Strategy

Select the Strategy panel.
Switch the radio button of the section “Strategy for Metamodel-based Optimization” to "Sequential with Domain Reduction (SRSM)".
Select for Tolerance required for termination Design OR Objective.

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

Select the Solvers panel.
As Pre-Processor select ANSA.

Browse for the Command that runs ANSA.
Browse for the Input File of the design variables: rail_DV.txt.
Browse the Database rail.ansa for this example.
Specify the LS-DYNA executable Command.
Specify the input file: main.key with the include ansaout.
For Name of Analysis Case, enter Case_1.
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

Check Variables

Select the Variables panel.

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

Sampling

Select the Sampling panel.
Choose a Polynomial METAMODEL.
Set the Order to Linear.
Choose D-Optimal for the POINT SELECTION.

Responses

Create the Response (Accel.)

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

Create the Response (Displ.)

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

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

Create the Response (Mass)

Choose MASS from the list.
Enter 2 for List of Parts (PID of the body of the rail which will be included in the mass calculation.
Select the Attribute Mass.
For Response Name enter a label, e.g. mass.
Push the Add button.

Objective

Objective Function

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

Constraints

Select the Constraints panel.
From Response select displacement as the constraint..
For Upper Bound enter -300.
From Response select mass as the constraint..
For Upper Bound enter 1.8.

Run

Run the Optimization

Select the Run panel.
For Number of iterations enter 10.
Push the Run button.

Com-file

The created command file may look like this:

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
Command file "com.ansa"
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
$ Generated using LS-OPT Version 4.1
$
"Optimization Problem"
$
$ Created on Mon Mar 21 14:37:02 2011
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 "ls971_R4_2"
  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.ansa"
  prepro input file "rail_DV.txt"
$ ------ Post-processor --------
$   NO POSTPROCESSOR SPECIFIED
$ ------ 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 MAX -start_time 0.0000 -filter SAE  -filter_freq 180.0"
 response 'displacement' 1 0 "BinoutResponse -res_type Nodout  -cmp x_displacement -id 7710 
  -select TIME "
 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
$
$ PARAMETERS FOR METAMODEL OPTIMIZATION
$
 Metamodel Optimization Strategy DOMAINREDUCTION
$
  iterate param design 0.01
  iterate param objective 0.01
  iterate param stoppingtype or
$
$ OPTIMIZATION ALGORITHM
$
 Optimization Algorithm hybrid simulated annealing
  Use GSA
$
$ JOB INFO
$
 iterate 10
STOP

Sections

Personal tools

LS-OPT

Strategy

Strategy

Solvers

Solvers

Define Pre-Processor and Solver

Variables

Variables

Check Variables

Sampling

Sampling

Sampling

Responses

Responses

Create the Response (Accel.)

Create the Response (Displ.)

Create the Response (Mass)

Objective

Objective

Objective Function

Constraints

Constraints

Constraints

Run

Run

Run the Optimization

Com-file

Com-file

Download LS-OPT

Download LS-OPT