PowerPointPrsentation

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KBE-System and Case-Library for
UG-Structures EUUG Usermeeting 2003 Peter Binde
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Content
- Dr. Wallner Group - Motivation for a new
Assistant System - Case Study
Automotive-Generator - Feature-Processing -
Concepts of the CBE-Assistant
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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
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Dr. Wallner Group - The Founders 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.
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Motivation for a new Assistant System
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Present Situation
More and more FEA becomes the designers daily work
VDI Report about Adam Opel Project - Designers
do FEA themselves -
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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
?
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Solution - Store all knowledge anyone has
learned in past-cases. - Reuse that knowledge
Very similar to human learning
Method - Case Based Reasoning (CBR)
Superior to application of rules
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All we need is - Two new buttons in our
UG-Scenario system
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Questions - How to store a solution? - How to
adapt knowledge from a similar solution? - How
to find the most similar cases?
Find
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
Adapt
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Case Study Automotive Generator
Analysis Goals Find Characteristics, that
Contain Knowledge Develop a Structure for that
Knowledge
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Centrifugal-Analysis of Fan Characteristics,
that Contain Knowledge
Load-type Rotation
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Generator-Axle under Bending-Load
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Acceleration-Analysis of Housing
Forces, that result from contacting parts
Load-type Acceleration Geometry applied to
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Description of the Situation and Analysis-Task
by Computable Elements
Effect Acceleration
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Project
Structure for Storage of a Task
Analysis-scenario
Part
Material
Property-aggregation...
Form-feature
Contact
Form-feature
Part
Form-feature
Fix
Load-Effects
Solution-Group
Property-aggregation...
Form-feature
Part
Material
Analysis-scenario
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Description of a Solution by Computable
Elements
A solution contains idealization-methods and the
result

• Idealization of screw-connections
• Neglected pre-load
• Rigid Type,

• Idealization of face-coupling
• Restriction of DOFs

• Mesh-property in critical area
• Number, quality, type of elements

• Idealization of acceleration
• To be neglected

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

• Idealization of adjoining parts
• Acceleration-Force on contacting faces

• Geometry-Idealization
• Small feature removal

• Idealization of material
• Isotropic, linear

Solver-Parameter
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Feature-Processing
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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.
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Knowledge Management using Semantics and Features
We try to build up models only by use of
features This method automatically captures our
knowledge and provides standard-solutions
CAD Features (1) Sketch (2) Revolved (3)
Pocket (4) Pocket (5) Hole (6) Threads
FEM Features Fixed Face Centrifugal
Load Concentrated Mass Stress Calculation Fatigue
Calculation
rot
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Feature-Processing Simple Example
?
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Which feature-description of a hole is preferred
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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.
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Concepts of the CBE-Assistant
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Feature Recognition
Extracts and classifies all available
feature-information to an extended
feature-navigator
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Transparency
Example Part-connections are shown completely
Fan is connected to Rotator. The involved
form-features as well as contact properties
are shown.
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Feature-Attributes
Properties of features can be edited
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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.
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Tasks / Solutions are Separated
CBE feature-information merely includes task
(situation) -descriptions Corresponding solutions
are given in the found cases Problem-Descriptio
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Search for non-linear contact
Search for contacting parts, that can separate
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Storage of Successful Solved Cases
The feature-Information is stored in a xml
database
CAD/FEM-System
Analysis Case
CBE-System
prt
xml
Case Libary
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Definition of a Problem Two Possibilities
1. Build up features in the CAD/FEM-system
1. Build up features in the CBE-system
AdvantageThis method can be used with any
CAD/FEM-system
AdvantageAll existing features are used
automatically
2. Start CBE-system3. Optional insert
further knowledge4. Start search
2. Start search
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Similarity-Measurements Method A Find Similar
Features Incremental ranking of a requested
feature-class based on a user-weighted
Manhattan-Distance
ExampleRequested feature-class Partn10
Attributes Weights
ExampleNumber of requested results 6
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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
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Example
Stress-analysis on a sheet-metal-bead
Task-pattern
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