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03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by...

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FEA-Crack Software Ted L Anderson, Ph.D., P.E. March 7, 2007
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Page 1: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

FEA-Crack Software

Ted L Anderson, Ph.D., P.E.March 7, 2007

Page 2: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Company Overview

Structural Reliability Technology (SRT) founded in 1995.SRT acquired by Quest Reliability, LLC on January 1, 2007.Approximately 50 engineers worldwide, including 15 with Ph.D. degrees.Office locations:• Boulder, CO• Houston, TX• Wellington, New Zealand• Brisbane, Australia

Page 3: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Company Overview(cont.)

Broad range of services:• Fitness-for-service & fracture mechanics• Stress analysis• Failure analysis• Software development

Diverse group of clients• Power• Chemical, petroleum, petrochemical• Pipeline• Rail transportation• Defense• Aerospace

Page 4: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or
Page 5: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

FEA-Crack Overview

Pre- and post-processor for 3D crack problems.Front end to Abaqus, ANSYS, and Warp3D.Drop-down list of component/geometry choices (20 & counting).User-defined geometry option for cases not covered in list.Crack growth modeling• Re-meshing• Element deletion• Node release• Cohesive elements

Page 6: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Partial List of FEA-Crack Customers

NASA Marshall Space Flight CenterLos Alamos National LaboratoryExxonMobilShellBPChevronWestinghouseSouthwest Research InstituteRolls RoyceBoeingDominion Engineering

Page 7: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Crack Meshing

Page 8: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Crack Tip Region

Page 9: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or
Page 10: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or
Page 11: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or
Page 12: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Crack Front Profile

Straight line crack front

“Thumbnail” custom crack front

Page 13: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Meshing Controls

Coarse mesh

Refined Mesh

Page 14: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Variable Crack Dimensions

Shallow Crack

Deep Crack

Page 15: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Post ProcessingJ-Integral Plot

Page 16: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Post ProcessingStress Intensity Results

Page 17: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

The J-IntegralPath-Independent Line Integral

i ij jT nσ=

ii

uJ wdy T dsxΓ

∂⎛ ⎞= −⎜ ⎟∂⎝ ⎠∫

Where Γ is an arbitrary counter-clockwise path around the crack tip and:

0

ij

ij ijw dε

σ ε= ∫

Γds

x

y

For 2D problems, the line integral can be converted to an area integral for evaluation with finite element analysis.

In 3D, a surface integral is converted to a volume integral.

Page 18: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

The J-IntegralNonlinear Energy Release Rate

dU

Displacement

Load P

( )21IKJ

Eν−

=

In the limit of linear elastic material behavior, J = G and:

assuming plane strain conditions.

1 dUJB da ∆

⎛ ⎞= − ⎜ ⎟⎝ ⎠

Page 19: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

KI from J Example 1Griffith Plate

0.96

0.98

1

1.02

1.04

1 2 3 4 5

1/4 - Point Node inFirst Element Ring

Mid-Point Node inFirst Element Ring

Contour #

Through Thickness Crack in Flat PlateSubject to a Uniform Crack Face Pressure

2D Plane Strain Analysis

JKaσ π∞

Page 20: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

KI from J Example 23D Griffith Plate

Page 21: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

KI from Crack Opening Displacement

Similar expressions exist for Modes II and II

( )20

21 limI y

r

EK urπ θ π

ν →

⎡ ⎤= =⎢ ⎥− ⎣ ⎦

x

y r

θuy

Page 22: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Displacement Extrapolation

θ = π

KI

r

2

21

yEurπ

ν−

Page 23: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Displacement Method ExampleGriffith Plate

0.9

0.95

1

1.05

0 0.02 0.04 0.06 0.08 0.1

Baseline Model2x Refinement8x Refinement

( )uIK

aσ π∞

Through Thickness Crack in Flat PlateUniform Crack Face Pressure

2D Plane Strain Analysisθ = π

r/a

Page 24: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

FEA-Crack Validation Methods

Compare results to known cases (e.g. buried crack in infinite solid).Compare results from 2 different methods (e.g. K from J versus K from displacement).Compare results with published solutions.Compare results from different finite element solvers (e.g. Abaqus versus ANSYS).Perform mesh refinement convergence study.

Page 25: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Benchmark Example

Page 26: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Incorporation of Weld Residual StressesMap Residual Stresses with Crack Closed

Page 27: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Incorporating Weld Residual StressesAllow Crack to Open

Page 28: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

User-Defined GeometryInitial Uncracked Mesh

Page 29: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

User-Defined GeometryRemove 6-Sided Primitive

Page 30: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

User-Defined GeometryInsert New 6-Sided Primitive with Crack

Page 31: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

User-Defined GeometryFEA Results

Page 32: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Crack Growth in a Finite Element ModelExamples of Available Methods

Re-Meshing (Elastic Only)Element Deletion (e.g. Gurson-TvergaardPlasticity)Node ReleaseCohesive Elements

Page 33: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Crack Growth in a Finite Element ModelMesh Types

Focused Mesh• Remeshing

Cell Mesh• Element Deletion• Node Release• Cohesive Elements

Page 34: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Cell Mesh for Crack Growth Analysis

Page 35: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Remeshing ExampleSurface Crack in Wind Turbine Rotor

Small Initial Surface Crack

Page 36: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Dynamic Simulation of Charpy Test

Page 37: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Collision/Fracture Simulation

Page 38: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

New FEA-Crack DevelopmentFunded by EPRI

Add custom-shape surface crack with K-driven crack growth,where da/dt (or da/dN) is computed at each node point along the crack front.Impose non-uniform temperature distribution in weld to mimic residual stresses.Add rigid contact surface to crack symmetry plane to model crack closure.Add additional functionality to custom through crack.Add “nozzle to safe end” geometry to drop-down list.

Page 39: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Custom Surface Crack Input

Page 40: 03/07/2007 Industry Handouts/Slides, 'FEA-Crack Software ... · New FEA-Crack Development Funded by EPRI Add custom-shape surface crack with K-driven crack growth,where da/dt (or

Custom Surface Crack Mesh


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