dipl.-ing. peter binde kbe-system and case-library for ug-structures euug usermeeting 2003 peter...

Dipl.-Ing. Peter Binde

KBE-System and Case-Library for UG-Structures

EUUG Usermeeting 2003

Peter Binde

CaseBasedEngineering


Content

- Dr. Wallner Group

- Motivation for a new Assistant System

- Case Study: Automotive-Generator

- Feature-Processing

- Concepts of the CBE-Assistant


Dr. Wallner Group

Service around CAD, CAE, PDM

Focus on EDS-PLM Products

Competences:

- Process-analyses and -syntheses- Trainings and workshops- User-support and hotline- Integration-solutions and

software-development


Dr. Wallner Group:- Simulation

Focus on Design-Embedded Product-Simulation

Training, Consulting,Support for CAE

Projects shared by Industry & Research

Software for Knowledge-Processing



Dr. Wallner Group:- The Founder‘s Vision

Jens Wallner died this year by a car accident

His vision: - High Quality Service, for CAD/CAE/PDM –

will continue in the four Wallner-companies,that belong to the Group.


Motivation for a new Assistant System


Present Situation

More and more FEA becomes the designers daily work

VDI Report about Adam Opel Project: - Designers do FEA themselves -

=71N/mm2

u=0,4mm

= 72N/mm2

u=0,8mm

Scenario Original

Scenario Bördelung

Scenario Bead

=80N/mm2

u=0,9mmOriginal

Vergleich


Deficits

- Often special-knowledge is necessary

- Different methods for same problems are used

- Knowledge stays in the heads of specialists and key users

- Examples and summarised methods are only static

- Databases organize data, but do not know about the content

?


Solution:

- Store all knowledge anyone has learned in past-cases.- Reuse that knowledge

Retrieval of most appropriate cases

Adapting knowledge to a new Solution

Storageof a new solution

Case Base

Method:

- Case Based Reasoning (CBR)

Very similar to human learning

Superior to application of rules


All we need is:

- Two new buttons in our UG-Scenario system:


Questions:

- How to store a solution?

- How to adapt knowledge from a similar solution?

- How to find the most similar cases?

Find

Adapt

Store

Case Base

Answers:

- Extensively use feature-processing

- Store the feature-structure of successfully solved cases

- Find similar cases by pattern recognition of feature-structures

- Let the user interpret and adapt knowledge


Case Study: Automotive Generator Analysis

Goals: Find Characteristics, that Contain Knowledge Develop a Structure for that Knowledge


Centrifugal-Analysis of Fan:Characteristics, that Contain Knowledge

Design-context

Part for analysis & part-propertiesLoad-type: Rotation

Form-feature at result: Cutout,

Blended

Result-type: Stress & validation

Mesh-property at result,

Geometry-preparation

Solver-ParameterContact-Condition


Generator-Axle under Bending-Load

Design-context

Form-feature at result

Result-type: & ValidationPart for analysis &

part-properties

Support-Condition

Mesh-property at result

Solver-Parameter

Contact-Condition


Acceleration-Analysis of Housing

Design-context

Part for analysis & part-properties

Load-type: Acceleration& Geometry applied to

Forces, that result from contacting parts Form-feature at

result: BlendedResult-type: Stress & validation

Mesh-property at result

Solver-Parameter


Description of the Situation and Analysis-Task by Computable Elements

Effect: Acceleration

Adjoining Parts

- Form-feature

- Form-feature

…

…

- Form-feature

- Form-feature

Analysis-part

- Form-feature

- Form-feature

…

…

- Form-feature

- Form-feature

Adjoining Parts

- Form-feature

- Form-feature

…

Stress-Validation (requested)Contact

Screw (4x)

Face-FaceCoupling

Contact

Contact

Screw (4x)


Structure for Storage of a TaskProject

Analysis-scenario

Analysis-scenario

Part

Material

Form-feature

Contact

Solution-Group

Load-Effects

Part

Form-feature Part

Form-feature

Material

Property-aggregation...

Form-feature Fix

Property-aggregation...


Description of a Solution by Computable Elements

A solution contains idealization-methods and the result

Idealization of face-coupling

•Restriction of DOFs

Idealization of adjoining parts

•Acceleration-Force on contacting faces

Mesh-property in critical area

•Number, quality, type of elementsIdealization of acceleration

•To be neglected

Idealization of screw-connections

•Neglected pre-load

•Rigid Type, …

Idealization of material

•Isotropic, linear

Geometry-Idealization

•Small feature removal

Solver-Parameter

Result: -location, -type, -validation and -consequence


Feature-Processing


Features Model Design Characteristics

A Feature is a Container for a Design Characteristic

Example Feature Weld point:included information:

- Group of involved elements- Connectivity to geometry- Strength requirements- Tolerances- Costs- Manufacturing processes ...

Advantage: Weld point can be processed as a „weld point“.


Knowledge Management using Semantics and Features

We try to build up models only by use of featuresThis method automatically captures our knowledgeand provides standard-solutions

CAD Features:

(1) Sketch(2) Revolved(3) Pocket(4) Pocket(5) Hole(6) Threads

FEM Features:

Fixed FaceCentrifugal LoadConcentrated Mass

Stress CalculationFatigue Calculation

rot


Feature-Processing: Simple Example

Which feature-description of a hole is preferred

This,Because the hole can be recognizedautomatically by all following processes

? ?


Extensive Usage of Feature-Processing

-The user builds a clear, short feature-structure

-The user inserts further knowledge by assigning names, groups, descriptions, comments, … .

Insert as much knowledge as possible to the model.

Manually definition of features is also possible.

Knowledge is captured automatically

Knowledge is captured manually


Concepts of the CBE-Assistant



Feature Recognition

Extracts and classifies all available feature-information to an extended feature-navigator:


Transparency

Example: Part-connections are shown completely:

“Fan” is connected to “Rotator”.

The involved form-features as well as contact properties are shown.


Feature-Attributes

Properties of features can be edited


Manual Feature Definition

Features, not supported by UG-scenario can be added:

Stress-Results are validated on a Blend Form-Feature of the “Fan”.This feature is “extra” inserted by the user.


Tasks / Solutions are Separated

CBE feature-information merely includes task (situation) -descriptions

Corresponding solutions are given in the found cases

Problem-Description:

Search for non-linear

contact

Search for contacting parts, that can separate

Meets the “designers language”


Storage of Successful Solved Cases

The feature-Information is stored in a xml database

AnalysisCase

Case Libary

CBE-System

prt xml

CAD/FEM-System


Definition of a Problem: Two Possibilities

Advantage:All existing features are

used automatically

1. Build up features in the CAD/FEM-system

2. Start CBE-system3. Optional insert further knowledge4. Start search

1. Build up features in the CBE-system

2. Start search

Advantage:This method can be used

with any CAD/FEM-system


Similarity-Measurements:Method A: Find “Similar Features”

Incremental ranking of a requested feature-class based on a user-weighted “Manhattan-Distance”:

n

iii qpqpsim

1

),(

Example:Requested feature-class: Partn=10 Attributes + Weights

Example:Number of requested results: 6


Similarity-Measurements:Method B: Find “Similar Feature-Structures”

Exact sub-graph matching algorithm

Developed by: Dennis Shasha, Courant Institute,New York University &Rosalba Giugno, Math & Computer Science, University Catania


Example

P

Task-pattern:

A

Test-pattern:

Stress-analysis on a sheet-metal-bead

containedIn(P,A) = true

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