component select Displacement.
  4. For Direction select X Component.
  5. For Response Name enter a label, e.g. displacement.
  6. Push the Add button.

 

* NOTE: 7710 is the ID of the reference node where acceleration and intrusion will be measured.

resp_disp1.png

Create the Response (Mass)

  1. Choose MASS from the list.
  2. Select the Attribute Mass.
  3. Enter 2 for List of Parts (PID of the body of the rail which will be included in the mass calculation.
  4. Push the Add button.
resp_mass1.png

Objective

Objective

Objective Function

  1. Select the Objective tab.
  2. From Response select acceleration as the objective.
  3. For Weight leave the default 1.
objective1.png

Constraints

Constraints

Constraints

  1. Select the Constraints panel.
  2. From Response select displacement as the constraint..
  3. For Upper Bound enter -300.
  4. From Response select mass as the constraint..
  5. For Upper Bound enter 1.8.
 		constraints1.png

 

Run

Run

Run the Optimization

  1. Select the Run panel.
  2. For Number of iterations enter 10.
  3. Push the Run button.
run1.png

 

Com-file

Com-file

The created command file may look like this:

"Optimization Problem"
$ Created on Tue Apr 29 10:59:44 2008
solvers 1
responses 3
$
$ NO HISTORIES ARE DEFINED
$
$
$ DESIGN VARIABLES
$
variables 4
 Variable 'Emboss_Depth' -1
  Lower bound variable 'Emboss_Depth' -6
  Upper bound variable 'Emboss_Depth' 0
 Variable 'Emboss_Width' 1
  Variable 'Emboss_Width' discrete {-2 -1 0 1 2 }
 Variable 'Emboss_Dist' 1
  Lower bound variable 'Emboss_Dist' -5
  Upper bound variable 'Emboss_Dist' 10
 Variable 'Thickness' 1.2
  Variable 'Thickness' discrete {0.8 0.9 1 1.2 1.4 1.7 }

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

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$      SOLVER "case_1"
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$
$ DEFINITION OF SOLVER "case_1"
$
 solver dyna960 'case_1'
  solver command "dyn971"
  solver input file "main.key"
  solver check output on 
  solver compress d3plot off 
$ ------ Pre-processor --------
  prepro ANSA
  prepro command "ansa.sh"
  prepro database file "rail_final.ansa"
  prepro input file "rail_DV.txt"
$ ------ Metamodeling ---------
  solver order linear
  solver experiment design dopt
$ ------ Job information ------
  solver concurrent jobs 1
$
$ RESPONSES FOR SOLVER "case_1"
$
 response 'acceleration' 1 0 "BinoutResponse -res_type Nodout  -cmp x_acceleration -id 7710 -select MIN -start_time 0.0000 -filter SAE  -filter_freq 180.000"
 response 'displacement' 1 0 "BinoutResponse -res_type Nodout  -cmp x_displacement -id 7710 -select MIN -start_time 0.0000 -filter SAE  -filter_freq 180.000"
 response 'mass' 1 0 "DynaMass 2 MASS"

$
$ OBJECTIVE FUNCTIONS
$
 objectives 1
 objective 'acceleration' 1
$
$ CONSTRAINT DEFINITIONS
$
 constraints 2
 constraint 'displacement'
  upper bound constraint 'displacement' -300
 constraint 'mass'
  upper bound constraint 'mass' 1.8
$
$ JOB INFO
$
 iterate param design 0.01
 iterate param objective 0.01
 iterate param stoppingtype or
 iterate 10
STOP

Download LS-OPT

Download LS-OPT

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