nafems compomethods and technology for the analysis of composite materialssiteswebinar 2007 all inc

Methods and Technology for theMethods and Technology for the Analysis of Composite Materials

September 24, 2007

AgendaAgendaNAFEMS Methods and Technology for the NAFEMS Methods and Technology for the gygyAnalysis of Composite Materials WebinarAnalysis of Composite Materials Webinar

September 24, 2007September 24, 200711:00am ET (GMT 11:00am ET (GMT --04:00, New York)04:00, New York)

Welcome & Introduction (Overview of NAFEMS Activities)Welcome & Introduction (Overview of NAFEMS Activities)Matthew Ladzinski, NAFEMS North American Representative

Methods and Technology for the Analysis of CompositeMethods and Technology for the Analysis of Composite Materials

Dale Berry, SIMULIA

Failure Simulation of Z-pinned CompositesKyle Indermuehle, ATA Engineering

Q&A Session Panel

Cl i

www.nafems.orgwww.nafems.org

ClosingBerry Indermuehle

THE INTERNATIONAL ASSOCIATIONTHE INTERNATIONAL ASSOCIATIONTHE INTERNATIONAL ASSOCIATIONTHE INTERNATIONAL ASSOCIATIONFOR THE ENGINEERING ANALYSIS FOR THE ENGINEERING ANALYSIS

COMMUNITYCOMMUNITY

An Overview of NAFEMS Activities

Matthew LadzinskiMatthew LadzinskiNAFEMSNAFEMSNorth American RepresentativeNorth American Representative


Planned Activities in North America

Work Session on the Management of Simulation Work Session on the Management of Simulation Data Data

Take Control of Your Analysis and Simulation DataTake Control of Your Analysis and Simulation Data September 27, 2007September 27, 2007 www.nafems.org/92707www.nafems.org/92707

W biW bi WebinarsWebinars New topic each month!New topic each month! MultiMulti--physics Simulation using Directly Coupledphysics Simulation using Directly Coupled--Field Element Field Element

T h lT h l O t b 18O t b 18thth t 2 ETt 2 ETTechnology Technology October 18October 18thth at 2pm ET.at 2pm ET. Recent webinars:Recent webinars: Simulation Process ManagementSimulation Process Management NWC07 PreviewNWC07 Preview NWC07 PreviewNWC07 Preview SimulationSimulation--supported Decision Makingsupported Decision Making Simulation Driven Design (SDD) FindingsSimulation Driven Design (SDD) Findings


For the latest information, please refer to the NAFEMS website: For the latest information, please refer to the NAFEMS website: http://www.nafems.org/regional/north_americahttp://www.nafems.org/regional/north_america

Methods and Technology for the Analysis of Composite Materials

Dale BerrySIMULIA

Copyright 2007 Dassault Systmes

6Agenda

Industry trends

Recent development in Abaqus driven by the composites communityp q y p y

Copyright 2007 Dassault SystmesMethods and Technology for the Analysis of Composite Materials

7Composites Usage is Increasing in All Industries

Aerospace Boeing 787 1st large jet with a majority of composites by weight

Airbus 350WX - Over 60% of airframe made of new materials

UAVs primarily composite construction

Automotive Automotive F1 racing composite shells

Pickup truck composite box

Civil Composite-wrapped

bridge structures

Dentistry Fiber-reinforced composite dental bridges


8Increased Usage of Composites Means More Users Which Results in More Software Development EffortsWhich Results in More Software Development Efforts

More customers using software results in more requests for features and enhancements related to compositesp

Using composites in new applications requires new methods and technology developed to simulate those applicationstechnology developed to simulate those applications

Majority of development efforts are in response to and with guidance from customersfrom customers

Industry requirements

Bug reports

Enhancement requests

User groups

Benchmarks / round robins


Benchmarks / round robins

9Increase in Usage of Composites Corresponds to Expanded User BaseExpanded User Base

Composite analysis moving from the researcher level to the designer level requires:q

Enhanced usability features

Increased robustness

a

t

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n

Early Adopters

Researchers

n

s

o

p

h

i

s

t

i

c

a

S

i

m

u

l

a

t

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Copyright 2007 Dassault SystmesMethods and Technology for the Analysis of Composite Materials User sophistication

Analyst/Expert

EngineerDesigner

10

Increase in Usage of Composites Requires Development of New Software TechnologyDevelopment of New Software Technology

Composites are increasingly being used for load-bearing, critical parts Requires more reliability and capability in the software for simulating Requires more reliability and capability in the software for simulating

failure modes of composites

Fracture and failure

D l i ti

from McCarthy, M.A., Harte, CG, Wiggenraad, J.F.M., Michielsen, A.L.P.J., Kohlgruber, D., and Kamoulakos, A., Finite Element

Modeling of Crash Response of Composite Aerospace Sub-floor Delamination

Crashworthiness

Fatigue

g p p pStructures, Computational Mechanics, 26(3), Sept. 2000


11

Growth of Industry Drives Software DevelopmentIn Turn, Software Enables Industry GrowthIn Turn, Software Enables Industry Growth

Composites industry helps drive software developments More customers results in more requirements

L b i i i d bili Larger user base requires in increased usability

Increased usage requires greater reliability

New software developments enable growth of composites industryE f f t ll t t th t h l Ease of use features allow greater access to the technology

Increased capabilities provides greater confidence in simulation


12

Software Usability Enables Greater Number of Users

Expanded access to composites simulation through CAD interface / environment for composites definition

Direct interfaces between CAD lay-up and FEA lay-ups for simulation

Easier definition of composite layups

Enhanced post processing of composites for easier understanding of Enhanced post-processing of composites for easier understanding of results


13Greater Confidence in Simulation Enables Increased use of Composites for Critical Componentsp p

New, advanced technology provides for greater confidence in results Ability to simulate the many failure mechanisms of composites allows

composites to be used for critical parts Testing still necessary for validation, but simulation critical for

designing components


Example of high speed impact damage

14

Growth of Composites Industry and Increased Software Capabilities are CoupledIncreased Software Capabilities are Coupled

Broader use of composites requires advanced features

More users results in more requirements

Industry

SoftwareEnhanced usability results in more users

Advanced capabilities enables broader use of composites


15

Trend Charts

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/CAE Composites

Reducing Costs in Aircraft, Martin and Evans, Journal JOM, 52 (3) (2000), pp. 24-28.

p

o

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t

e

s

F

eManager Ply-based post-

processing Thru-thickness

plots Cohesive

C

o

m

plots Draping analysis Ply stack plots

elements Delamination

failure analysis Import of damage

t t (Std E )

VCCT analysis Continuum shells /CAE supports

lamina mat. props.


Abaqus versionv6.4 v6.5 v6.6 v6.7

state (Std. Exp.)p p

16

Good Software Capabilities Have Been Created, But There is Still A Lot of Work to Be DoneThere is Still A Lot of Work to Be Done

Current simulation methodology is not up to the task Verification of composites relies on testing p g

Expensive, time consuming

Current methodology has not evolved since the 1980s

T i l i l ti li th d t ti t fi t f il Typical simulation uses linear methods to estimate first failure

Current composites interfaces are not up to the task It is very time consuming to define composites and post-process

composites in today's CAE tools

Some CAD/CAE/PLM packages do not support progressive failure, delamination, or material damage

With linear methods, design margins for composite parts today are often too high the part is too expensive and heavy as a result

This reduces the value of the use of composites and blunts the cost


padvantages that composites can provide to a product

17

Agenda

Industry trends

Recent development in Abaqus driven by the composites communityp q y p y


18

End Result of Increased Composites Usage in Industry is a Composites Focus at SIMULIAIndustry is a Composites Focus at SIMULIA

SIMULIA Composites Mission StatementOur solution allows customers to:Our solution allows customers to:

Perform advanced composites simulations including static and dynamic analysis that includes linear, nonlinear, and damage / fracture /failure within a single environment

Predict the stiffness, first-failure, strength, and post-failure behavior at the component and full-vehicle structural scale of complex composite productsproducts

Simulate low- (from tool drop or hail), medium- (from runway debris), or high-velocity (ballistic penetration) events including Barely Visible Impact Damage (BVID) and Bird StrikeDamage (BVID) and Bird Strike

Have the very best in composite modeling, visualization, and post-processing through /CAE's new ply-based interfaces


p g g p y

19

A Look at Abaqus Developments that Enable Composite Usage in IndustryComposite Usage in Industry

SIMULIA technology needs to:gy Provide a platform for evolving your composites simulation

methodology to deliver more accurate results to meet regulatory and competitive demands

Be built in cooperation with and with guidance from customers and composite industry groups

Builds upon the traditional deep FEA simulation foundation of ABAQUSBuilds upon the traditional deep FEA simulation foundation of ABAQUS

Increase your composite simulation efficiency by reducing the time needed to generate composites models

Be backed by a solid experienced team of application engineers that will Be backed by a solid experienced team of application engineers that will help speed deployment to maximize the value of your investment in ABAQUS simulation


20

Abaqus Provides the Capability to Design Better Performing Composite ProductsBetter Performing Composite Products Technology Need:

Provide a platform for evolving composites simulation methodology to deliver more accurate results to meet regulatory and competitive demandsmore accurate results to meet regulatory and competitive demands

Meaning: To design better performing composite components, you need to change your

methodology Abaqus enables new analysis methodologymethodology. Abaqus enables new analysis methodology

New methodologies used by industry: VCCT for composite crack growth

B i H k d H il d Boeing, Hawker deHaviland Progressive failure analysis

NASA Glenn Research CenterM d lli Fib M t l L i t Modelling Fibre Metal Laminates

Airbus Deutschland, Advanced Lightweight Engineering


21

New Abaqus Developments are Focused-on and Driven-by Real Life Needsand Driven-by Real Life Needs

Technology Need : Be built in cooperation with and with guidance from customers and

composite industry groups

Meaning: Our new technologies are exactly what is needed to solve real problems, g y p ,

because it has been developed with cooperation with industry

Developments drive-by: Boeing VCCT collaborationBoeing VCCT collaboration

FAA Center of Excellence for Composite Materials

ASTM/D30, Composites Workshops and CMH-17

Fracture CRTFracture Customer Review Team


22

Along with Composites, Abaqus is a Leader in General Purpose FEA SimulationGeneral Purpose FEA Simulation

Technology Need : Builds upon the traditional deep FEA simulation foundation of Abaqus

Meaning: We are not offering solely a composites solution. Abaqus is a complete,

market leading FEA toolkit.g

Abaqus is used throughout the following industries: Aerospace & defense

A hit t & t ti Architecture & construction

Automotive

Consumer goods

Industrial equipment

Life sciences

Process power & petroleum


Process, power, & petroleum

Shipbuilding

23

New Composites Interface Reduces Time Spent Building Models Spent Building Models

Technology Need : Increases your composite simulation efficiency by reducing the time

needed to generate composites models

Meaning: The new ply-based modeling in /CAE saves a significant amount of time p y g g

in creating and understanding results for composite simulations

Time Savings: New interface reduces time spent creating composite models fromNew interface reduces time spent creating composite models from

multiple hours to less than one hour

New post-processing functionality dramatically reduces the amount of time yneed to interpret and understand results


24

Realize Abaqus Benefits Quickly Through Support by Abaqus Application EngineersSupport by Abaqus Application Engineers

Technology Need : Be backed by a solid experienced team of application engineers that will

help speed deployment to maximize the value of your investment in Abaqus simulation

Meaning: Methods evolution can be scary, we can help you with the process

Abaqus provides a range of services to support deployment: Assessment of needsAssessment of needs

Delivery of introductory and advanced training

Development, documentation and deployment ofmethods and proceduresmethods and procedures

On-site mentoring

Development of process automation solutions


25

Status Summary

Large-scale high-volume applications of composites is increasing Software developments to enable Realistic Simulation of composites

are appearing in COTS products This feeds even more industry applications...

Current demands driving the software community are: Increased efficiency in crack-propagation/damage simulation

C it f hi h l E M t li ti Composites for high-volume Energy Management applications

Fatigue lifecycle simulation

Repair modeling and residual life simulation

Accounting for the effects of aging

We will respond positively to these trends stay tuned!


We will respond positively to these trends...stay tuned!

F il Si l ti f Z i dFailure Simulation of Z-pinned Composites

Kyle C. IndermuehleATA Engineering

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Simulation of Z-Pinned Composites

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

One weakness of composites is low resistance to delamination Only matrix provides strength in thru-thickness

Z-Pinning addresses this by adding Trans-Laminar Reinforcements (TLR) Z-pins are a discontinuous fibres that are added

in the thru-thickness direction Z-pinning results in dramatically improved

delamination capabilities

Challenge is to accurately represent z-pins in analytical simulations Currently, testing is relied upon

www.ata-e.com

(Image courtesy of Chang, et. al. [2])

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Agenda. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Problem statement Abaqus technology utilized Simulation results and conclusions

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Problem Statement: Predict the Load Carrying

Capability of DCB Coupon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Can the z-pins resist the growth of the initial crack? Speciman 9 long by 1 wide by 0.12 thick 24 zero degree (0) plys 1 initial crack 1 unreinforced composite 1 z-pinsp p

www.ata-e.com

Freels, Jason K., Modelling Fracture in Z-pinned Composite Co-Cured Laminates Using Smeared Properties and Cohesive Elements in DYNA3D, Air Force Institute of Technology, AFIT/GMS/ENY/06-S01, 2006.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Agenda. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .New Abaqus Technology Enables Advanced Simulation of Composites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ABAQUS recently released a VCCT capability for analyzing compositesfor analyzing composites Partnership with Boeing Commercial Aircraft

Group to implement VCCT into Abaqus products

B d Li El ti F t Based on Linear Elastic Fracture Mechanics (LEFM) concepts

Based on computing the energy release rates for normal and shear crack-tip deformation modes

Compare energy release rates to interlaminar fracture toughness

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .VCCT-for-Abaqus Usage and Keywords. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Abaqus approach is surface based Extension of DEBOND Automatic modeling of post failure contact

Delamination plane paved

*CONTACT PAIR, INTERACTION=FRACTURE, ADJUST=NsetbondSlave--Slave surface name

with surface based contact pair

Slave Slave surface name Master--Master surface name

*SURFACE INTERACTION, NAME=FRACTURE, UCRACK, DEPVAR=12, PROPERTIES=16,

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,G_IC,G_IIC,G_IIIC,mixType,m,n,ow,

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Surface Interaction Properties Define Fracture Mechanics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Properties (given on data line)

G_ICG_IIC = Fracture toughness, modes I, II, and IIIG_IIIC

= 1 for B-K (2D shown):mixType ( )

m

III

IICICIICIC GG

GGGG

++

= 2 for Power law:o

IIIC

III

n

IIC

II

m

IC

I

GG

GG

GG

+

+

eta = Coefficient for B-K law

m, n, o = Exponents for mode mixity formula

IIICIICIC

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w = Out-of-plane width for 2D analysis

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Advantages of Abaqus VCCT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Runs during an ABAQUS analysis Utilizes the existing debond contact

architecture in ABAQUS/Standard,suitably extended

Does not utilize overlapped userelements as the basis for theimplementation

Does not require matched meshesacross bonded surfaces

Includes post-failure ramp-down ofcrack tip force

Includes post-failure penetration prevention Includes post-processing capabilities within Abaqus/Viewer Includes analysis stabilization algorithms to help stabilize running cracks in

Abaqus/Standard Is compatible with existing Abaqus elements and material, incrementation and

convergence controls, and stress-based procedures

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Along with VCCT, Abaqus Also Recently Released Cohesive Elements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Cohesive elements model progressive failure atCohesive elements model progressive failure at interfaces Adhesive joints with finite thickness

Constitutive modeling based on any ABAQUS g y Qmaterial

Enables failure modeling in ABAQUS/Explicit consistent with general framework

Delamination (adhesive layer of zero thickness) Delamination (adhesive layer of zero thickness) Based on a traction separation description for

delamination Enables failure modeling consistent with g

general framework

Damage initiation criteria Damage evolution criteria

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Delamination with Cohesive Elements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Delamination applications Traction separation law

T i ll h t i d b k

TN

Typically characterized by peak strength (N) and fracture energy (GTC)

Mode dependent

TCG

Mode dependent Linear elasticity with damage

Available in both ABAQUS/Standard and ABAQUS/Explicit 7

Typical traction-separation response

Q / p Modeling of damage under the

general framework used for other material models in ABAQUS

Damage initiation 34

5

6

7

G

T

C

Normal mode

Shear mode

Damage initiation Traction or separation-

based criterion Damage evolution Removal of elements

0

1

2

0 0.2 0.4 0.6 0.8 1

M d Mi

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Removal of elements Mode MixDependence of fracture toughness on mode mix

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cohesive Elements in Action. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

*element, type=coh2d4, elset=coh999999, 2005, 2105, 2106, 2006

*cohesive section, elset=coh, material=mat1, response=traction separation, controls=cont

*material, name=mat1*elastic, type=traction1.5e4, 1.5e4, 1.5e4

*damage initiation, criterion=maxe0 06 0 060.06, 0.06

*damage evolution, type=displacement, SOFTENING=EXPONENTIAL0.06, 0.06

*section controls, name=cont, element deletion=yes, max degradation=1.0

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Agenda. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


www.ata-e.com

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Proposed Method for Simulating Z-Pinned Composites Using Abaqus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Methodology Methodology Coupled VCCT and cohesive element

modelingC it f t t d i VCCT Composite fracture represented using VCCT

Based on GI, GII, GIII property definitions

Effect of Z-pins represented using cohesive elementselements

Cohesive element properties tuned based on test data

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Double Cantilever Beam (DCB). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

VCCT defined along entire beamC h i l t d fi d l i i d Cohesive elements defined only in z-pinned region

region of cohesive elements

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VCCT *DEBOND surface

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .VCCT Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . .*CONTACT PAIR, INTERACTION=FRACT,ADJUST=BNODESBOT, TOP

*SURFACE INTERACTION, NAME=FRACT,ucrack, properties=11, depvar=131.0, ,,, ,,, ,,

** Fracture toughness:GIc = 1.425GIIc = 6.0GIIIc = 6.0

** B-K parameter:modeMixLaw=1eta=1.75

** mixed mode parameteram =0.001an=0.0ao=1.0

. . .

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cohesive Elements Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . .*element, type=coh2d4, elset=coh999999, 2005, 2105, 2106, 2006

*elgen, elset=coh999999, 10, 100, 1,

*cohesive section, elset=coh, material=mat1, response=traction separation, thickness=specified, controls=cont1.0, 1.0

*material, name=mat1*elastic, type=traction1.5e4, 1.5e4, 1.5e4

*d i i i i i i*damage initiation, criterion=maxe0.06, 0.06

*damage evolution, type=displacement, SOFTENING=EXPONENTIAL0.06, 0.06

* i l l d l i*section controls, name=cont, element deletion=yes, max degradation=1.0

. . .

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DCB Simulation (Without Z-Pins). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Analysis and test compare fairly well Test peak is between 70 and 145 lbf (depending on rate) Analysis peak is 78 lbf Shape compares well

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .DCB Simulation (With Z-Pins). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Analytical model VCCT properties remain same as previous model Added zero-thickness cohesive elements for z-pins

active zactive z--pinspins

Failed zFailed z--pinspins

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Failed zFailed z pinspins


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Analysis and test compare fairly well Stiffness slope through z-pin area matches Peak load of ~75 lbf in test compared to 80 lbf in simulation at COD of

0.7 inches in both test and analysis

ABAQUS Test

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Simulation of composites is still very challengingE i ll th f il d Especially the many failure modes

Accurate analysis of composites requires new y p qmethodologies and new FEA technologies

Simulation of z pinned reinforced composites was Simulation of z-pinned reinforced composites was presented using a combined VCCT and Cohesive element approach in Abaqus

DCB i i d DCB specimen examined Initial results show good comparison between test and analysis

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THE INTERNATIONAL ASSOCIATIONTHE INTERNATIONAL ASSOCIATIONFOR THE ENGINEERING ANALYSIS COMMUNITYFOR THE ENGINEERING ANALYSIS COMMUNITY

Q&A SessionQ&A Session

Using the Q&A tool, please submit any questions you may have for our panel.questions you may have for our panel.

THE INTERNATIONAL ASSOCIATIONTHE INTERNATIONAL ASSOCIATIONFOR THE ENGINEERING ANALYSIS COMMUNITYFOR THE ENGINEERING ANALYSIS COMMUNITY

Thank you!Thank you!

If you have any further questions, please refer them to me:refer them to me:

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