Simulation of Delamination in Composites - DE - … in composites is a frequent failure mode because of the weak ... for applying cohesvie models to damgae behaviour of engineering

05.03.2015, pF www.pccl.at

P. Fuchs1), S. Stelzer 2), K. Fellner1), H. Pothukuchi1), G. Pinter 2)

1) Polymer Competence Center Leoben GmbH

2) Lehrstuhl für Werkstoffprüfung und Prüfung der Kunststoffe, Montanuniversität Leoben

Polyregion Leoben - 24th of March 2015

Simulation of Delamination in Composites

05.03.2015, pF www.pccl.at 2

- Introduction and Motivation

- Methods Simulation of Delamination

Cohesive Zone Model

Mixed Mode

Implementation in FEM

- Determination Model Parameters State of the Art

Fracture Tests

Numerical Optimization

- Application Examples Joining

Printed Circuit Boards

Cyclic Delamination

- Summary

Outline


Delamination in composites is a frequent failure mode because of the weak

interface between the layers

Occurrence in all phases (production,

transport, assembling, application)

of the composite lifetime

Possible trigger:

- Stresses trough curing shrinkage

- Temperature and humidity

- Impact loads

- Curved structures

- Stiffness jumps (e.g..: joining element)

3

Introduction and Motivation


4

Introduction and Motivation

Albert Turon Travesa, “Simulation of delamination in composites under quasi-static

and fatigue loading using cohesive zone models”.

Surface Internal

fracture mode

Impact

critical loads (Examples)

constraint transversal strain

Curved structures

Lehrstuhl für Kontinuumsmechanik und

Materialtheorie, Prof. W.H. Müller,

Technische Universität Berlin

Damage

05.03.2015, pF www.pccl.at 5

Fracture Mechanis Damage Mechanics

Methods

Simulation of Delamination

‘Virtual Crack Closure Technique’ (VCCT)

Qelle : Schwalbe K H, Scheider I, Cornec A; SIAM CM 09 – The SIAM method for applying cohesvie models to damgae behaviour of engineering materials and structures, GKSS

Cohesive Zone Model

Albert Turon Travesa, “Simulation of delamination in composites under quasi-static and fatigue

loading using cohesive zone models”.

Anderson, T.L. (2005), Fracture mechanics: Fundamentals and applications, 3rd ed., Taylor &

Francis, Boca Raton, FL.


Simulation Schädigung

Methods

Cohesive Zone Model

𝛿𝑚0

𝑇

𝛿𝑚𝑓

𝐺𝑐

𝑡 𝑡 + 𝛿𝑚0 𝑡 + 𝛿𝑚𝑓

𝐷𝑎𝑚𝑎𝑔𝑒 𝑖𝑛𝑖𝑡𝑎𝑡𝑖𝑜𝑛 𝑎𝑛𝑑 𝑒𝑣𝑜𝑙𝑢𝑡𝑖𝑜𝑛

𝑇𝑟𝑎𝑐𝑡𝑖𝑜𝑛

𝑠𝑒𝑝𝑒𝑟𝑎𝑡𝑖𝑜𝑛

modeling possibilities

05.03.2015, pF www.pccl.at 7

effective displacement unified potential

Methods

‚Mixed Mode‘

Khoramishad, H., Crocombe, A.D., Katnam, K.B. and Ashcroft, I.A. (2010), “Predicting

fatigue damage in adhesively bonded joints using a cohesive zone model”, International

Journal of Fatigue, Vol. 32 No. 7, pp. 1146–1158.

Park, K., Paulino, G.H. and Roesler, J.R. (2009), “A unified potential-based cohesive model of

mixed-mode fracture”, Journal of the Mechanics and Physics of Solids, Vol. 57 No. 6, pp. 891–

908.

Modeling of combined fracture

modes

05.03.2015, pF www.pccl.at 8

Contact Property

Methods

Implementation in FEM

Quelle: Zhen-zhong Du, Dassault Systèmes Simulia Corp.

Cohesive Elements

X-FEM

‚eXtendend Finite Elemente Method‘

Feih, S., “Modelling cohesive laws in finite element simulations via an adapted contact procedure”.

Qelle : Schwalbe K H, Scheider I, Cornec A; SIAM CM 09 – The SIAM method for applying cohesvie models to damgae behaviour of engineering materials and structures, GKSS


Possible Methods for the Parameter Determination

Determination Model Parameters

State of the Art

Schwalbe K H, Scheider I, Cornec A; SIAM CM 09 – The SIAM method for applying cohesvie models to damgae behaviour of engineering materials and structures, GKSS

0 0.1 0.2 0.3 0.40

5

10

15

20

[mm]

J [

kJm

-2]

0 0,05 0,1 0,15 0,2 0,3 0,3 0,35 0,4

0

100

200

300

400

500

[mm]

[

MP

a]

)()(

J

dSx

unWdxJ i

jij

1

2

Direct Measurement J-Integral Method Numerical Optimization

Fuchs, P.F., Major, Z. and Lang, R.W. (2009), “Characterization of the failure

behavior of printed circuit boards under dynamic loading conditions”, 12th

International Conference on Fracture 2009, ICF-12, No. 7, pp. 5441–5449.

0 10 20 30 40 50 600

10

20

30

40

50

60

70

Displacement s, mm

Fo

rce

F

, N

Simulation

Measurement

0.5 MPa

1.25 MPa

5 MPa

Fuchs, P.F., Pinter, G. and Fellner, K. (2013), “Local damage

simulations of printed circuit boards based on in-plane

cohesive zone parameters”, Circuit World, Vol. 39 No. 2, pp.

60–66.

05.03.2015, pF www.pccl.at 10

Experiments as basis for the numerical optimization


Fracture Tests

DCB ENF FRMM

Double Canitlever Beam

(Mode I Versuch) End Notched Flexure

(Mode II Versuch) Fixed Ratio Mixed Mode

(Mixed Mode Versuch)


‚Double Cantilever Beam‘

Mode I Versuch



DCB

Albert Turon Travesa, “Simulation of delamination in composites under quasi-static and fatigue

loading using cohesive zone models”.

parameters:

• stiffness

• critical energy release rate

• definition damage initiation (e.g. stress or

displacement)

• damage evolution (e.g.: linear, bilinear or

exponential)

• element size


parameters:

• stiffness

• critical energy release rate

• definition damage initiation (e.g. stress or

displacement)

• damage evolution (e.g.: linear, bilinear or

exponential)

• element size

• time step

• friction interface

• friction bearings

‚End Notched Flexure‘

Mode II Test



ENF


Motivation

Application Examples

Joining Techniques

Cold metal transfer (CMT) welding head attached to three axes moving portal

Mould with fixed metall inserts

CMT-pins for reinforcing CFRP to CFRP joints (stainless steel or titanium)

Specimen Preperation

‚Single Lap Shear Test‘

Optimized experimental methods for the description of the delamination and failure behavior of

high performance composites and joints, 2014


Determination Paratmeters CZM


Joining Techniques

FRMM 0 10 MPa

t0 70 MPa

GI 0.405 N/m

GII 1.005 N/m

h 2.64

damage evolution: linear

damage initation : maximum stress

Mixed Mode: BK


Single Lap Shear Simulation


Joining Techniques

• Damage evolution

• Influende fracuture

modes

1

2 3

1 2

3


Results


Joining Techniques

pin array 1

pin array 2

pin array 3

05.03.2015, pF www.pccl.at 17

Multilayer built-ups

Interaction of materials with significantly different thermo mechanical behavior

Wide field of applications – various loading conditions

Temperature Vibrations Impact

Fatigue



Motivation

05.03.2015, pF www.pccl.at 18



Fuchs, P. and Major, Z. (2011), “Cyclic bend tests for the reliability evaluation of printed

circuit boards under dynamic loads”, Frattura ed Integrità Strutturale No. 15, pp. 64–73.

Fuchs, P.F., Pinter, G. and Krivec, T., “Design independent lifetime assessment method for

PCBs under low cycle fatigue loading conditions”, EuroSimE, Vol. 2014.

Loading and Failure Modes

05.03.2015, pF www.pccl.at 19 Quelle: Schürmann H, Konstruieren mit Faser-Kunststoff-Verbunden, Springer, 2007

Materials

fibreglass reinforced epoxy laminates

glas fibre fabric with differences in

warp and weft direction

very thin (50-200 mm)

orthotropic material behaviour



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E11,E22,(E33)

n12, (n13, n23)

G12,(G13,G23)

Engineering Constants

Determination of the in plane engineering constants 1122122224522114

22114512

EEEEEE

EEEG

n

0 0.02 0.040

50

100

150

200

250

strain , -

str

ess

, M

Pa

0°

90°

45°

0 1 2 3 4

0

5

10

x 10-3

time t, -str

ain

,

-

transversal strain

longitudinal strain

05.03.2015, pF www.pccl.at 21



0 10 20 30 40 50 600

10

20

30

40

50

60

70

Displacement s, mm

Fo

rce

F

, N

Simulation

Measurement

0.5 MPa

1.25 MPa

5 MPa

Adaption cohesive stress

Determination of the damage initiation

Fuchs, P. and Major, Z. (2011), “Cyclic bend tests for the reliability evaluation of printed circuit boards under

dynamic loads”, Frattura ed Integrità Strutturale No. 15, pp. 64–73.

05.03.2015, pF www.pccl.at 22



0 50 100 150 2000

10

20

30

40

50

60

Displacement s, mm

Fo

rce

F

, N

Simulation

Measurement

2 mm Probe

5 mm Probe

0.7 mm Probe

Evaluation of the cohesive zone model

Determination of the damage initiation


23



Model

05.03.2015, pF www.pccl.at 24

Sub Model

Cross Section 3D Model

Simulation model



Elements: ~ 120 000 Computation time: ~ 1Std (8 CPUs)

Elements: ~ 200 000 Computation time: ~ 24 Std (8 CPUs)




Sub Model SubSub Model

Displacement SubSub Model

Regarded Local Area

Mises Stress Sub Model

Fracture Simulation

25

To simulate the local damage behavior a

‘subsubmodel’ was created

The modeling space was reduced to 2D to

reduce the model size and the computing

time

0 0.02 0.04 0.06 0.08-2

-1.8

-1.6

-1.4

-1.2x 10

-3

edge length s, mmx-d

ispla

cm

en

t

xs,

mm

0 0.02 0.04 0.06 0.08

2.983

2.983

2.9831

edge length s, mmy-d

ispla

cm

en

t

xs,

mm

05.03.2015, pF www.pccl.at 26



X-FEM Simulation

Failure Mode experiment

Fracture simulation


Summary

Delamination is critical in a load of composite applications because e of

the weak interface between the layers

Possible simulation methods based on fracture and damage mechanics

The phenomenological cohesive Zone Model is advantageous with

respect to the application in a FEM simulation

Challenging Determination of the Cohesive Zone Model Parameters

Useful to understand and interpret delamination in order to optimize the

component design

05.03.2015, pF www.pccl.at 28

Acknowledgement

Die vorliegende Forschungsarbeit wurde an der Polymer Competence Center Leoben GmbH

im Rahmen des Kompetenzzentren-Programms COMET des Bundesministeriums für

Verkehr, Innovation und Technologie und des Bundesministeriums für Wirtschaft, Familie

und Jugend unter Beteiligung der Montanuniversität Leoben, der Austria Technologie &

Systemtechnik AG, AT&S und der Andritz Hydro AG durchgeführt und mit Mitteln des Bundes und

der Länder Steiermark, Niederösterreich und Oberösterreich gefördert.

Teile der Forschungsarbeit wurden weiters durch das FFG TAKE OFF Projekt

Composite+composite Joints with Enhanced damage toleranCe (CoJEC) gefördert.

Documents

Simulation of Delamination in Composites - DE - … in composites is a frequent failure mode because of the weak ... for applying cohesvie models to damgae behaviour of engineering