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Slide 1
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. Chapter 4 Robust
Design 9.0
Slide 2
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-2 9.0 New Features Background of Robust Design
What is Robust Design, DFSS, ? Design for Quality Robust Design in
Engineering Analysis Illustration Example Sources of Uncertainty
Effects of Uncertainty Compare Deterministic and Probabilistic
Approach Enabling Technologies Demonstration Overview of
Application Example Demo Questions Robust Design Overview
Slide 3
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-3 9.0 New Features Background of Robust Design
What is Robust Design, DFSS, etc.? Uncertainty Analysis Quantify
the effect of uncertainties on the performance of a product (mean
value, standard deviation, etc.) Reliability Analysis Quantify the
reliability (failure probability, defects per million) Robust
Design or Design For Six Sigma (DFSS) Optimize the design such that
it is insensitive to unavoidable uncertainties (e.g.
material,loads,) Reliability-based Optimization Optimize the design
such that reliability is maximized or failure probability (defects
per million) is minimized Robust Design is often synonymous to
Design for Six Sigma or Reliability-based Optimization
Slide 4
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-4 9.0 New Features Background of Robust Design
Design for Quality Six Sigma Quality = Only 3.4 out of 1000000
parts fail Six Sigma Quality is inherently a probabilistic
statement LSL = Lower Specification Limit USL = Upper Specification
Limit P.S.: Gaussian distribution is not realistic, but does convey
the idea correctly
Slide 5
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-5 9.0 New Features Background of Robust Design
Design for Quality quality Six Sigma = Optimize manufacturing
processes such that they automatically produce parts conforming
with six sigma quality qualityquality Design For Six Sigma =
Optimize the design such that the parts conform with six sigma
quality, i.e. quality and reliability are explicit optimization
goals Design for Six Sigma: Achieve Designed-In quality as opposed
to letting customers find out about quality problems Make informed
decision that are critical to quality early in the development
process
Slide 6
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-6 9.0 New Features FROM: Reactive Quality
Management Extensive Design Rework Assess Performance by
build-test-build-test- Fix performance/quality problems after
manufacturing Quality is Tested-In TO: Predictive Quality
Management Controlled Design Parameters Estimate likelihood/rate of
performance problems in design & development Address quality
problems in design & development Designed for robust
performance and quality Quality is Designed-In Background of Robust
Design Design for Quality Robust Design is a Paradigm Shift
Slide 7
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-7 9.0 New Features Purpose of Robust Design
InputInput ANSYSANSYS OutputOutput Material Properties Geometry
Boundary Conditions Deformation Stresses / Strains Fatigue,
Creep,... Its a reality that input parameters are subjected to
scatter => automatically the output parameters are uncertain as
well!! Background of Robust Design Robust Design in Engineering
Analysis
Slide 8
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-8 9.0 New Features Questions answered with
Robust Design: How large is the scatter of the output parameters?
What is the probability that output parameters do not fulfill
design criteria (failure probability defects per million)? How much
does the scatter of the input parameters contribute to the scatter
of the output (sensitivities critical-to-quality)? Background of
Robust Design Robust Design in Engineering
AnalysisANSYSDesignXplorerANSYSDesignXplorer Purpose of Robust
Design
Slide 9
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-9 9.0 New Features PropertySD/Mean % Metallic
materiales, yield15 Carbon fiber composites, rupture17 Metallic
shells, buckling strength14 Junction by screws, rivet, welding8
Bond insert, axial load12 Honeycomb, tension16 Honeycomb, shear,
compression10 Honeycomb, face wrinkling8 Launch vehicle, thrust5
Transient loads50 Thermal loads7.5 Deployment shock10 Acoustic
loads40 Vibration loads20 Source: Klein, Schueller et.al.
Probabilistic Approach to Structural Factors of Safety in
Aerospace. Proc. CNES Spacecraft Structures and Mechanical Testing
Conf., Paris 1994 Background of Robust Design Sources of
Uncertainty
Slide 10
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-10 9.0 New Features CFD FEMCAD FEM Geometry
Materials, Bound.- Cond., Loads,... Materials, Bound.- Cond.,...
Materials, Bound.- Cond., Loads,... LCF Materials 0.1-10% 5-50%
5-100% 30-60% ??% 5-100% Thermal Analysis Structural Analysis
Background of Robust Design Effects of Uncertainty
Slide 11
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-11 9.0 New Features Influence of Youngs Modulus
and Thermal Expansion Coefficient on thermal stresses: thermal = E
T Deterministic Approach: Mean = E Mean Mean T Mean = typically
used results Probabilistic Approach: Probability that ( thermal
>= 105% Mean ) ( thermal >= 110% Mean ) E scatters 5% 16% (~1
out of 6) 2.3% (~1 out of 40) E and scatter 5% 25% (~1 out of 4) 8%
(~1 out of 12) E, & T scatter 5% 28% (~1 out of 4) 13% (~1 out
of 8) Background of Robust Design Effects of Uncertainty
Slide 12
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-12 9.0 New Features Turbine What-If Analysis
Series Background of Robust Design Compare
Deterministic/Probabilistic
Slide 13
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-13 9.0 New Features Background of Robust Design
Enabling Technology: Parameterization Robust Design for all
parameters including CAD
Slide 14
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-14 9.0 New Features Background of Robust Design
Enabling Technology: Parameterization Robust Design Supports APDL
Parameters
Slide 15
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-15 9.0 New Features Background of Robust Design
Enabling Technology: Parameterization Robust Design Supports
ParaMesh Parameters ParaMesh for Geometric Type of Parameterization
For Legacy Models or Models with Signifiant FEA Abstraction such
that CAD update is problematic Example Ansys Input File: ! File
inp_parabatch.inp value=0
/syp,parabatch.exe,'testpb.rsx','testpb.cdb','location',%value%,'testpb_mod.cdb'
/inp,testpb_mod,cdb ! Input the modified geometry /solu Solve!
Solve it fini /post1 set,first *get,ndepright,node,232,u,z ! Get
results *get,ndepleft,node,2,u,z depdiff=ndepleft-ndepright fini
Paramesh dbInitial mesh Parameter name Parameter value Output mesh
Import Output mesh
Slide 16
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-16 9.0 New Features Background of Robust Design
Enabling Technology: DesignXplorer DesignXplorer manages the
parameters and the uncertainties
Slide 17
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-17 9.0 New Features CAD GeometryFEM Mesh FEM
Boundary Conditions Robust Design Demonstration Overview of
Application Example
Slide 18
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-18 9.0 New Features Results for Maximum
Principal Stress Pressure SideSuction Side Peak Value s Tang.
Leaning Axial Leaning Dove Tail Width Material Density (Gaussian)
Fillet Radius (Lognormal) Mass Design Variables and Uncertainties
Imbalance: ( p s ) 2 Avg.Stress: 0.5( p + s ) Peak Value p Robust
Design Demonstration Overview of Application Example
Slide 19
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-19 9.0 New Features Robust Design Demonstration
Robust Design Demonstration Demonstration
Slide 20
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. DesignXplorer Family
9.0
Slide 21
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-21 9.0 New Features DX Family 9.0 New Features
DesignXplorer Family (DesignXplorer and DesignXplorer VT) GUI
Structure Robust Design - Parameterize DFSS Results New Robust
Design View Optimize DFSS Results New Trade-Off Study Genetic
Algorithm for Sample Generation Variational Technology
(DesignXplorer VT) Support of Discrete Variables in Workbench RSX
File Viewing Additional Contact Support 2D Analysis
Slide 22
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-22 9.0 New Features DX Family 9.0 New Features
GUI Structure DFSS Charts Page Measures of robustness CDF Plot
Y-Axis can be scaled as Gaussian, Log-Normal, Weibull,
Exponential
Slide 23
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-23 9.0 New Features Separate DFSS Table Page
Statistics Available Customize Tables (add, delete) Sigma-Level in
Tables DX Family 9.0 New Features GUI Structure
Slide 24
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-24 9.0 New Features New Robust Design View New
DFSS Parameters showing up in Parameter View DX Family 9.0 New
Features Parameterize DFSS Results
Slide 25
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-25 9.0 New Features DX Family 9.0 New Features
Optimize DFSS results 1) 2) 2) Design Variables: Useable for Robust
Design Optimization 1) Random Variables: Uncontrollable used to
obtain DFSS results
Slide 26
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-26 9.0 New Features Same optimization
functionality as for GDS DX Family 9.0 New Features Optimize DFSS
results
Slide 27
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-27 9.0 New Features DX Family 9.0 New Features
Trade-Off Studies Mouse-Over Results Pareto Front for Conflicting
Goals, Tradeoffs Occur Here Both 2D and 3D Tradeoff Plots are
available
Slide 28
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-28 9.0 New Features Mouse- Over Results Pareto
Front for Conflicting Goals Infeasible Points in Pareto Front
InfeasibleFeasible DX Family 9.0 New Features Trade-Off
Studies
Slide 29
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-29 9.0 New Features Choice of Basic
(Screening), which is pseudo-random sampling method typically done
first, or Advanced (Genetic) Algorithm which is typically done
second DX Family 9.0 New Features Genetic Algorithm Sample
Generation
Slide 30
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-30 9.0 New Features Advanced sample options DX
Family 9.0 New Features Genetic Algorithm Sample Generation
Slide 31
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-31 9.0 New Features Advanced Sample Screening
Sample DX Family 9.0 New Features Genetic Algorithm Sample
Generation
Slide 32
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-32 9.0 New Features Variational Technology is
much faster than DOE for discrete parameters DesignXplorer VT 9.0
Support of Discrete Variables in Workbench
Slide 33
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-33 9.0 New Features Efficient multi- objective
Boolean optimizer based on Bayesian sampling faster optimization of
discrete parameters Boolean scatter chart representing the solution
points of all the parameter combinations of the selected
parameters. DesignXplorer VT 9.0 Support of Discrete Variables in
Workbench
Slide 34
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-34 9.0 New Features Allows user to view
Variational Technology results from a variety of sources including
DesignXplorer VT (of course) ANSYS using VT ParaMesh 3 rd Party
Variational Technology Applications DesignXplorer VT 9.0 RSX File
Viewing Hoover model solved with VT with the ANSYS Environment
Slide 35
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-35 9.0 New Features DesignXplorer VT 9.0
Support for Face-to-Edge Contact
Slide 36
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-36 9.0 New Features DesignXplorer VT 9.0
Support for Edge-to-Edge Contact
Slide 37
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-37 9.0 New Features DesignXplorer VT 9.0 2D
Analysis Allows Variational Technology analysis of 2D Simulation
studies to include: Axisymmetric Plane Strain Plane Stress
Slide 38
ANSYS, Inc. Proprietary 2004 ANSYS, Inc. October 1, 2004
Inventory #002156 4-38 9.0 New Features DesignXplorer and
DesignXplorer VT Thank you! Questions? Additional Questions: Ray
Browell (724) 514-3070 [email protected] Additional
Information: http://www.ansys.com/