durability and fatigue life analysis using msc.fatigue

PAT318, Section 0, March 2002 S0-1

MSC.Software Corporation2 MacArthur Place

Santa Ana, CA 92707, USATel: (714) 540-8900Fax: (714) 784-4056

Web: http://www.mscsoftware.com

United StatesMSC.Patran SupportTel: 1-800-732-7284Fax: (714) 979-2990

Tokyo, JapanTel: 81-3-3505-0266Fax: 81-3-3505-0914

Munich, GermanyTel: (+49)-89-43 19 87 0Fax: (+49)-89-43 61 716

Durability and Fatigue LifeAnalysis Using MSC.Fatigue

March 2002

PAT318 Course Notes

P/N P3*V2002*Z*Z*Z*SM-PAT318-NT1


DISCLAIMER

MSC.Software Corporation reserves the right to make changes in specifications and other information contained in thisdocument without prior notice.The concepts, methods, and examples presented in this text are for illustrative and educational purposes only, and are notintended to be exhaustive or to apply to any particular engineering problem or design. MSC.Software Corporation assumesno liability or responsibility to any person or company for direct or indirect damages resulting from the use of anyinformation contained herein.User Documentation: Copyright 2001 MSC.Software Corporation. Printed in U.S.A. All Rights Reserved.This notice shall be marked on any reproduction of this documentation, in whole or in part. Any reproduction or distributionof this document, in whole or in part, without the prior written consent of MSC.Software Corporation is prohibited.MSC and MSC. are registered trademarks and service marks of MSC.Software Corporation. NASTRAN is a registeredtrademark of the National Aeronautics and Space Administration. MSC.Nastran is an enhanced proprietary versiondeveloped and maintained by MSC.Software Corporation. MSC.Marc, MSC.Marc Mentat, MSC.Dytran, MSC.Patran,MSC.Fatigue, MSC.Laminate Modeler, and MSC.MVision are all trademarks of MSC.Software Corporation.All other trademarks are the property of their respective owners.

PAT318 Course Director:[email protected]


TABLE OF CONTENTS

Section Page

1.0 Overview of Durability and Fatigue LifeCompany Overview .. 1-3Course Schedule . 1-9MSC.Fatigue Features . 1-10MSC.Fatigue User Interface 1-11Computer Aided Engineering Solutions 1-12Durability Management .. 1-13What is Durability .. 1-15What Drives Durability Management . 1-18Traditional Approach without CAE: Build it, Test it, Fix it . 1-21Add CAE: Analyze and Optimize . 1-22Predicting Product Life 1 Build and Use . 1-23Predicting Product Life 2 Add Sign-off Testing 1-24Predicting Product Life 3 Add Simulation Testing 1-25Predicting Product Life 4 Add CAE 1-26Integrated Durability Management Activities . 1-27Integration 1-28Design Approaches .. 1-29History of Fatigue Early Days 1-30A Short History of Fatigue -1 .. 1-31A Short History of Fatigue -2 1-34A Short History of Fatigue -3 .. 1-37A Short History of Fatigue -4 .. 1-39Fatigue Life Calculation Methods . 1-40S-N Method Similitude 1-42Crack Initiation (Strain Life) Method Similitude . 1-43Crack Propagation Method Similitude .. 1-44Fatigue Failure and Training ... 1-45


TABLE OF CONTENTS

Section Page

1.0 Overview of Durability and Fatigue LifeThe Physical Basis for Fatigue 1-46Slip and Stage I Growth 1-47Initiation and Propagation .. 1-48Use of Fatigue Technology . 1-50Fatigue Calculations in .. 1-51Who does what Fatigue Calculations 1-52Design against Fatigue .. 1-53Exploiting Fatigue Analysis the 5 box trick .. 1-55Durability Tools for Analysis and Test 1-57Integrated Approach to Durability . 1-58How Testing supports Analysis 1-59How Analysis supports Testing 1-60

2.0 Overview of MSC.FatigueWhats in MSC.Fatigue .... 2.3Life Prediction Process 2-5Elastic Stress or Strain Prediction Methods . 2-7Transient Dynamic Case 2.16Frequency Domain . 2.17Vibration Fatigue Methods .. 2.18FE Mesh Considerations . 2.19MSC.Fatigue Analysis Process .. 2.20MSC.Fatigue Main Form ..2.21Geometry/Stress Strain Results 2.24Materials Database Manager .. 2.26Loading Time History Database Manager .2.29Stress Life Analysis (S-N) .. 2.32Crack Initiation Analysis (E-N) 2.33


TABLE OF CONTENTS (cont.)

Section Page

2.0 Overview of MSC.FatigueCrack Growth Analysis (LEFM) .. 2.34Post-Processing: Results .2.36Post-Processing: design Optimization .. 2.39Advanced Features: MSC.Fatigue Spot weld .. 2.41MSC.Fatigue Software Strain Gauge 2.47MSC.Fatigue Utilities 2.52MSC.Fatigue Vibration . 2.54Multiaxial Fatigue .. 2.59

3.0 MSC.Fatigue User InterfaceThe Five Box Fatigue Analysis Trick 3.3Overview of MSC.Fatigue Analysis Process 3.4Running an FEA using MSC.Patran .. 3.5Or Import the model and results . 3.6MSC.Fatigue Main Form ..3.7Loading Information Form 3.8Material Information Form .. 3.9Solution Parameters Form .. 3.10MSC.Fatigue Files 3.11Job Control Form .. 3.13Results Form ..3.14Graphical Display of Fatigue Results .3.15



Section Page

4.0 Overview of PatranBuilding a model using Patran .. 4.3Step 1 - Analysis Preferences 4.4Step 2 - Import/Build Geometry .. 4.6Step 3 Creating an Analysis Model .4.7Step 4 Perform the Analysis .4.12Step 5 Evaluate Results 4.13Customization 4.15Starting MSC.Patran 4.16MSC.PATRAN File Option . 4.17MSC.Patran Files . 4.18The Main Form . 4.19Typical Widgets used in MSC.Patran 4.21System Icons . 4.22Entity Picking . 4.24Viewing/Model Manipulation 4.29List Processor 4.30Entity ID Syntax 4.31MSC.Patran Standards 4.32Online Help 4.33



Section Page

5.0 Geometry ModelingTopological Structures 5.3Geometry Building Blocks 5.4Importing, Exporting Geometry and FEM . 5.12MSC.Patran Database Access .. 5.17File Export Options .. 5.21Geometry Construction 5.24Geometry Form Anatomy 5.25Select Menu .. 5.26Geometry Entities Point 5.27Geometry Entities Curve . 5.33Geometry Entities Surface .. 5.44Geometry Entities Solid 5.59Solid Geometry Boolean . 5.66Geometric Entities Coordinate frame . 5.67

6.0 MeshingFinite Element . 6.3Introduction to Finite Element Meshing 6.5MSC.Patran Meshing Algorithms . 6.6Iso (Mapped) Mesher) 6.7Paver (Free) Mesher for Surfaces 6.10Iso (Mapped) Mesh Vs. Paver (Free) Mesh 6.12Meshing Control using Mesh Seeds 6.16Tetrahedral Mesher TET Mesh . 6.17Sweep Mesher . 6.19Association of Finite Elements to Geometry 6.21Finite Element Form 6.22



Section Page

6.0 MeshingWhere to Start with Meshing .. 6.23Mesh Seeding .. 6.24Meshing Parametric Solids . 6.28Tetmeshing Solids 6.29Tetmeshing from 2D Elements surrounding Volume .. 6.31FEM Creation Tool Transform 6.32Sweep Meshing 6.33FEM Creation Tool Element/Edit .. 6.35Equivalence Tie Elements Together .. 6.37Irregularity Checks 6.40FEM Editing Node/Move .. 6.41FEM Editing Node/Offset . 6.42FEM Editing Node/Project 6.43Node Editing Example . 6.44

7.0 ViewingViewing .. 7.3Transformations of View . 7.4Fit Model to Screen and Select New Center 7.5Select Corners (Local Zoom) and Zoom by Factor . 7.6Specify View using Angles . 7.7User Defined Views .. 7.8General Clipping Planes . 7.9



Section Page

8.0 Groups

Introduction to Groups . 8.3Example of Groups .. 8.4Groups Terminology . 8.5Group Manipulation .. 8.6Creating a Group .. 8.7Method of Creating a Group 8.8Display a Group 8.9Modifying Groups . 8.10Moving or Copying between Groups . 8.11Setting Current Group . 8.12Transforming Groups .. 8.13Deleting Groups 8.14Notes on Groups .. 8.15

9.0 Display

Display 9.3Entity Type Display .. 9.4Group Display 9.5Plot/Erase .. 9.6Highlighting 9.8Geometric Attributes 9.9Finite Element and LBC/Element Property Display Attributes .. 9.11Titles Example .. 9.12Spectrums . 9.13



Section Page

10.0 Analysis SetupAnalysis Setup . .. 10.3Setting up the Analysis 10.4Results Translation Back into MSC.Patran . 10.5Reading a MSC.Nastran Bulk Data File .. 10.6

11.0 ListsLists Overview .. 11.3How to Create a List 11.4Boolean Operations . 11.5Boolean Example . 11.6

12.0 ViewportsViewports .. 12.3Why use Viewports .. 12.4Creating Viewports .. 12.5Current Viewport .. 12.6Viewports and Groups . 12.7

13.0 ResultsResults Introduction . 13.3The Results Main Form 13.6Results Plot Types 13.7



13.0 ResultsQuick Plot Form 13.11Quick Plot Animation Form . 13.12Results Post-processing Procedure ...13.13Select Results Form . 13.14Target Entities Form . 13.16Display Attributes Form 13.18Plot Options Form . 13.19Fringe Plot Options .. 13.22Deformed Shape Plots 13.32Vector Marker Plot .. 13.33Marker Display Attributes 13.34Create Results Form 13.35X-Y Graph Plotting .. 13.37Text Report Writer 13.38Freebody Results . 13.41Creating a Range .. 13.43Results with Multiple Viewports .. 13.46Results Animation . 13.47Quick Plot Animation 13.49Animation Control Setup . 13.50Animation Options Form . 13.51Animation Control 13.52Setting up Non-Quick Plot Animation .. 13.53



14.0 X-Y PlottingX-Y Plot . 14.3XY Plot Terminolgy .. 14.4Curve Data from File 14.5Scale and Range . 14.6Titles .. 14.7Modify Display Parameters 14.8Modify XY Window .. 14.9Modify Curve . 14.10

15.0 MSC.Patran FilesMSC.Patran Files 15.3Reverting your Database 15.4Rebuilding a Database 15.5MSC.Patran Files - Generating Hardcopy Plots . 15.6MSC.Patran Files Customization Files . 15.7



16.0 Stress-Life (S-N) TheoryStress-Life (S-N) Theory 16.3Some Definitions . 16.4S-N Analysis . 16.5S-N Curve . 16.6S-N Approach 16.9S-N Curves 16.11Component S-N Curves .. 16.15S-N Method Similitude . 16.18Variable Amplitude Loads Miners Rule and Rainflow Counting 16.20Miners Rule Block Loading . 16.21Nonlinear Damage Theory .. 16.26Rainflow Cycle Counting . 16.29Analysis Route An Overview .. 16.35Influence on Fatigue Life . 16.36Mean Stresses Corrections 16.40Component Size 16.46Type of Loading .16.49Notches .. 16.51Surface Treatment & Finish 16.63How do we get pre-compression? . 16.69Stress Life in MSC.Fatigue . 16.70Goodman based Factor of Safety (f) . 16.71Summary of Total Life Method 16.73Example Problem . 16.75Exercise .. 16.82



17.0 Strain-Life (E-N) TheoryStrain-Life (E-N) Theory 17.3Strain Life Testing . 17.8The S-N and E-N Life Curves . 17.11Materials Characterization .. 17.12The Bauschinger Effect 17.16Masings Hypothesis (Stabilized) Hysteresis Loop) 17.18Strain Control Vs. Stress Control .. 17.20Cyclic Softening 17.21Cyclic Hardening . 17.22Cyclic Stress-Strain Curve Determination 17.23Strain Life Results from a series of LCF Tests 17.27Coffin-Manson-Basquin Equation . 17.29Transition Fatigue Life Calculation 17.31Variability in Material Behaviour and the effects on Fatigue Life Prediction .. 17.33Variable Amlitude Loads Counting Cycles 17.34Rainflow Counting and Stress/Strain Space 17.38Mean Stress Corrections . 17.40Exercise . 17.44Elastic-Plastic Correction and Local Geometry .. 17.45Use of Kf in Strain Life Modeling 17.48E-P Correction including Kf. 17.50Refinement to the Neuber Method . 17.51Seeger-Beste Method and Mertens-Dittman Method . 17.54Surface factors . 17.58Stress Strain Tracking, Neuber Analysis, Material memory and Damage Calculation . 17.60Example Problem: E-N Analysis of a Spider 17.73Exercise .. 17.77



18.0 Multiaxial FatigueWhy do Multiaxial Fatigue Fatigue Calculations? 18.3The Life Prediction Process E-N Approach . 18.4Tensor Representation of Stress State 18.7Stress Tensor Rotation .. 18.10Principal Stresses (and Strains) . 18.11Free Surface Stresses . 18.16Multiaxial Assessment . 18.17Example: Near Proportional Loading 18.18Example: Non-Proportional Loading . 18.21Effect of Multiaxiality on Plasticity, Notch Modeling and damage Modeling 18.23Exercise . 18.24Deviatoric Stresses .. 18.25Yield Criteria .. 18.26Equivalent Stress and Strain Methods .. 18.30Some Equivalent Stress/Strain Criteria . 18.32S-N with Equivalent Stress . 18.33E-N with Equivalent Strain ...18.34Comments on Equivalent Strain Methods .18.38ASME Pressure Vessel Code . 18.40Notch Rules for Proportional Loading 18.43Extending Neuber to Non-Proportional Loadings 18.49Multiaxial Fatigue Theory 18.55MSC.Fatigue Multiaxial Analysis 18.58Normal Strain Method . 18.61Shear Strain Method 18.62



18.0 Multiaxial FatigueSmith-Topper-Watson-Bannantine Method 18.63Fatemi-Socie Method .. 18.64Wang-Brown Method .. 18.66Dang-Van Method 18.72Summary of Approach 18.80A Multiaxial Assessment 18.81Exercise 18.85

19.0 Fatigue Crack PropagationFatigue Crack Propagation (LEFM) Method 19.3Crack Stress Concentration .. 19.6Modes of Crack Opening 19.7Mechanics of Cracks .. 19.8K Controlled fracture .. 19.12Stages of fatigue Crack Growth 19.14Factors Affecting Crack Growth Rate .. 19.19Crack Tip Plasticity . 19.20Mean Stress (R-Ratio) Effects .. 19.22Variable Amplitude Loads . 19.24Environment . 19.25Calculating Lifetimes 19.26Crack Growth Laws . 19.27MSC.Fatigue Crack Growth Analysis Steps 19.29Summary of Approach . 19.32MSC.Fatigue Crack Growth Analysis - Applications 19.33Example Problem: Crack Propagation Analysis . 19.34Exercise . 19.40



20.0 Spotweld FatigueMotivation .. 20.3Structural Stress Based Method 20.5How do we model Spotwelds 20.7Structural Stress Calculations .. 20.9Fatigue Properties Typical Test Specimen . 20.11Damage Calculation Procedure 20.13Results Postprocessing Options .. 20.14Polar Plot of Damage . 20.16Example Problem: A Spotweld Analysis . 20.17Exercise 20.22

21.0 MSC.Fatigue Software Strain GaugeSoftware Strain Gauge 21.4Correlation Applications . 21.6Welded Structure Analysis . 21.8Gauge Definition .. 21.10Implementation . 21.11Example Problem: A Software Strain gauge 21.12Correlation Techniques .. 21.16Exercise . 21.17



22.0 Vibration Fatigue AnalysisOverview .. 22.3Benefits of Vibration Fatigue . 22.5How do we Calculate Damage .. 22.6What is a PSD .. 22.10Expected Zeroes, Peaks and Irregularity Factor from a PSD ... 22.12Probability Density Functions (PDFS) . 22.14Dirlik Solution 22.15Other Solution Methods .. 22.16Summary of Features .. 22.18Example Problem: Vibration Fatigue . 22.20Exercise 22.26

23.0 MSC.Fatigue UtilitiesUtilities Overview . 23.3PTIME (Time History Manager) . 23.5Time History Manipulation Tools 23.6Graphical Editing of Data GED 23.13Time History Analysis/Statistics 23.14Filtering . 23.17Frequency Analysis . 23.19Peak Valley regeneration REGEN .. 23.12Fatigue Analysis (local or test based) Tools 23.23Other Fatigue Related Tools .. 23.24Time Correlated Damage TCD 23.26Stress Concentration Library KTAN 23.27Rosette Analysis SSA .. 23.28Data Conversion and other Utilities . 23.29Exercise 23.30

S1-1PAT318, Section 1, March 2002

SECTION 1

OVERVIEW OF DURABILITY AND FATIGUELIFE ANALYSIS


COMPANY OVERVIEW

n The MSC.Software corporation (formerly MacNeal-SchwendlerCorporation) has been supplying sophisticated computer-aidedengineering (CAE) tools since 1963

n MSC.Software is the developer, distributor, and supporter of the mostcomplete and widely-used structural analysis program in the world,MSC.Nastran as well as the first commercial nonlinear analysis programin the world, MSC.Marc.

u MSC.Nastranu MSC.Marcu MSC.Patranu MSC.Dytran

u MSC.MVisionu MSC.Fatigueu MSC.Laminate Modeleru MSC.Autoforgeu and more


COMPANY OVERVIEW (CONT.)

n MSC.Software Milestones

u 1963 Company founded by Dr. Richard MacNeal andMr. Robert Schwendler. Developed first programcalled SADSAM for Structural Analysis by DigitalSimulation of Analog Methods. This was theforerunner of MSCs flagship program,MSC.Nastran.

u 1965 MSC participates in NASA-sponsoredproject to develop a unified approach tocomputerized structural analysis. The programbecame known as NASTRAN (NASA StructuralAnalysis Program)



u 1965 A team of researchers at Brown University initiated thedevelopment of the technology leading to the MARC program.

u 1971 The MARC Analysis Research Corporation was founded.

u 1972 MSC releases proprietary version of NASTRAN, calledMSC.Nastran.

u 1972 MAR Corporation releases the first proprietary version ofMARC, the first commercial Nonlinear finite element analysis

program.



u 1994 MSC merged with PDA Engineering (Developer of PATRAN)to become the largest single provider of finite elementanalysis (FEA) software to the CAE market.

u 1999 MSC.Software merged with MARC Analysis Research tolead both the linear and the nonlinear analysis worldwideCAE market.


n With corporate headquarters in Santa Ana, California, MSC.Softwaremaintains regional sales and support offices worldwide.

u MSC Technical Support Hotline 1-800-732-7284 (USA/Canada). StaffedMonday through Friday 7:00 a.m. to 3:00 p.m. Pacific Standard Time.

u E-mail support (USA/Canada) [email protected]@mscsoftware.com

u Support (USA/Canada) Fax 714-979-2900u Internet support http://www.mscsoftware.com

MSC CLIENT SUPPORT


COURSE SCHEDULE

Day 1:Intro to Fatigue AnalysisMSC.Fatigue Software OverviewMSC.Fatigue User InterfaceUser Interface ExercisesDay 2:User Interface (Continued)Stress-Life (S-N) TheoryInfluences on Fatigue LifeS-N ExercisesDay 3:Strain-Life (E-N) TheoryMean Stress CorrectionE-N Exercises

Day 3 (Continued):Intro to Multi-axialityHands-On ExercisesDay 4:Crack PropagationLEFM ExercisesSpot weldSoftware Strain GaugeVibration FatigueHands-On ExercisesAdvanced FeaturesMSC.Fatigue Utilities


MSC.FATIGUE FEATURES

n MSC.Fatigue is an advanced Fatigue life estimation program for usewith finite element analysis. It provides state-of-the-art Fatigue analysistools which can be used to optimize the life of a product early in thedesign process. Key capabilities include:u Total Life Analysis (S-N) based on nominal stress-lifeu Crack Initiation Analysis (E-N) or the local strain methodu Crack Growth Analysis - linear elastic fracture mechanicsu Spot and Seam Weld Analysisu Vibration Fatigue analysisu Materials and Time History Databasesu Biaxiality Analysis leading to Multiaxial Fatigue Life Calculationsu Software Strain Gauge and other Utilities


MSC.FATIGUE USER INTERFACE

n MSC.Fatigue has a graphical user interface which consists of thefollowing major components:u Windows-Style User Interfaceu Finite Element Model and Results Importu Analysis Preferencesu Engineering Functionalityu Results Visualization


MSC

MSCFinite Element

AnalysisSoftware

Materials& Loading

Information -MVI - Flightloads

MSC InstituteTrainingServices

TailoredSoftwareSolutions

EngineeringServices

COMPUTER AIDED ENGINEERING SOLUTIONS...


nCodeMSC

MEASUREMENT

TEST

ANALYSIS

DURABILITY MANAGEMENT


A partnership for excellence indurability technology


WHAT IS DURABILITY?


n Durability is

u the ability to do what its supposed tou for as long as its supposed to do it!

n Reliability is

u having half a chance of doing what its supposed to for as long as itssupposed to do it!

LantauTypewriter

LantauTypewriter

LantauTypewriterdo ben


n Fatigue is ...

u the process where repeated variations in loading cause failure even whenthe nominal stresses are below the material yield strength;

n and is

u made up of crack initiation and subsequent crack growth as a result ofcyclic, plastic deformation.


WHAT DRIVES DURABILITYMANAGEMENT?


GOALS, DRIVERS AND REALITIES

n Competition requires FASTER concept-to-customer.

n Costs/profits require CHEAPER products, materials andmanufacturing processes.

n Functionality requires BETTER products with hi-tech features andperformance.

n Legislation requires products with LONGER, more reliabledurability and inspection periods.

n The customer requires the last mile/flight/hour to be the same as thefirst.


Production

Production

Pilot

Engineering PrototypeEngineeringPrototype

Traditional Design DevelopmentCAE Design Objectives

FIX TESTMechanicalPrototype

MechanicalPrototypeConcept

ConceptDevelopment Time

Cum

ula

tive

Cost

DESIGN

CAE for Durability

PRODUCT DEVELOPMENT LIFECYCLE COSTS


Build it

Test it

BeginProduction

OK? Out oftime?NO

NO

YES

Generateidea

Fix it

TRADITIONAL APPROACH WITHOUT CAE:BUILD IT, TEST IT, FIX IT


Generateidea

AnalyseOptimize

Previousexperience

Build it

Test it

OK?

OK? BeginProduction

MeasureCorrelate test& analysisNO YES

NO

ADD CAE: ANALYSE AND OPTIMIZE


CustomerUsage

ProductLife

Build it and Use ItCheck Life Based on

Customer Usage

PREDICTING PRODUCT LIFE 1- BUILD AND USE


CustomerUsage

AcceleratedSign-off Test

ProductLife

Re-Design

PREDICTING PRODUCT LIFE 2- ADD SIGN-OFF TESTING


CustomerUsage


ProductLife

Re-Design

SimulatedComponent

Test

MeasuredServiceLoading

PREDICTING PRODUCT LIFE 3- ADD SIMULATION TESTING


Re-DesignOptimize

SimulatedComponent

Test

Computer-basedFatigue LifeSimulation

CustomerUsage

MeasuredServiceLoading

StressAnalysis

MaterialProperties

Product Life

Correlation

Product Life


PREDICTING PRODUCT LIFE 4- ADD CAE


DESIGNANALYSIS

Structural IntegrityOptimization

DEVELOPMENTANALYSIS

CharacterisationCorrelation with FEAAssess Modifications SIMULATIONTEST

VerificationMonitoringCorrelation

MEASUREDSTRAINS & LOADS

MeasurementValidationCorrection

AnalyticalLoads

KinematicModelling

DATA

DATA DATA

DATA

DATA &CORRELATIONCORRELATION

ModernIntegratedApproach

INTEGRATED DURABILITY MANAGEMENTACTIVITIES


INTEGRATION

n Achieving Faster, Cheaper, Better Integrated DurabilityManagement requires:u Integrated multi-disciplinary teams.u Integrated software tools common to all departments.u Integrated data exchange within company structure.u Integrated data exchange between the company and

its suppliers and service providers.


DESIGN APPROACHES

n SAFE LIFEu Evaluate expected life, use a margin of safety, design to survive

expected service life, then retire.

n FAIL SAFEu Provides redundant load paths, design to fail into a safe condition

and survive until repair.

n DEFECT TOLERANCEu Assumes flaws do exist, design to live with some crack growth

below critical size, requires regular inspections.


Product life used to be a hit and miss affair

Over design 42Under design 7

HISTORY OF FATIGUE EARLY DAYS


A SHORT HISTORY OF FATIGUE - 1

1828 ALBERT tests mine hoist chains under cyclic loading1839 PONCELET designs mill wheels with cast iron axles. First uses

the term Fatigue in a book on mechanics1849 IMechE debate the "CRYSTALLIZATION" theory1850 on WHLER conducts first systematic Fatigue investigations on

axles.Develops the ROTATING-BENDING Fatigue test, S-N curvesand the concept of Fatigue LIMITStarts the development of design strategies for Fatigue. Identifiesimportance of cyclic and mean stresses


Wohlers Railway Component Test Rig


Stress Amplitude

Notched Shaft

Unnotched Shaft

Log (Fatigue life)

Some of Wohlers data for rotating bending tests



1864 FAIRBAIRN experiments with repeated loads1886 BAUSCHINGER first documents Stress-Strain HYSTERESIS1903 EWING & HUMPHREY disprove the Crystallisation theory and

show that Fatigue is due to SLIP1910 BAIRSTOW investigates stress-strain response during cycling

- develops concepts of cyclic HARDENING and SOFTENING1920 GRIFFITH investigates cracks in glass - the birth of

FRACTURE MECHANICS


Persistent Slipband formation

Stage ICrack Growth

Stage IICrack Growth

~1mm

CRACK INITIATION AND GROWTH - STAGE IAND II


MICROSTRUCTURAL CRACK GROWTH

da/dN

a



1955 MANSON and COFFIN investigate Fatigue under STRAINconditions - thermal cycling - low cycle & plastic strainconsiderations

1959 PARIS and ERDOGAN present first systematic method forhandling CRACK PROPAGATION using fracture mechanics

1961 FORSYTH identified stage I and stage II crack propagation1961 - NEUBER proposed a method for estimating elastic-plastic

stresses and strains at stress concentrations1968 - MATSUISHI and ENDO present the rainflow method for cycle

counting


1E0 1E1 1E2 1E3 1E4 1E5 1E6 1E7 1E8

1E-4

1E-3

1E-2

1E-1

1E0

Life Curve Display

L

o

g

S

t

r

a

i

n

Log Life (Reversals)

Total strain curve fit

Elastic strain curve fit

Plastic strain curve fit

Total strain data

Elastic strain data

Plastic strain data

Sf': 670 MPa

b : -0.0582

(X/Y)Ef': 0.374

c : -0.54

E : 2.05E5 MPa

(X/Y): Run-out pts

STRAIN LIFE RESULTS FROM A SERIES OFLCF TESTS



1982 - Battelle Labs in the US estimated annual cost of Fatigue andfracture to the US was 4.4% of GDP (Billions of $) and thatcost could be reduced by 29% by application of currenttechnology

1982 - nCode International established to market Fatigue lifeestimation software & consultancy services

1990 - MSC.Fatigue launched by PDA Engineering


FATIGUE LIFE CALCULATION METHODS

n S-N (Total Life Method)u Relates nominal or local elastic stress to total life

n e-N (Crack Initiation Method)u Relates local strain to crack initiation life

n LEFM (Crack Propagation Method)u Relates stress intensity to crack propagation rate

n All methods rely on SIMILITUDE


Total Life = Crack Initiation + Crack Growth

S-N Local Strain LEFM

f i p


S-N METHOD - SIMILITUDE

The life of this . . . . . . . . . . . . . . . . is the same as the life of this . . . . .if both are subject to the same nominal stress

nom

nom


CRACK INITIATION (STRAIN - LIFE) METHOD -SIMILITUDE

The crack initiation life here . . . . . is the same as it is here . . . . .if both experience the same local strains

e e


CRACK PROPAGATION METHOD - SIMILITUDE

This crack . . . . . . . grows at the same rate as this oneif both experience the same stress intensity factors


"Despite 150 years of Fatigue research, unintended Fatigue failures stilloccur.

More research will NOT reduce the incidence of Fatigue failure - moreeducation will!"

-Quote by Prof. D. SocieUniversity of IIIinois,1990

FATIGUE FAILURE AND TRAINING


THE PHYSICAL BASIS OF FATIGUE

n Fatigue failures typically start at the surface of a specimen orcomponent

n Fatigue failures start at small microscopic cracks and accordingly arevery sensitive to even minute stress raisers

n It has been demonstrated that the Fatigue failure process is related toreversed plastic flow


SLIP AND STAGE I GROWTH

n Under cyclic loading the slip bands tend to group into packets orstriations, forming both ridges and crevices

n There is good evidence that the crevices are closely associated withthe initiation of cracks.

n Small localised deformations (called extrusions and intrusions) mayoccur in the slip bands. These surface disturbances are approximately1 to 10 microns. They constitute initial microcracks.


INITIATION AND PROPAGATION


INITIATION AND PROPAGATION

n The process of Fatigue encompasses the entire range from theformation of a microcrack in a persistent slip band to the propagation ofa long crack in an elastic-plastic continuum.

n There are many ways of starting a small crack:u cracking or debonding of second phase particles,u natural scratches and machining marks on the surfaceu corrosion pits or intergranular attacku porosity from castingu laps from forging and formingu brittle surface layers


USE OF FATIGUE TECHNOLOGY

n Fatigue Technology is not new (50-170 years old);

n A collection of empirical rules to fit observed behaviour;

n Does not require the engineer exploiting it to understand all the finerpoints;

n Can be used (with training and experience) to achieve IDM goals.


FATIGUE CALCULATIONS IN?

n Concept design phase:u Analytical loads, previous design loads, estimatedu properties, early design optimization

n Verification phase:u Measured loads, real properties, designu refinement and optimization

n Production phase:u Continued development, new markets, firefighting


WHO DOES WHAT FATIGUE CALCULATIONS?

n Design analyst:u Design optimization for durability on the virtualu component

n Development engineeru Measures data on the real component, tells theu design analyst where its wrong and how to fix it.

n Test rig engineeru Pre-predicts rig tests and edits out non damagingu parts to speed them up.

n Production engineeru Investigates service failures, monitors production,u feeds back improvement ideas.


DESIGNING AGAINST FATIGUE

n Requirements:u higher performanceu lower weightu longer lifeu reasonable costu as soon as possible


DESIGNING AGAINST FATIGUE

n Constraints:u life calculations are much less precise than strength calculationsu Fatigue properties can not be inferred from static mechanical propertiesu laboratory tests often exhibit scatter and are difficult to translate to full size

componentsu full scale prototype testing is often required to confirm an acceptable lifeu designs should be defect tolerant - stressing and materials selection to

ensure slow crack growth and detectability before failureu where possible designs should be fail safe


GEOMETRY

MATERIALS

ANALYSIS

RE-DESIGNRE-ANALYSE

LIFE(42)

LOADSBLACK BOX

Garbage IN

Garbage OUT

Lots more wronganswers very quickly

Wrong answer

EXPLOITING FATIGUE ANALYSIS - THE 5 BOXTRICK


EXPLOITING FATIGUE ANALYSIS

n The information required for rapid and effective Fatigue analysis can bebroken down into:u a description of the loading environmentu a description of the geometry of the componentu material specific information on the deformation behaviour and Fatigue

properties


DURABILITY TOOLS FOR ANALYSIS AND TEST

n The Fatigue modelling tools used in design analysis and in test analysisuse:u the same time history filesu the same materials databank informationu the same Fatigue algorithms (and similitude)

n The only difference is that the analyst uses an FE model while the testeruses a strain gauge.


INTEGRATED APPROACH TO DURABILITY

n Facts:u Testing is not a good way to optimize designs, but is always required for

sign-off.u Useful Fatigue analysis requires verification and good test-based

information.u Neither Testing nor Analysis have exclusively the right Fatigue answer;

therefore its not an argument between rivals.u Best results are obtained when an integrated approach is adopted

incorporating analysis and testing.


HOW TESTING SUPPORTS ANALYSIS

n Provision of load datan Provision of material Fatigue propertiesn Verification of stress/strain analysis resultsn Correlation of life predictionsn Final sign-off


HOW ANALYSIS SUPPORTS TESTING

n Eliminating unnecessary testsn Test accelerationn Gauge type selection and positioningn Test design


Engineering is the art of being approximately right rather than exactlywrong

-Quote by Prof. Rod SmithUniversity of Sheffield,1990


SECTION 2

OVERVIEW OF MSC.FATIGUE


WHATS IN MSC.FATIGUE?

n Analysis methods:u Stress Life (S-N)u Crack Initiation (E-N)u Fracture Mechanicsu Weld Fatigueu Vibration Fatigueu Multiaxial Fatigueu Spotweld Fatigueu Software strain gauge

n Available in 2 optionsu Integrated in MSC.Patranu Standalone MSC.Fatigue

Pre&Post

n Features:u Time-domain (Quasi-static or

Transient analysis)u Frequency-domain (forced or

random vibration)u Fast preview analysisu Design optimization & sensitivity

analysisu Import from: MSC.NASTRAN,

ABAQUS, ANSYS, MSC.MARC,SDRC Ideas


MSC.FATIGUE CAPABILITIES

Geometry & FEA Results

Test (Lab) Results

Materials and LoadingInformation Damage Distributions

Analysis OptionsStress (total) LifeStrain (initiation) LifeCrack PropagationVibration FatigueMulti-axial FatigueSpot/SeamWeldAnalyzerSoftware Strain GaugeUtilities

Fatigue Life Contours

Sensitivity Analysisand Optimization

1500

-1500120

S

t

r

a

i

n

(

u

E

)

Time (seconds)

DISPLAY OF SIGNAL: TEST101.DAC

Strain Life Plot605M30Sf': 857 b: -0.067 Ef': 0.636 c: -0.579

1E-3

1E-2

1E-1

S

t

r

a

i

n

A

m

p

l

i

t

u

d

e

(

M

/

M

)

1E0 1E1 1E2 1E3 1E4 1E5 1E6 1E7 1E8Life (Reversals)

1E3 1E4 1E5 1E61

2

3

4

5

6

7

Cross Plot of Data : S61STRAIN1KT

Life(Miles)

K

t

(

)

0

1574.7 -750.4

808.70

4.8548

RangeuE

X-Axis

MeanuEY-Axis

DamageZ-Axis

DAMAGE HISTOGRAM DISTRIBUTION FOR : TRACK05.DHHMaximum height : 4.8548 Z Units : %


LIFE PREDICTION PROCESS

Loads Stressor Strain LIFE


LIFE PREDICTION PROCESS: - NAPPROACH

measuredstrains

stress andstrain

componentsLIFE

constitutivemodel

damagemodelconstitutive

model andnotch rule

elastic strainsfrom FEA


ELASTIC STRESS OR STRAIN PREDICTIONMETHODS

n Time-domain:u Quasi-Static method (with or without inertia relief)u Transient method (direct or modal)

n Frequency-domain:u Forced Vibration Response (transfer function method)u Random Vibration (PSD input to / output from NASTRAN)


n Identify set of static FE loadcases and constraints to simulateservice environment

n Measure or predict loading histories Pk( t )n Elastic stress histories calculated from linear superposition:

where k = loadcase i.d.

QUASI-STATIC ANALYSIS

=

k fea,k

k,e,ijke,ij P

)t(P)t(


STRAIN COMBINATION, CYCLE COUNTING,ELASTO-PLASTIC CORRECTION, AND DAMAGE

CALCULATION

LIFE

Material Properties

Range-MeanHistogram

q(t)

[[[[ij]]]](t)

Elastic PlasticConversion &

Damage Calculation

CycleCounting

Combination

q = Max. Absolute PrincipalSigned von MisesSigned TrescaComponent


EXAMPLE - STEERING KNUCKLE


0 500 1000 1500-50.05

84.71Force(Newtons) LOAD03.PVX

point

Sample = 1Npts = 1610Max Y = 84.71Min Y = -50.05

0 500 1000 1500-7998

7720Force(Newtons) LOAD02.PVX

point

Sample = 1Npts = 1610Max Y = 7720Min Y = -7998

0 500 1000 1500-2654

3769Force(Newtons) LOAD01.PVX

point

Sample = 1Npts = 1610Max Y = 3769Min Y = -2654

Screen 1

LOADING HISTORIES


QUASI-STATIC STRAIN CALIBRATION &SUPERPOSITION

Time Histories FE LoadcaseLoadsFE Loadcase

ResultsLocal Strain

Histories

This process is repeated for each node/element


STEERING KNUCKLE


FE ANALYSIS FOR STATICALLYBALANCED CASE

n Ideally determine all Free Body Diagram (FBD) loads (andcheck for static balance)

n At least 6 DOF constraintsn (can be arbitrary if all FBD loads are used)n Redundant constraints must be realisticn Location of constraint may be chosen arbitrarily or for

convenience (e.g. where loads are not easily measured)


FE ANALYSIS FOR STATICALLYUNBALANCED CASE

n Must determine all FBD loads (unless there is partial support,e.g. a hinge)

n Constrain 1 node for 6 DOF (unless there is a hinge forinstance)

n Use Inertia Reliefn Inertia Relief calculates the reaction forces and mass matrix at

the constrained node and redistributes inertia loads according tothe calculated accelerations


TRANSIENT DYNAMIC CASE

n Time histories of stress or strain calculated directly using FE transientanalysis.

n Analysis driven by measured vertical forces, accelerations.n FE analysis time consuming for large models.


Time Domain

Frequency Domain

Fast Fourier Transform (FFT)(throw away phases)

Inverse Fourier Transform (IFT)(create random phases)

Time in seconds

R

e

s

p

o

n

s

e

v

a

r

i

a

t

i

o

n

5 10 15 20

Frequency (Hz)P

o

w

e

r

S

p

e

c

t

r

u

m

Response2Hertz

FREQUENCY DOMAIN

Frequency domain analysis can account for dynamic (resonant) effects


VIBRATION FATIGUE METHODS

50

01494.1410

R

M

S

P

o

w

e

r

(

M

P

a

^

2

.

H

z

^

-

1

)

Frequency (Hz.)

DISPLAY OF NOISE.PSD

Original Title : Stress

0 796Range

Total plot of file NOISE.CYH

753.5

0C

y

c

l

e

s

The PSD can be used to estimate the statistics of the stresshistory and to estimate a PDF of Stress Range


FE MESH CONSIDERATIONS

n FE Stress Analysis is a pre-processing activity for durabilityanalysis

n Global stiffness convergence is a necessary but not a sufficientcondition for a good FE model

n The essential requirement is for good local stress information inthe critical areas

n For crack initiation calculations this normally means goodstresses at free surfaces


MSC/PATRAN - Applications MSC.Fatigue

FIN NOR FNF

PAT3FAT

FES

DAC

TDB

MDB

FPP

FEF

FOS

FALDCLKFCDAC

Fatigue Pre-Processor

Fatigue Results Filter

Re

sult s

Global Fatigue

Analyzer

Factor of Safety

Design

Analyzer

Analyzer

P3/ PA TRAN-A pplic atio

nsOptimization

DHH DYH XYD

LST

Fatigue CrackAnalyzer

CRGKSN Results Listing

TCY

MSC.FATIGUE ANALYSIS PROCESS


Geometry

Materials

Loading

Analysis Post-processing

Optimization

MSC.FATIGUE MAIN FORM


Geometry

Materials

Loading

Results from Linear FE give Load-Strain relationship

Up to 100 simultaneous load(Force, disp etc.) time histories

Strain timehistoriescalculated foreach node bylinearsuperposition

Rainflowcycle count& elastic-plasticcorrection

Analysis

Strain-Life relationship used tocalculate damage per cycle andsummed to give Life

Post-processing

Optimization

Critical nodes can be identified and re-analyzed

Quasi-Static, Strain-Life Example

ANALYSIS PROCESS


METHODOLOGY

Geometry

Materials

Loading


Optimization


GEOMETRY / STRESS-STRAIN RESULTS:

n Linear FE Results (stress or strain)u Linear Static (up to 100 load cases)u Transient Dynamicu Stress Frequency Responseu PSD of Stress Components

n FE Codesu MSC.NASTRANu ABAQUSu ANSYSu MSC.MARCu LS-DYNA3Du SDRCu Others


Geometry

Materials

Loading


Optimization

METHODOLOGY


MATERIALS DATABASE MANAGER

n Facilities foru Data Entry, Deletion, & Editingu Searching on Descriptive Datau Database Entry Listingu Graphical Displayu Multiple Material Designation

DIN, SAE, ASTM, etc.

Aluminum

Steel

TitaniumCopper


A typical S-N curve

S-N Data PlotMANTEN_SNSRI1: 3162 b1: -0.2 b2: 0 E: 2.034E5 UTS: 600

1E1

1E2

1E3

1E4

S

t

r

e

s

s

R

a

n

g

e

(

M

P

a

)

1E0 1E1 1E2 1E3 1E4 1E5 1E6 1E7 1E8 1E9Life (Cycles)

MATERIALS DATABASE MANAGER:


Geometry

Materials

Loading


Optimization

METHODOLOGY


LOADING TIME HISTORY DATABASE MANAGER:

n Facilities for:u Creation (waves, point by point,

graphical, etc.)u Graphical Display and Editingu Arithmetic & Graphical Manipulationu Graphical Cutting and Pastingu Automatic Units Conversionu Searchingu ASCII File Import

TransmissionWind

WavesSuspension


LOADING TIME HISTORY DATABASE MANAGER:

A typicalload historyshowing randomloadingsequences

1500

-1500

120

S

t

r

a

i

n

(

u

E

)

Time (seconds)



Geometry

Materials

Loading


Optimization

METHODOLOGY


STRESS LIFE ANALYSIS (S-N):

n Featuresu Rainflow Cycle Countingu Mean Stress Correctionu Welded Structuresu Statistical Confidence

Parametersu Palmgren-Miner Linear

Damageu User Defined Lifeu Material and Component

S-Nu Surface Conditionsu Factor of Safety Analysisu Biaxiality Indicators

S-N Data PlotMANTEN_SNSRI1: 3162 b1: -0.2 b2: 0 E: 2.034E5 UTS: 600

1E1

1E2

1E3

1E4

S

t

r

e

s

s

R

a

n

g

e

(

M

P

a

)

1E0 1E1 1E2 1E3 1E4 1E5 1E6 1E7 1E8 1E9Life (Cycles)


CRACK INITIATION ANALYSIS (E-N):

n Featuresu Based on Local Strain Conceptsu Mean Stress Correctionu Elastic-Plastic Conversionu Statistical Confidence Parametersu Palmgren-Miner Linear Damageu User Defined Lifeu Cyclic Stress-Strain Modelingu Surface Conditionsu Factor of Safety Analysisu Biaxiality Indicators

s1/2cycle

1cycle

1/2cycle

1cycle1cycle

1/2cycle

e Strain

e

Time


CRACK GROWTH ANALYSIS (LEFM)

n Featuresu Cycle-by-Cycle Modelingu Time-sequenced Rainflow Cycle

Countingu Multi-environment Material

Propertiesu Kitagawa Minimum Crack Sizingu Threshold Modelingu Crack Closure and Retardationu User Defined Lifeu Fracture Toughness Failure

Criterionu Surface or Embedded Cracksu Modified Paris Law


Geometry

Materials

Loading


Optimization

METHODOLOGY


POST-PROCESSING: RESULTS

n Contour Plotting of:u Life Estimatesu Log of Lifeu Damageu Component Specific Life

Units (Flights, Miles, etc.)u Factor-or-Safetyu Multiaxiality Indicators

n X-Y Plots of SensitivityStudies


POST-PROCESSING: RESULTS

n Tabular Results of:u Individual Nodes/Elementsu Most Damaged Nodes/Elementsu Statistical Summary of Damage Distributionu Interactive Results Interrogation of All Life and Damage Estimatesu Factor-or-Safetyu Multiaxiality Indicators


POST-PROCESSING: HISTOGRAM PLOTS

Cycles vs. Damage


POST-PROCESSING: DESIGN OPTIMIZATION

n Localized Analysis forEvaluation ofAlternative:u Surface Conditionsu Material Types /

Parametersu Statistical Confidenceu Design Geometryu Loading Conditionsu Residual Stresses

and StressConcentrations

u Mean Stressu Design Life


POST-PROCESSING: DESIGN OPTIMIZATION

n Search for Better/WorseMaterial

n Allowables Based onDesign Life

n Calibration to TestResults

n Sensitivity Calculationsn X-Y Plottingn Histogram Plottingn User Preferences


ADVANCED FEATURES: MSC.FATIGUE SPOT WELD


STRUCTURAL STRESS BASED METHOD

n Coarse mesh only required, with spotwelds modeled as stiff beam elements

n Beams are used as " force transducers" to obtain forces and momentstransmitted through the spot welds

n Forces and moments are used tocalculate " structural stresses "

n Life is calculated using Miner's rulen Method is generally applicable and

handles multiaxial loading

Spotweld Nugget

( Rupp - Storzel Grubisic)

Beam Element

d


HOW DO WE MODEL SPOTWELDS?

The 5 Box Trick

Optimization& Testing

Loading(Time History)

Material(Weld S-N Data)

Geometry(Beam Elements)

Fatigue Analysis(Spot Weld Analyser)

PostProcessing


STRUCTURAL STRESS CALCULATIONS

The structural stresses are calculated from theforces and moments on each beam element :

Sheet 2Nugget

Sheet 1

Fz

MxFx

Fy

MyMy

Fy

FxMx

Fz

Fz

Mx

Fx

Fy

My


E.G. stresses in sheet :

Similar equations for stresses in nuggetCorrections made for size effect

STRUCTURAL STRESS CALCULATIONS

r

x yFds,max

,

=

rzF

s= 1744 2.

rx yM

ds,max,

.= 1872 2

Fz

Mx

My

Fy

Fx

s

d


FATIGUE RESULTS FOR SHOCK TOWER


MSC.FATIGUE SOFTWARE STRAIN GAUGE

A virtual test facility in theMSC.Fatigue environment


n A Finite Element tool allowing the creation of Stress and Straintime histories at arbitrary locations on a Finite Element ModelSurface

n Uses:u Finite Element Model Results Verificationu Comparison of Strain Values with Test Time Histories

n Previous FEA techniques have only permitted comparison ofsingle Stress or Strain values.

SOFTWARE STRAIN GAUGE


CORRELATION APPLICATIONS

time

H

u

b

S

t

r

a

i

n

Real World Structure FEA Model Surface

SoftwareStrain

Gauges

timeH

u

b

S

t

r

a

i

n


GAUGE DEFINITION

n The gauges are defined as FEA groups, each containing between 1 to 3elements.

n Standard gauge definitions:u Uni-axial Gaugesu T Gaugesu Delta Gaugesu Rectangular Gaugesu Planar and stacked formulations.

n User defined gauges may also be createdu definitions stored in a gauge definition file (gauges.def)


IMPLEMENTATION

n Gauge position:u Anywhere on the FEA model surfaceu Any orientationu Covering multiple finite elements.

n Gauge results:u Averaged results from the underlying finite elementsu Replicates the geometric averaging with actual instrumentation.u Transformed to the coordinate system and alignment of the

software strain gauge.n Up to 200 simultaneous Software Strain Gauges


DIS P L AY OF S IGNAL : NOIS E .D AC

Time (secs)

0.5

-0.6

A

c

c

e

l

(

g

)

0 15

MSC.FATIGUE UTILITIESn Time History Reporting

Tools:u Contour Plots of time

history datau Surface Plottingu Polar Display Facilitiesu Automated Report Quality

Plottingn Time History Manipulation

Toolsu Arithmetic Manipulationu Linear Smoothing

Algorithmsu Fourier Filteringu Butterworth Filteringu Multiple File Manipulation

(Cut & Paste, etc.)u Graphical Editing of Time

Histories


1500

-1500

120

S

t

r

a

i

n

(

u

E

)

Time (seconds)


8191 points.

741 pts/secon

Displayed:

8191 points.

from pt 1

Full file data:

Max = 1499

at 7.105 seconds

Min = -1445

at 9.672 seconds

Mean = 39.89

S.D. = 444.5

RMS = 446.2

0

1414 -487.42

912.570

205

Range

uE

X-Axis

MeanuE

Y-Axis

Cycles

Z-Axis

CYCLE HISTOGRAM DISTRIBUTION FOR : S61STRAINS.CYO

Maximum height : 205 Z Units :

MSC.FATIGUE UTILITIES (Contd.)n Time Series Analysis Tools:

u Running Statistical Analysisu Frequency & Waterfall

Analysisu Probability Density & Joint

Probability Density Analysisu Rainflow Cycle Counting &

Level Crossing Analysisu Strain Gauge Signal Analysis

n Test-based Fatigue Analysis:u Fatigue analysis based on

strain gauge signalsu Total Life (S/N) and Time to

Initiation (-N) analysisu Uses a data base of Stress

Concentration Factors KT forcritical location stressdetermination


InputLoads

Construct FE model anddesignate input and output

nodes

zzyzxz

yzyyxy

xzxyxx

GGGGGGGGG

Calculate 6 componentstresses at each output nodeand compute the principal

stresses

Check stationarity of theprincipal axes

Choose stress parameter andcompute PSD of stress at each

output node

200400

600800 -200

0200

4000

0.51

1.52

2.5

x 10-5

Range [MPa] Mean [MPa]

p(Range,

Mean)

Fatigue Life

MSC.FATIGUE VIBRATION

n Features:u Resolution of stresses

onto Principal planesu Multi input loadsu Correlation effects

using Cross PSDsu Stress tensor

stationarity checksu Calculate Fatigue life

from PSDsu Uses 7 solution

methodsincluding;Dirlik,Steinberg and NarrowBand solutions


WHY USE FREQUENCY DOMAIN?

PSD

frequencyPS

DSt

ress

frequency

Transferfunction

time

W

i

n

d

s

p

e

e

d

FrequencyDomain

Time Domain

OutputInput

time

H

u

b

S

t

r

e

s

s


BENEFITS OF VIBRATION FATIGUE

n Analyse structures with dynamic responses torandom loading without requiring full transientanalysis

n Fatigue analysis is relatively rapidn Analysis can be included much earlier in the

design cyclen Ability to analyse what if scenarios interactively


HOW DO WE CALCULATE DAMAGE?

Material(S-N analysis)

Geometry(FE Analysis)

Fatigue Analysis(Vibration Fatigue)

PostProcessing

Optimization& Testing

Loading(PSD)


HOW DO WE CALCULATE DAMAGE?

FatigueMODELLER

BLACKBOX

M0M1M2M4

Transfer

Function

PSD

TransientAnalysis

RAINFLOWCOUNT

TIMEHISTORY

TIME DOMAINSteady

stateor

PDF

FatigueLIFE

STRESSRANGE

HISTOGRAM

FREQUENCY DOMAIN


MULTIAXIAL FATIGUEn Handles proportional and

non-proportional loadingsn Incorporates Mroz-Garud

model and energy basednotch correction procedure

n 6 critical plane damagemodels including Wang-Brown method and Socie-Bannantine shear andnormal models

n High cycle (Fatigue limit)calculations using theDang-Van and MacDiarmidmethods.

n Post-processing includingpolar damage plots

0

30

6090

120

150

180

210

240270

300

330

1E-9 1E-8 1E-7 1E-6

Polar Plot of Data : DEMO

Theta=90 Theta=45

Polar Plot of Type A and Type B damage for Wang-Brown Method


SECTION 3

MSC.FATIGUE USER INTERFACE


LoadingData

Geometry

MaterialsData

Computer-BasedAnalysis Life

The Three Inputs The Analysis The Answer!

THE FIVE BOX FATIGUE LIFE ANALYSIS TRICK


OVERVIEW OF MSC/FATIGUE ANALYSISPROCESS

n Define Loading Historyn Define Fatigue Material Propertiesn Set Up and Run the Fatigue Analysisn Select Solution Parameters

u Select Solution Parametersu Submit the Jobu Monitor the Job Progressu Read in the Results

n Evaluate Resulting Life Predictions


2 - Import Geometry 1 - Select Analysis Code

2 - Build Geometry

3 - Create Analysis Model

4 - Perform the Analysis

5 - Evaluate Analysis Results

RUNNING AN FEA USING MSC.PATRAN


OR IMPORT THE MODEL AND RESULTS

n Use Results from a Previous Stress Analysis

n Import Nodes and Elements and Stress/Strainsfrom the Results File (.op2 for MSC/NASTRAN)

n Use Model and Results Filtering to reduce Modelsize and Fatigue Analysis Run Times


MSC.FATIGUE MAIN FORM

n General setup parameters are used to definegeneric parameters for the Fatigue job

n Jobnames and Titles are used to identify FatigueJobs in MSC.Patran

n Specific setup forms are used to specifyparameters unique to fatigue analysis such asfatigue material properties, load time histories, etc.

n Job control is used to submit and monitor fatiguejobs

n Results is used to post-process fatigue results


Loading Time Histories may beimported, created, modified, anddisplayed by clicking on theDatabase Manager button

Result Parameters define thestress analyzers result details

A Loading Time History is selectedby clicking on the appropriatename in the list box

LOADING INFORMATION FORM


MATERIAL INFORMATION FORM

n Fatigue Material Propertiesare created / reviewed byclicking on the DatabaseManager button

n The fatigue materialproperties may be selectedby clicking on its name in thematerial list box

n Clicking on the O.K. buttonwill save the specifiedproperties and hide the form


SOLUTION PARAMETERS FORM

n The Solution Parameter form is used to definefatigue analysis specific parameters

n Clicking on O.K. will save the suppliedinformation for future retrieval

n Clicking on Cancel will close the form withoutsaving the altered data values


MSC/PATR AN - Applications MSC/FATIGUE

FIN NOR FNF

PAT3FAT

FES

DAC

TDB

MDB

FPP

FEF

FOS

FALDCLKFCDACFatigue Pre-Processor

Fatigue Results Filter

Re

sults

Global Fatigue

Analyzer

Factor of Safety

Design

Analyzer

Analyzer

P3/PATRAN

-Application

sOptimization

DHH DYH XYD

LST

Fatigue CrackAnalyzer

CRGKSN Results Listing

TCY

MSC.FATIGUE FILES


Files Created in MSC/FATIGUEFilename Description

jobnameFIN Job parameter file (ASCII)jobnameFNF Neutral file for P3/FATIGUE

jobnameFES P3/FATIGUE input filejobnameASC ASCII version of the JOBNAMESFES file*DAC Loading time history file

jobnameFPP P3/FATIGUE intermediate results filePFATIGUE.PRT P3/FATIGUE session filejobnameMSG P3/FATIGUE message filejobnameSTA P3/FATIGUE status filejobnameABO P3/FATIGUE alert filejobnameFEF Global multi-node analysis results filejobnameRMN Results menu filejobnameFPR File to indicate job running in current directoryjobnameTCY Time ordered stress cycles file*KSN K solution filejobnameCRG Crack growth results file

jobnameKFL Stress concentration-Life XY datajobnameDCL Design criterion-Life XY datajobnameFAL Scale factor-Life XY datajobnameCYH Rainflow cycle distribution at node njobnameDHH Damage distribution at node njobnameFOS Factor of safety results file


JOB CONTROL FORM

n Fatigue Analysis Jobs are submitted to thelocal host using the job control form

n The Job may be monitored on a regularbasis

n Jobs may also be aborted from this form


RESULTS FORM

n The Fatigue results for completed jobsmay be read into MSC.Patran

n The results may be displayed usingstandard MSC.Patran post-processingfunctions

u Results

u Insight


GRAPHICAL DISPLAY OF FATIGUE RESULTS

n Fatigue results may be displayed by selecting the Results switchfrom the top menu bar

n Fatigue results includeu Damageu Log of Damageu Life (repeats)u Log Life (repeats)u Life (User Defined Units) e.g. Laps, Flights, etc.u Log of Life (User Defined Units)


SECTION 4

OVERVIEW OF PATRAN


BUILDING A MODEL USING MSC.PATRANThe Main Form

2 - Import Geometry 1 - Select Analysis Code

2 - Build Geometry

3 - CreateAnalysis Model

5 - EvaluateAnalysis Results

4 - Perform theAnalysis


STEP 1 - ANALYSIS PREFERENCES

n Appears when creating a new databasen Used for specifying global model tolerance.

An entity within the tolerance of another isconsidered to be a duplicate. Also, twoentities within the tolerance of each otherare considered to be coincident.

n Alternative method for specifying globalmodel tolerance is Preferences/Global

New Model Preferences


STEP 1 - ANALYSIS PREFERENCES(CONTINUED)

n Select/Revise Analysis Code Preferencebefore defining Materials, ElementProperties, or Load/Boundary Conditions

n Analysis Preferences eliminates theconfusion


STEP 2 IMPORT/BUILD GEOMETRY

n Geometric Modeling:u Import a CAD Model from

l CATIAl Pro/ENGINEERl CADDS 5l EUCLID-3l Unigraphics

u Import a CAD model via an IGES,ACIS, Parasolid-XMT, or STEPfile

u Build the geometry model entirelyin MSC.Patran X

Y

Z

Imported CAD model


STEP 3 CREATING AN ANALYSIS MODEL

n Nodes and Elements (connectivity) canbe created byu Mapping Mesher (IsoMesher)

l 3 or 4 sided surfaces (displayed as Green)l 5 or 6 faced solids (displayed as Blue)

u Paver Mesherl N-sided (edged) trimmed surfaces

(displayed as Magenta)l 3 or 4 sided surfaces (displayed as Green)

u Auto TetMesherl N-faced solids, B-rep Solids (displayed as

White)l 6 faced solids (displayed as Blue)

u Sweeping Base Elements Meshern Mesh Seeds are used to define the node

density and spacing

Finite Element Mesh

Quads swept to Hex Elements

X

Y

Z

Mapped Mesher Quad Elements

X

YZ


STEP 3 CREATING AN ANALYSIS MODEL(CONTINUED)

n Check the quality of the finite element modelu Element Boundary Checks (crack detection)u Element Nodal Connectivity (Normals, Negative Volume)u Element Distortion Checks (Aspect Ratio, Face Taper, etc.)

n Elements are color-coded based on user-defined criteria

Verification

Y

Z X

.2372

.2214

.2056

.1898

.1740

.1582

.1423

.1265

.1107

.09490

.07908

.06326

.04745

.03163

.01582

.0000007040



n The material properties can be manually input, accessed from theMSC.Patran Materials Selector, input externally

Material Properties

Manual Input Materials Selector

Materials Selector

Query Command

Current Database: mil5f_cn2.des Auto Execute

CNAME (Common Name): 15-5PH Stainless SteelSelected Cell Data

CNAME

17-4PH Stainless

17-4PH Stainless17-4PH Stainless

15-5PH Stainless15-5PH Stainless

DENS

0.282

0.2840.283

-0-0.283lb/in^3

E11C

3e+07

3e+073e+07

-0-2.92e+07psi

Row 3 of 95

Row 5 of 95Row 4 of 95

Row 2 of 95Row 1 of 95

17-4PH Stainless -0- -0-Row 6 of 9517-7PH Stainless 0.276 3e+07Row 7 of 9517-7PH Stainless -0- -0-Row 8 of 95

ClearApply

Display Materials Properties...

Query...Select Database... Column Headers...



n Element type and physical properties defined with theProperties application

n Once the analysiscode preference ischosen only permittedphysical properties areavailable

n If detailed informationis needed, theinterface manuals areon-line

Element Properties



n Applied directly to the geometry or FE modeln Variations defined by fieldsn XY Plots used to verify the field

LEGENDForce Variation

1.00 5.00 6.004.002.00 3.000.

360.

240.

180.

120.

60.

300.

0.

X

Y

Z


STEP 4 PERFORM THE ANALYSIS

n Select code-specific solutionprocedures and parameters

n Submit directly fromMSC.Patran


STEP 5 EVALUATE RESULTS

n Displayed with Results or Insight applicationsn Filtered based on model attributes, numerical values

or user-defined criterian Different results displayed concurrently using multiple

viewports Time: 10:58:26Date: 11/30/94IsosurfaceVal= 0.5000E+03Node Scalar1Color Index

BA0987654321

Min = 2.442558E-01Max = 2.380629E+03Min ID = 1730Max ID = 950Isos_1:STRESSCOMPONENTSVon Mises(NON-LAYERED)DefaultMax DEFLECTION = 1.82E-03

0.129E+040.121E+040.113E+040.105E+040.968E+030.887E+030.806E+030.725E+030.643E+030.562E+030.481E+030.400E+03


WHERE TO GO FOR HELPMSC.Patran Product Coordinator at your company

Technical Support for all MSC.Patran productsEmail support at [email protected] (714-979-2990)

MSC.Patran SUPPORT Hot Line (1-800-732-7284)

Monday through Friday 7 am to 3 pm Pacific Standard TimeMSC.Software Website (http://www.mscsoftware.com)MSC.Software Institute (1-800-732-7211)

Training Classes offered for all MSC.Patran productsE-mail support at [email protected] held regularly at domestic and international MSC.Software offices


Site Specific Form

Cancel

Site Specific Application

Site Specific Geometry Access...

Acoustic Analysis...

Experimental modal Import...

CUSTOMIZATION

n PCL MSC.Patran Command Languagen PCL can be used to create custom-made

menus and formsn Use PCL to automate repetitive tasks and

apply complicated Load/BCsn MSC Institutes PAT304 course shows

how to do all of the above

Site SpecificItem...

Customer Options


STARTING MSC.PATRAN

In the terminal window click the desk top icon to invokeMSC.Patran or type Patran

MSC Patran

Welcome to MSC.Patran Version 9.022600 03:36:58 PMSetting up Windows Environment


MSC.PATRAN FILE OPTION

q New Database Create a new empty databaseq Open Database Open a previously created databaseq Revert to Original Database Allows the deletion of all the changes

made in the current modeling session(Revert must be enabled for this to beavailable)

q Session... Execute PATRAN commands from afile

q Close Close the current database but keepPATRAN active

q Quit Close the current database and stopPATRAN

q Save Saves the database up to andincluding the last command

q Save a Copy Save a copy of the database under adifferent name


MSC.PATRAN FILES

Created using Export. Can be used as abackup for analysis model.

Neutral Filemodel_name.out

One per model, record of all PCL commandsfrom database creation to present,concatenated session files. EXTREMELYuseful for rebuilding a database.

Journal Filemodel_name.db.jou

A Session File is opened at P3 start-up and itis closed when you quit MSC.Patran.

Session Filepatran.ses.number

Backup database is created if revert isenabled.

DatabaseModel_name.db.bkup

One per model, relatively large.DatabaseModel_name.db

CommentsFile TypeName


THE MAIN FORM

n Menu Bar selection affects global environment (e.g. Viewing, Imaging,and Preferences)

n Application selections only apply to a certain portion of the model (i.e.Geometry, Loads/BCs, etc.)

n Application selections are mutually exclusive -- only one can beselected at a time

n Unavailable selections are shown in a lighter typeface (Ghosted)

Menu Bar

Applications History BoxCommand Line Tool Bar


THE MAIN FORM (CONCLUDED)

n Tool bar provides quick access to frequently used proceduresn Actions taken within MSC.Patran session can be traced in the history

boxn Command line allows the input of PCL commands and MSC.Patran2

NOODL Rule commands


TYPICAL WIDGETS USED IN MSC.PATRANq Toggle button is an on/off

switch

q Select databox is usedto enter data

q Data insertion can bemade by placing themouse at the desiredlocation, clicking theleft mouse button, andtyping in the desireddata

q Existing text can beedited

q Data selection is done byhighlighting item

q Radio buttons allowexclusive selection amongoptions

q ... Suffix denotes that asubordinate form will openup upon clicking the button

q Apply causes action toexecute

q Hyphens indicate action canbe undone only immediatelyafter its execution

q Slide bar assigns a value to associated variable; i.e.threshold for aspect ratio test

q Control icon allows the switching between different actions;i.e. icon can be set to highlight or split in this example

q Causes the content of a form to reset back to default values;the default values may be constant or can change


SYSTEM ICONS

Refresh Button - refresh screen

Undo Button -

Display Cleanup Button - resets graphics todefaults

will undo just last command. When anaction is performed, the created data issaved in the computers memory. When thenext action is performed the data previouslywritten to memory will be saved in the Patrandata base.


SYSTEM ICONS (CONCLUDED)

Interrupt Button - stops operation in progress

Heartbeat - Green indicates MSC.Patran is waitingfor user input

- Blue indicates MSC.Patran isperforming an operation that can bestopped with the interrupt button

- Red indicates that MSC.Patran isperforming a process that cannot beinterrupted


ENTITY PICKING

n Picking is performed in two ways:u Keyboard entry into a databox,

e.g. Curve Listu Graphical picking with the mouse

n List processor is the program responsible for the interpretationof the user input, e.g. Curve 1:3


ENTITY GRAPHICAL PICKING

n Individual and collective entity picking is controlledby the Picking option under Preferences

n For Single Entity Picking, a portion of the selectedentity must be within the physical limits of thecursor

n For Centroid Single Picking, the closest entity tothe location of the cursor will be picked

n Additional tools are available to aid the process ofpicking, such as Cycle picking

n The Preselection Settings highlight the Entity andLabel (ID #) of the entity before you select it


CURSOR PICKING

Entity Move the cursor to the entity label/centroid and pressthe left mouse button

Multiple Picking Hold the shift key down and select the entitieswith the left mouse button`

Shift


CURSOR PICKING (CONTINUED)

Ctrl

Select Rectangle (Click & Drag)

Select Polygon

You may alsoselect this iconfrom the toolbar Note: To complete your selection double click the left

mouse button


CURSOR PICKING (CONCLUDED)

Deselect

Cycle Picking

If you hit the space bar while an entity is selected itwill temporarily erase the entity so you can select theone underneath

Shift

Move the cursor to the entitys label/centroid andclick on the right mouse button

Picking an entity underneath another, or that isclose to other entities. Selection

Surface 3Surface 7

Previous Next


VIEWING/MODEL MANIPULATION

-x

+y

+x

-y

MouseRotate XY

MouseRotate Z

MouseTranslate XY

MouseZoom


LIST PROCESSOR

n The list processor verifies the syntax, checks for existence andperforms rudimentary geometry operations such as calculating theintersection of two curves

n The list processor parses the contents for the select databoxn The application only recognizes specific types of datan The list processor is generic and is used by all applications for

consistency


ENTITY ID SYNTAX

Signifies an axis with first point representing the base and the seconddetermining the direction

{[ ][ ]}

< > signifies a vector definition

Mathematical operations like division are possible to determine theindividual components

[1, 2, -64.0/20.0]

y = the z coordinate of point 5When a point is referenced the letter p can be dropped

[1, zp5, 3][1, z5, 3]

Individual coordinates can reference existing entities, such as x = the xcoordinate of node 28

[xn28, 1, 2]

Square brackets signifies coordinate specification[x y z]

Combinations of entity ID syntax is possible (face 2 of solids 1 through10)

Solid 1:10.2

References an entity associated with a higher order one (i.e. edge 1 ofsurface 3, that is similar to a curve)

Surface 3.1

Different forms for delimiters: space, , and /Curve 1 2, 3/ 4

Points 1 through 9 by 2Point 1:9:2

Refers to points 1, 2 and 3Point 1 2 3

DescriptionSyntax


MSC.PATRAN STANDARDS

If your cursor becomes a pointing hand:

This means there is an error window somewhere onyour screen that must be acknowledged before youcan continue

Sample Error Window


ON-LINE HELPActivation

To start, click on Help by system icons


ON-LINE HELP (CONTINUED)

n There are two ways to use the help system:u Topical help allows the user to access the complete MSC.Patran

Help Systeml General MSC.Patran Philosophyl Tutorials on the use of MSC.Patranl Features and Functions

u Context sensitive help is used to describe the contents of a form inquestion - F1

System


ON-LINE HELP (CONTINUED)Top Menu

The following navigation menu appears at the top of each help pagePart 3: Geometry ModelingAccessing/Importing/ExportingPage 2-2

Options Done

- Select an Option-LibraryContentsIndexGetting StartedExamplesSales & SupportHelp on Help

Page Locator Brief title of the current help pageOptions Allows the user to access other documents in the system

Trace back to previously displayed pagesPage backward & forward

Done Exit help document


SECTION 5

GEOMETRIC MODELING


TOPOLOGICAL STRUCTURES

n MSC.PATRAN combines topological structures to define geometryn The topological entities within MSC.PATRAN are:

n Vertices hold positions for an edge, face, and bodyn All topological entities can be cursor selected to perform MSC.PATRAN

functions (e.g. Surface 10.2)

7

VertexFace

Edge1

3

5

6

8

Body

4


GEOMETRY BUILDING BLOCKSPoint (Cyan)

n A point is a 0 dimensional CADentity; it represents a location inspace; 3-space in MSC.PATRAN

n MSC.PATRAN creates pointsautomatically when constructingcurves, surfaces, and solidsu Points are created at vertices, e.g.

surface vertices (corners)u It is not always necessary to

construct entities starting with theirpoints, e.g. surface going from pointto point

ZX

Y

Y

X

Z

9


GEOMETRY BUILDING BLOCKS (CONTINUED)Curve (Yellow)

n A curve is a general vector function of thesingle parametric variable 1; it can havemany types of mathematical forms:

n A curve has:

u Two points, with one at each endu A parametric coordinate (1) whose domain

is from 0.0 at P1 (its origin) to 1.0 at P2n Meshed with bar elements

(X,Y,Z) = function (1)

1

P2

1P1

P(1)

Z

YX

Z

X

Y

5

5Bar Element


GEOMETRY BUILDING BLOCKS (CONTINUED)Surface (Simple or complex)

n Surface types can be simple (Green) orcomplex/general (Magenta)

n A simple surface is a general vector functionof the two parametric variables 1,2:

n A simple surface has:

u 3 or 4 bounding edgesu A parametric origin and parametric coordinates

whose domains are from 0 to 1n A simple surface with 3 visible edges has a

fourth edge that is degenerate

(X,Y,Z) = function (1,2)12

P2P1

P4 P3

2

1

2

1

Z

YX

Z

X

Y

P(1,2)


GEOMETRY BUILDING BLOCKS (CONTINUED)Surface (continued)

n A simple surface can be meshed with either the IsoMesh (mapped) orPaver (free) meshers

IsoMesh Mesh of Surface 1Nodes follow curves of

constant parametric value

1

2

3

4

1

Curve of constantparametric value

2/3

1/3

1/3

2/3

1

2

1

2

3

4

1

Display Line forvisualizing surface

Surface 1


GEOMETRY BUILDING BLOCKS (CONTINUED)Surface (concluded)

n A complex or general trimmed surface (magenta) has more than 4edges (N-sided) and can have inner boundariesu Not defined parametrically, e.g. 1,2 not usedu It is a trimmed parametric surfaceu Must be meshed with the Paver mesheru Meshes perimeter of surface first

General TrimmedSurface

181920

21

22

2324

25

Paver MeshPerimeterof surface


Y

Z X

1

2

3

P8

P7

P6

P4

P3

P2

P1

P5

P(1,2,3)

GEOMETRY BUILDING BLOCKS (CONTINUED)Solid (Simple or Complex)

n Simple or parametric solid (blue)u Vector function of three parametric variables

1,2,3n A simple solid has:

u 4 to 6 bounding facesu Parametric origin and coordinates whose

domains are from 0 to 1n A simple solid with 4 to 5 visible faces has

some degenerate facesn Parametric solids are meshed with the

IsoMesh (mapped) mesher (hex, wedge, ortet elements)


TetrahedralMesh

B-RepSolid

GEOMETRY BUILDING BLOCKS (CONTINUED)Solid (concluded)

n Complex or non-parametric solids (N-faced) (white)u Non-parametric solids can be either Patran native B-Rep (boundary

representation) or parasolid B-Repu CAD solids can be accessed as B-Rep or parasolid solids and can be

meshed using the automatic TetMesh algorithmu Meshes faces with tri-s, then perimeter of solid with tet-s first


Plane Vector

GEOMETRY BUILDING BLOCKS (CONCLUDED)Planes, Vectors

n Infinite planes and vectors are used for certain geometric operations,such as solid break by a plane

n A plane is uniquely defined by vector representing its normal and apoint on the plane

n A MSC.PATRAN vector quantity is defined by a magnitude, adirection and a point of origin


IMPORTING, EXPORTING GEOMETRY ANDFEM


FILE IMPORT OPTIONS


FILE IMPORT OPTIONS (CONCLUDED)

Geometry kernal type

CAD part

Standard format


EXAMPLE UNIGRAPHICS CAD MODELIMPORT

n Select Import... from the File menun Set Unigraphics as the Sourcen Select desired UG part filen Optional filtering of entities is available based on

entity type (e.g. Sheet Body), CAD layer and ifsewing is to be done


EXAMPLE UNIGRAPHICS CAD MODEL IMPORT(CONCLUDED)Unigraphics options

n Filter Options include:u Entity Typeu Entity Layersu Trimmed Surface Typeu Sew Sheet Bodies

Unigraphics Options... is used to filter the Unigraphicsentities being imported


MSC.PATRAN DATABASE ACCESS

n MSC.PATRAN database content can be transferred between differentdatabases

n Import option allows the specification of entity type, ID offset, nameprefix, and conflict resolution tools

n Equivalence Option allows common entities in the databases to beequivalenced

n Preview option provides access to summary information


MSC.PATRAN DATABASE ACCESS(CONTINUED)

n MSC.Patran databases canbe accessed by selectingMSC.PATRAN DB as thesource



n Importing options controlsu Which entities to importu How to import entitiesu Resolve conflict



n Merged finite element models may beequivalenced

n Options on how MSC.PATRAN will deal withDiscrete deal with Discrete FEM Fields onimport


FILE EXPORT OPTIONS


FILES EXPORTED

n IGES fileu Points and all curve and surface types, e.g. trimmed parametric

surfaceu No geometric solidsu FEM nodes and elementsu No results

n Patran neutral fileu Parametric cubic geometryu FEM consisting of nodes, elements, material properties, element

properties, coordinate frames, etc.u No results


FILES EXPORTED (CONCLUDED)

n Parasolid xmt fileu Specific types of parasolid geometryu Can specify the parasolid version

n Step fileu AP203 geometry onlyu AP209 geometry, mesh, analysis, and/or results


GEOMETRY CONSTRUCTIONn Geometry can be constructed in MSC.PATRAN by:

u Editing imported CAD geometry (Edit/Surface/Sew)u Building with respect to existing geometry (Create/Solid/Extrude)

u Creating copies of existing geometry (Transform)

Extracting a Curve Gliding a Solid from a Surface

Rotating Mirroring

1


GEOMETRY FORM ANATOMY

n The strategy behind working with the geometryform:u Set an objective, such as creating a pointu Provide the details associated with creating the

entity using the specified method

Action

Object

MethodSurface

XYZ

Face

Revolve

Curve

XYZ

Trimmed

Revolve

Point

Manifold

Chain

Revolve

XYZ

Interpolate

Extract

Project

Cr

durability and fatigue life analysis using msc.fatigue

Documents

trademarks of msc

short history of fatigue

fatigue lifeanalysis

fatigue failure

fatigue features

service marks of msc

fatigue lifecompany

prior written consent