Introduction to LS-OPT

Objective

This 3-½ day course is an introduction to the use of the optimization code LS-OPT for optimal design. An emphasis is placed on interfacing with LS-DYNA. Both basic theoretical concepts of optimization as well as practical aspects of optimal design are covered. The course includes workshop sessions in which the theoretical topics of the day will be applied.

Audience

This seminar is intended to enable engineers with basic knowledge of LS-DYNA to become more productive in design and parameter identification. An introductory class in LS-DYNA is therefore a prerequisite. Optimization knowledge is not required.

Notes

The instructor for this course is Dr. Nielen Stander. Lectures begin daily at 9:00 a.m. and run until 5:30 p.m., except for the last day when the course concludes at 12:00 p.m. The classroom machines are PCs running Linux (CA) or Windows (MI).

Contents

Over the duration of the class, students work in groups of two (sometimes individually) to work/solve the exercises. The exercises are simple, so that they take a short time to run, but contain enough complexity to give insight into the optimization process. Most of the problems are nonlinear (large deformation) dynamic and will be solved using LS-DYNA simulation. If time allows, new, more advanced features such as multidisciplinary design optimization will be demonstrated.

Section 1

  • Course Outline
  • Introduction to Design Optimization using industrial examples
  • LS-OPT features
  • Theory: Formulation
    • Optimality criteria
    • Gradient computation
    • Response Surface Methodology
    • Experimental Design
    • Design model adequacy checking
    • Successive approximations
    • Design scenarios

Section 2

  • Command Language
    • Command File structure
    • Program execution
    • Job Monitoring
    • Restarting
    • Database and output
    • Preparation and test procedure
    • Experimental design options
    • Response extraction
    • Response surface options
    • Simple design formulation

Section 3

  • LS-DYNA interface features
    • ASCII database
    • Binary database
    • Filtering
    • Time history functions
    • Injury criteria
    • Metal forming criteria: FLD, thickness
  • Interfacing a parametric preprocessor
  • Design formulation
    • Composite functions
    • Min-Max
  • Iterative design

Section 4

  • Trade-Off studies
  • Exercise problems
    • Polynomial optimization problems
    • Crashworthiness
    • Parameter Identification
    • Sheet metal forming
    • Other nonlinear examples