# Problem Description

The complete data set for this example is available for download as .tar.gz coupling_ANSA.tar.gz or as .zip coupling_ANSA.zip.

The example has been tested with ANSA 12.1.4. For newer versions of ANSA please refer to the tutorial 9-optimizing_with_LSOPT.pdf which is distributed with ANSA.

## Introduction

This example presents the coupling of LS-OPT with a pre-processor (ANSA). There are four steps needed to connect ANSA with LS-OPT:

• Model Definition
• morphing boxes
• morphing parameters
• parameters from ANSA Card entities
• design variables for morphing parameters
• design variables for ANSA parameters
• session commands
• design variables and FE output files
• µETA post set up
• response extraction
• LS-OPT setup
• design variables
• responses
• objective function
• constraints

In order to perform the first two steps the user should be familiar with the functionality of ANSA and the Morphing Tool.

### Problem Description

A front rail will be tested in crash simulation. The target is to find the best arrangement of its embosses in order to minimize the acceleration that appears in the test. As constraints are used the mass of the rail and the intrusion. These constraints must be kept within a specific range.

• Objective function: acceleration
• Constraints: intrusion, mass

### Design Variables

The design variables are:

• The depth of the embosses (-6=<Emboss_depth =<0)
• The width of the embosses (-2=<Emboss_width =<2)
• The distance between the embosses (-5=<Emboss_dist=<10)
• The thickness of the rail (Thickness={0.8, 0.9, 1.0, 1.1, 1.2, 1.4, 1.7})

### Nominal Run

A first run of the nominal case (the rail without the embosses) can give an estimation of the values of acceleration, mass and intrusion. All measurements took place at a reference point as shown at the picture on the right. Output results have been created for this position which are written in the d3thdt result file of LS-DYNA.

The values from the nominal run are:

• X acceleration: -0.448 mm/s2
• X coordinate: -314.8 mm
• Mass: 1.6 Kg
• Barrier Mass: 400.8 Kg
• Initial velocity: 8 m/s
• Rail thickness: 1.2 mm

The boundaries for the constraints are:

• Mass<1.8
• X_coordinate<-300

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