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DOCUMENT DOWNLOADED FROM GP TECHNOLOGIES INC. WEB SITE at http:// www.ghiocel-tech.com
ProCORFAProCORFAMain WindowMain WindowMain Menu Items:- File- Input Data- Component Model- Analysis Options- Review Results- Graphics- Setting- Help
ProCORFAProCORFA GUI: Main Window DialogGUI: Main Window Dialog
DOCUMENT DOWNLOADED FROM GP TECHNOLOGIES INC. WEB SITE at http:// www.ghiocel-tech.com
ProCORFAProCORFA Software Configuration LayoutSoftware Configuration LayoutPROCORFA
Analysis
Crack Initiation
Crack Propagation
ProCorfa Crack Growth Models
AFGROW Crack Growth Models
ProCorfa Input Database
Mechanical Properties
Constitutive Equations
Crack Initiation Model
Crack Propagation Model
Pitting Model
Material Properties
Crack Geometry
Load
Maintenance Data
Lap Joint FEA(ANSYS)
StochasticStress Field
Life Modeling Cost Modeling Net Section Modeling
Stochastic Crack Growth
Probability Of Failure
Availability
Planned Cost
Unplanned Cost
Availability Cost
PROCORFA
Analysis
Crack Initiation
Crack Propagation
ProCorfa Crack Growth Models
AFGROW Crack Growth Models
ProCorfa Input Database
Mechanical Properties
Constitutive Equations
Crack Initiation Model
Crack Propagation Model
Pitting Model
Material Properties
Crack Geometry
Load
Maintenance Data
Lap Joint FEA(ANSYS)
StochasticStress Field
Life Modeling Cost Modeling Net Section Modeling
Stochastic Crack Growth
Probability Of Failure
Availability
Planned Cost
Unplanned Cost
Availability Cost
DOCUMENT DOWNLOADED FROM GP TECHNOLOGIES INC. WEB SITE at http:// www.ghiocel-tech.com
ProCORFAProCORFAProbabilistic Life Probabilistic Life
ModuleModule
ProCORFAProCORFAManagement ModuleManagement Module
GUIGUI
ProCORFAProCORFARiskRisk--Based MaintenanceBased Maintenance
ModuleModuleProCORFAProCORFA--AFGROW AFGROW
Link ModuleLink Module
Component SFEA Component SFEA Stress/Strain Results Stress/Strain Results
ANSYS/Other codeANSYS/Other code
ProCORFAProCORFA Modular ConfigurationModular Configuration
DOCUMENT DOWNLOADED FROM GP TECHNOLOGIES INC. WEB SITE at http:// www.ghiocel-tech.com
MultiMulti--Scale Stochastic FE ApproachScale Stochastic FE Approach
Global Model:• Shell and beam elements• “Weld” stringers and frames with
skin panel• Linear analysis• Find critical locations
Local Model:• Solid elements• Includes contacts• Obtain BC from global model• Consider stochastic parameters• Detailed local stresses
Very Local Model:• Axi-symmetric elements• Material and full contact
nonlinearity • Residual stress and interference
analysis
Displacement constrains of boundary nodes are interpolated from global model using sub-modeling technique
(collaboration with STI Technologies Inc.)(collaboration with STI Technologies Inc.)
Single hole plate-rivet model
Contact FEAObtain local stress Obtain local stress σσ at at key locationskey locations
Fracture Mechanics Fracture Mechanics analysis is performed analysis is performed under same load under same load conditions to calculate the conditions to calculate the stress intensity stress intensity ∆∆K as K as function of crack lengthfunction of crack length
Dimension less stress intensity aKaπσ
β =)(
One-side crack
Two-side crack
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Stochastic FE Analysis for Local Stress DistributionStochastic FE Analysis for Local Stress Distribution
Location variation
Shape variations
Local corrosion or wear effects
Plate thickness varitions
Distance variations
Size variations
- Obtain the local stress distribution considering all the random variabilities.
- Perform fatigue analysis assuming the same dimensionless stress intensity βobtained from the single-hole model shown in the previous slide
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Original Image in color Corr1
Corrosion Sample # 1
Gray Scale Corr1
Original RGB Image
Stochastic Corrosion Surface TopographiesStochastic Corrosion Surface Topographies
Grayscale Image
Surface Plots from different Views
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Simulated Stochastic Corroded Surfaces for FE ModelSimulated Stochastic Corroded Surfaces for FE Model
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Constitutive ModelConstitutive ModelMechanical PropertiesMechanical Properties
Mechanical Properties & Constitutive Model Mechanical Properties & Constitutive Model
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Corrosion Pitting Corrosion Pitting
Strain Life and Damage Model Strain Life and Damage Model
Strain Life, Fatigue Damage Model and Pitting Strain Life, Fatigue Damage Model and Pitting
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Statistical Crack PopulationStatistical Crack PopulationVariable LoadingVariable Loading
Variable Loading and Statistical Crack Population Variable Loading and Statistical Crack Population
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Multiple InspectionsMultiple InspectionsNDI POD CurvesNDI POD Curves
Maintenance Info: POD Curves, Inspection Times Maintenance Info: POD Curves, Inspection Times
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Risk AnalysisRisk Analysis
Probabilistic Pit GrowthProbabilistic Pit Growth
Life Prediction and RiskLife Prediction and Risk--Based Condition Assessment Based Condition Assessment
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Crack Growth StatisticsCrack Growth StatisticsFailure Risk EvolutionFailure Risk Evolution
Crack Statistics & RiskCrack Statistics & Risk--Based Condition Assessment Based Condition Assessment
DOCUMENT DOWNLOADED FROM GP TECHNOLOGIES INC. WEB SITE at http:// www.ghiocel-tech.com
Probabilistic Optimal LifeProbabilistic Optimal Life--Cycle Cost AnalysisCycle Cost Analysis
Objective: Develop an optimal inspection program that minimizes cost under reliability constraints
Assumptions:
- Crack growth model:A(t)=A0 exp(Λt), t > 0 (A0 and Λ are random)
- Cracks with length. A(t) > acr => replaced (failure). ad < A(t) ≤ acr => repaired. A(t) ≤ ad => undetected
- System failure probability Pf (t) > pf,0 at all times
(collaboration with Professor M. Grigoriu, Cornell University)(collaboration with Professor M. Grigoriu, Cornell University)
DOCUMENT DOWNLOADED FROM GP TECHNOLOGIES INC. WEB SITE at http:// www.ghiocel-tech.com
Inspection and Maintenance Policy:
Model parameters: - Cost: ci, cr and cf = inspection, repair, failure costs- System life: τ > 0- Inspection schedule: (t1,…,tn) = inspection times
A 0 ( t 1 ) > a c r
A 0 ( t 1 )≤ a c r A 0 ( t 1 ) > a d
A 1 ( t 2 - t 1 ) > a c r
A 1 ( t 2 - t 1 )≤ a c r
A 0 ( t 2 ) > a c r
A 0 ( t 1 )≤ a d
A 0 ( t 1 )≤ a c r
A 2 ( τ - t 2 ) > a c r
A 2 ( τ - t 2 )≤ a c r A 1 ( t 2 - t 1 ) > a d
A 1 ( t 2 - t 1 )≤ a d A 1 ( τ - t 1 ) > a c r
A 1 ( τ - t 1 )≤ a c r
A 3 ( τ - t 2 ) > a c r
A 3 ( τ - t 2 )≤ a c r
A 0 ( τ ) > a c r
A 0 ( τ )≤ a c r
A 0 ( t 2 ) > a d
A 0 ( t 2 )≤ a c r
t im e 0 t 1 t 2 τ
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Total Cost and Failure Probabilities:
- Total cost at t = τ:
- Failure probabilities:
} samples { # }a)t(A{ # )t(P̂ cr
f
>=
time
)(tP̂f
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Optimization algorithm:
- Problem statement:
- Feasible region for n=2:
feasible region
t1
t2
topt
)*ctat cost aly that totprobabilit )t,...,t*;c(q (where
t ... tt0 and p)(P ,p)t(P, ... ,p)t(P ,p(0)P
under )}t,...,t*;c(q{min
n1n
n21
0,ff0,fnf0,f1f0,ff
n1nnt,...,1t
>τ==τ≤≤≤≤≤
≤τ≤≤≤
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