Damage in composites - Technische Universität München · Damage in composites: experiments and simulation LCC Symposium, 12 September 2014 . Group . Sponsors and collaborators

Silvestre T Pinho [email protected]

Damage in composites:

experiments and simulation

LCC Symposium, 12 September 2014

mailto:[email protected]

Group

Sponsors and collaborators

Test pyramid

Coupon

Full

AC

Sub-component

Component

Struct. detail

Virtual

testing

Unidirectional

Woven

Discontinuous

Conclusions

Outline

Unidirectional

Woven

Discontinuous

Conclusions

Outline

Damage Initiation

World-Wide Failure Exercise - II

0%

20%

40%

60%

80%

100%

Pin

ho

Ca

rrere

Wolf

Puck

Ha

nse

n

Tsai-H

a

Hu

an

g

Cuntz

e

Ha

shin

Rote

m

Bog

etti

Ch

riste

nsen

Perc

enta

ge s

co

re

Combined quantitative and qualitative assessment

based on blind predictions from Kaddour & Hinton, J. Composite Materials 2013 47: 925

Score C

Score A and B

Matrix cracking

Matrix cracking in LaRC

• Mohr-Coulomb

approach

• Follows work from

Puck et al (1998)

Pinho, Camanho, Davila, Robinson, Iannucci. NASATM 213530 (2005)

0

50

100

150

200

250

-800 -700 -600 -500 -400 -300 -200 -100 0 100

s1 = s2 = s3 (MPa)

t 12 (

MP

a)

Predictions, matrix cracking

Experimental

Experimental

Input data

Matrix cracking: validation

Pinho, Darvizeh, Robinson, Schuecker, Camanho. WWFE-II (2013)

h La02h La0202a

02a La02hLa02

Matrix cracking: size effects

Camanho, Davila, Pinho, Robinson, Iannucci. Composites Part A, 2006

composite

Kink bands

rock paper

1

23

2

m1

m2

3

Kink plane

3

Matrix fracture plane

m2

3

LaRC failure criteria

Pinho, Camanho, Davila, Robinson, Iannucci. NASATM 213530 (2005)

LaRC failure criteria

Pinho, Darvizeh, Robinson, Schuecker, Camanho. WWFE-II (2013)

Kink bands: sequence of events

Pimenta, Gutkin, Pinho, Robinson. Comp Sci Tech 69(7-8) 948-955 (2009)

Gutkin, Pinho, Robinson, Curtis. Mechanics of Materials 43(11) 730-739 (2011)

Kink bands: fibre failure

Pimenta, Gutkin, Pinho, Robinson. Comp Sci Tech 69(7-8) 948-955 (2009)

Gutkin, Pinho, Robinson, Curtis. Mechanics of Materials 43(11) 730-739 (2011)

sinusoid

al fibres

150

straight

fibres

Kink bands: simulation @

microscale

Pimenta, Gutkin, Pinho, Robinson. Comp Sci Tech 69 (7-8) 956-964 (2009)

0

1

2

3

4

5

6

7

0 25 50 75 100 125 150 175 200

v(L) [mm]

P [N/mm]

analytical numerical

numerical

(no stab)

Kink bands: analytical vs. FE

• Good agreement

P

P

M

M

t

t

x, u

y, v

Pimenta, Gutkin, Pinho, Robinson. Comp Sci Tech 69 (7-8) 956-964 (2009)

Not just fibre kinking

Gutkin, Pinho, Robinson, Curtis. Comp Sci Tech 70(8) 1223-1231 (2010)

Not just fibre kinking


Longitudinal compression and

shear

0

20

40

60

80

100

120

-1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 0

t12 (MPa)

s1 (MPa)

Soden et al (1994)

Transition compressive shear failure to kinking

Inputs model


Deterministic predictions

fft : Fibre Tensile Failure

fmat : Matrix Failure

fsplit : Fibre Splitting Failure

fkink : Fibre Kinking Failure

fft : Fibre Tensile Failure

fmat : Matrix Failure

fsplit : Fibre Splitting Failure

fkink : Fibre Kinking Failure

Stochastic analyses

Whiteside, Pinho. Reliability Engineering & System Safety 108 1-9 (2012)

Damage propagation

Translaminar toughness

Pinho, Robinson, Iannucci. Comp Sci Tech 66(13) 2069-2079 (2006)


0

20

40

60

80

100

120

140

Baselin

e

Half

in-p

lane

Tw

ice

in-p

lane

More

90°

plie

s

Tw

ice

th

ick

Fracture toughness of 0° plies


0

20

40

60

80

100

120

140

Baselin

e

Half

in-p

lane

Tw

ice

in-p

lane

More

90°

plie

s

Tw

ice

th

ick

Blo

cked

0°

plie

s

Fracture toughness of 0° plies

Hierarchical fracture surface



level–[0] bundle

level–[1] bundle

level–[2] bundle

Numerical predictions

Open Hole Tension

IM7-8552 with QI lay-up

Gutkin, Pinho. ICCM-18, Jeju, Korea (2011)

Open Hole Compression

Delamination Splitting Matrix damage

Experiment: 424 MPa ± 45 MPa

Predicted : 451 MPa

Lee and Soutis (2008) 1

2

Gutkin, Pinho, ICCM-18, Jeju, Korea (2011)

Unidirectional

Woven

Discontinuous

Conclusions

Outline

UC for 2D woven composites

UC for 3D woven composites

Unit Cell Periodic BC Homogenised

Response

A knot and a Mobius strip

a) b) c)

Potter, Pinho, Robinson, et al Comput Mater Sci 51(1) 103-1011 (2012)


Response

3D woven composites

Potter, Pinho, Robinson, et al Comput Mater Sci 51(1) 103-1011 (2012)


Response

Reduced Unit Cells

Carvalho, Pinho, Robinson. Comp Sci Tech 71(7) 969-979 (2011)


Response

Reduced Unit Cells

dx

uxuxu

= )()( BA



Response

Exploiting symmetry

EoAA ˆ)()(

ˆ

Txx

uxTuxu

=

1 0 0

1 1 0

0 0 1 1 0 0

0 1 1

0 0 1 E

Ê

EO ˆx

Â

A

EOx



Response

Accurate stress fields

Tows Matrix

Tows

Carvalho, Pinho, Robinson. Composites Part A, 43 (8), 1326-1337 (2012)

Failure envelope generation

Biaxial Loading

-800

-600

-400

-200

0

200

400

600

800

-800 -400 0 400 800

Average

Experiments

IP

OP

Tensile

Failure

Compressive

Failure

σ1

[MPa]

σ2

[MPa]

Carvalho, Pinho, Robinson. Composites Part A, 43 (8), 1326-1337 (2012)

Braided Composites

Wehrkamp-Richter et al, ECCM, Seville, Spain, 2014

rUC

uncompacted rUC compacted

Analytical model for woven

Model Details

Carvalho, Pinho, Robinson. Composite Structures 94 (9), 2724-2735 (2012)


P

V

dxdx

dVV

Pdx

dx

dMM

M

p

t

t

xwT

dx

towt

Model Details

Equilibrium of a beam



LA

x

w0

y

LB

y×y Twill

LA

Model Details


Which represents a

reduced Unit Cell



LA

x

w0

y

LB

y×y Twill

LA

Model Details


Which represents a reduced

Unit Cell

Loaded Axially



Model Details



Unit Cell

Loaded Axially

With an elastic foundation

due to:



Model Details



Unit Cell

Loaded Axially


due to:

Adjacent Tows



DeformedUndeformed

θ

h

dx

dw

dw

dw

du

towt

DeformedUndeformed

dw

w

Both dwhBot 2

dx

w

towt

dwhTop 2Toph

Model Details



Unit Cell

Loaded Axially


due to:

Adjacent Tows

Adjacent plies



Model Details



Unit Cell

Loaded Axially


due to:

Adjacent Tows

Adjacent plies

Failure Criteria



y

x

-50

0

50

100

0 0.2 0.4 0.6 0.8 1

σ12

[MPa]

x/L

Analytical

Numerical



570 562 544

0

100

200

300

400

500

600

700

Analytical Numerical Experimental

Tension

-529 -550 -564

-700

-600

-500

-400

-300

-200

-100

0

Analytical Numerical Experimental

Compression

σ1

[MPa]

σ1

[MPa]


Unidirectional

Woven

Discontinous

Conclusions

Outline

rCFRP and Discontinuous Carbon

Systems

0

25

50

75

100

2009 2012 2015 2018

CF use (1000 ton/year)

Acmite Market Intelligence

0.5 mm 0.5 mm 0.5 mm

A B C

Architecture

• Different degrees of bundling

Pimenta, Pinho, Robinson, Wong, Pickering. Comp Sci Tech 70(2) 1713-25 (2011)

Toughening mechanisms

• Compact tension

testing

• Fractography

Optical microscopy

SEM analysis


0

2

4

6

0 5 10 15 20

CT tests

• Fracture toughness vs. fracture surface

A

Crack extension (mm)


Failure of bundles

• Bundle pull-out • Single-fibre pull-out

Self similar


500 μm

Failure of bundles

• Defibrillation

Hierarchic

al

failure

100 μm 50 μm


0

2

4

6

8

0 5 10 15 20 25 30 35

CT tests


B



0

10

20

30

0 5 10 15 20 25 30 35

CT tests


C



0

10

20

30

0 10 20 30 40 50 60 70

Fracture toughness

• Comparison


A

B

C Bundles

Toughness


0

10

20

30

0 10 20 30 40 50 60 70

Modelling

• Experimental vs. Analytical


A

B

C

Pimenta, Pinho, Robinson. ICCM-18, Jeju, Korea (2011)


level–[0] bundle

level–[1] bundle

level–[2] bundle

Unidirectional

Woven

Discontinuous

Conclusions

Outline

Conclusions

• Mechanical response of composites:

– There is a lot we still don’t know,

– but there is a lot we have learnt

• Modelling of mechanical response:

– Increasing use for design

– Potential for integration with manufacturing

– Potential for innovative microstructure design

Silvestre T Pinho [email protected]

Damage in composites:

experiments and simulation

LCC Symposium, 12 September 2014

mailto:[email protected]

Documents

Damage in composites - Technische Universität München · Damage in composites: experiments and simulation LCC Symposium, 12 September 2014 . Group . Sponsors and collaborators