Ansys Advanced Analysis Techniques Guide.pdf

ANSYS Advanced

Analysis Techniques

Guide

ANSYS Release 9.0

002114

November 2004

ANSYS, Inc. is a

UL registered

ISO 9001: 2000

Company.

ANSYS Advanced Analysis Techniques

Guide

ANSYS Release 9.0

ANSYS, Inc.

Southpointe

275 Technology Drive

Canonsburg, PA 15317

ansysinfo@ansys.com

http://www.ansys.com

(T) 724-746-3304

(F) 724-514-9494

ANSYS, DesignSpace, CFX, DesignModeler, DesignXplorer, ANSYS Workbench environment, AI*Environment, CADOE and any and all ANSYS, Inc. product

names referenced on any media, manual or the like, are registered trademarks or trademarks of subsidiaries of ANSYS, Inc. located in the United States or

other countries. ICEM CFD is a trademark licensed by ANSYS, Inc. All other trademarks and registered trademarks are property of their respective owners.

ANSYS, Inc. is a UL registered ISO 9001: 2000 Company.

ANSYS Inc. products may contain U.S. Patent No. 6,055,541.

Microsoft, Windows, Windows 2000 and Windows XP are registered trademarks of Microsoft Corporation.

Inventor and Mechanical Desktop are registered trademarks of Autodesk, Inc.

SolidWorks is a registered trademark of SolidWorks Corporation.

Pro/ENGINEER is a registered trademark of Parametric Technology Corporation.

Unigraphics, Solid Edge and Parasolid are registered trademarks of Electronic Data Systems Corporation (EDS).

ACIS and ACIS Geometric Modeler are registered trademarks of Spatial Technology, Inc.

FLEXlm License Manager is a trademark of Macrovision Corporation.

This ANSYS, Inc. software product and program documentation is ANSYS Confidential Information and are furnished by ANSYS, Inc. under an ANSYS

software license agreement that contains provisions concerning non-disclosure, copying, length and nature of use, warranties, disclaimers and remedies,

and other provisions. The Program and Documentation may be used or copied only in accordance with the terms of that license agreement.

See the ANSYS, Inc. online documentation or the ANSYS, Inc. documentation CD for the complete Legal Notice.

If this is a copy of a document published by and reproduced with the permission of ANSYS, Inc., it might not reflect the organization or physical appearance

of the original. ANSYS, Inc. is not liable for any errors or omissions introduced by the copying process. Such errors are the responsibility of the party

providing the copy.

Table of Contents

1. Design Optimization ........................................................................................................................... 1–1

1.1. Design Optimization Terminology ................................................................................................. 1–1

1.2. Understanding GUI Paths and Command Syntax ........................................................................... 1–4

1.3. Employing Design Optimization .................................................................................................... 1–4

1.3.1. Create the Analysis File ......................................................................................................... 1–5

1.3.1.1. Build the Model Parametrically .................................................................................... 1–5

1.3.1.2. Obtain the Solution ..................................................................................................... 1–6

1.3.1.3. Retrieve Results Parametrically .................................................................................... 1–7

1.3.1.4. Preparing the Analysis File ........................................................................................... 1–7

1.3.2. Establish Parameters for Optimization .................................................................................. 1–8

1.3.3. Enter OPT and Specify the Analysis File ................................................................................. 1–8

1.3.4. Declare Optimization Variables ............................................................................................ 1–9

1.3.5. Choose Optimization Tool or Method .................................................................................. 1–9

1.3.6. Specify Optimization Looping Controls ............................................................................... 1–10

1.3.7. Initiate Optimization Analysis ............................................................................................. 1–11

1.3.8. Review Design Sets Data .................................................................................................... 1–12

1.3.8.1. Manipulating Designs Sets ......................................................................................... 1–13

1.4. Multiple Optimization Executions ................................................................................................ 1–14

1.4.1. Restarting an Optimization Analysis .................................................................................... 1–14

1.5. Optimization Techniques ............................................................................................................ 1–15

1.5.1. Subproblem Approximation Method .................................................................................. 1–15

1.5.1.1. Approximations ......................................................................................................... 1–15

1.5.1.2. Conversion to an Unconstrained Problem .................................................................. 1–15

1.5.1.3. Convergence Checking .............................................................................................. 1–16

1.5.1.4. Special Considerations for Subproblem Approximation .............................................. 1–16

1.5.2. First Order Method ............................................................................................................. 1–17

1.5.2.1. Convergence Checking .............................................................................................. 1–17

1.5.2.2. Special Considerations for the First Order Method ...................................................... 1–18

1.5.3. Random Design Generation ............................................................................................... 1–18

1.5.4. Using the Sweep Tool ......................................................................................................... 1–18

1.5.5. Using the Factorial Tool ...................................................................................................... 1–19

1.5.6. Using the Gradient Evaluation Tool ..................................................................................... 1–19

1.6. Guidelines on Choosing Optimization Variables ........................................................................... 1–20

1.6.1. Choosing Design Variables ................................................................................................. 1–20

1.6.2. Choosing State Variables .................................................................................................... 1–21

1.6.3. Choosing the Objective Function ........................................................................................ 1–22

1.7. Hints for Performing Design Optimization ................................................................................... 1–22

1.7.1. Generating the Analysis File ............................................................................................... 1–22

1.7.2. Fixing Design Variable Values After Execution ..................................................................... 1–23

1.7.3. Modifying the Optimization Variables After Execution ......................................................... 1–24

1.7.4. Local Versus Global Minimum ............................................................................................. 1–24

1.7.5. Minimum Weight Versus Minimum Volume ........................................................................ 1–24

1.7.6. Mesh Density ..................................................................................................................... 1–25

1.7.7. Using Substructures ........................................................................................................... 1–25

1.8. Sample Optimization Analysis ..................................................................................................... 1–25

1.8.1. Problem Description .......................................................................................................... 1–25

1.8.2. Problem Specifications ....................................................................................................... 1–25

1.8.3. Using a Batch File for the Analysis ....................................................................................... 1–25

1.8.4. Using the GUI for the Analysis ............................................................................................. 1–27

1.8.5. Where to Find Other Examples ........................................................................................... 1–30

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika: