Textile Preforms for Composites - KU Leuven · 2014-12-20 · Yarn properties Ends/picks count Weave coding Yarn shapes Full description of the geometry Input Distance between the

1

1 1

Textile Preforms for Composites

1. Introduction

2. Fibres and yarns

3. Textiles in general

4. Fabrics: NCF – Woven – Braided – Knitted – 3D – Spaced

5. Modelling of textile composites

Stepan V. Lomov

Department MTM – KU Leuven

S.V. Lomov - Textile Preforms for Composites - 5. Modelling

2

Contents

1. Introduction

2. Geometrical models of textile reinforcement internal architecture

3. Models of textile reinforcement deformability

4. Models of textile reinforcement permeability

5. Mechanical properties of textile composites, damage

6. Conclusion: Models integration


2

3

1. Introduction







S.V. Lomov 27.07.2012

Textile composites: meso-scale as a bridge to Macro

x

z

p

h z(x)

Q

Q

d2

d1

Z

A

B

Internal architecture of the reinforcement

Deformation resistance and change of

geometry

Compr. Shear Tension Bending

Perme-

ability

M

R=1/

K

Drapeability and formability

Impregnation

Production

Mechanical properties

and damage

Performance

Structural analysis

4

4 S.V. Lomov - Textile Preforms for Composites - 5. Modelling 4

3

5

Мodels

Unit cell

Manufacturing

Pefomance


Deformation

resistance and

change of geometry

Permeability

Drapeability and

formability Impregnation

Mechanical

properties and

damage

Structural analysis

S.V. Lomov - Textile Preforms for Composites - 5. Modelling 5

6

Software

Unit cell

Manufacturing

Performance


Deformation

resistance and

change of geometry

Permeability

Drapeability and

formability Impregnation

Mechanical

properties and

damage

Structural analysis

WiseTex

TexGen

FlowTex

CFD

WiseTex

Abaqus

TexComp

Abaqus

ANSYS

PAM-RTM

LCM

RTM-Works

PAM-FORM

QuikForm

CoData

Abaqus

Nastran РАМ-SYSPLY

Abaqus PAM-CRASH

ANSYS


4

7

WiseTex software package: Virtual textiles and textile composites

• commercialised by K.U.Leuven R&D

• integrated in SYSPLY package of ESI Group

6 industrial licenses

30+ university licenses


Textile structures in WiseTex

Woven

Braided NCF

Laminates

Knitted


5

Smart composites

AE

sensor

on-board

computer

super-

computer

structural

health analysis

decision on

maintenance


10

1. Introduction


• A model of internal geometry of (2D or 3D) woven fabric

• From geometrical model to finite elements






6

Road map: Geometrical model of the (deformed) unit cell

Structure: weave / topology / interlacing

– contacts, relative positions

Geometry: Placement of the yarns inside

the (deformed) unit cell

– yarn paths / directions / twist

– yarn volumes / cross-sections

Deformations of the dry fabric:

compression, tension, shear, bending

FE mesh: Yarn volumes,

contacts

Textile mechanics

Textile mechanics

FE

“CAD”

Meshing












contacts

Textile mechanics

Textile mechanics

FE

“CAD”

Meshing


7

Woven fabric: Detailed road map

Weave model

Elementary bent intervals

Crimp height and yarn thickness

Yarn properties

Ends/picks count

Weave coding

Yarn shapes

Full description of the geometry

Input

Distance between the layers


Weave model: matrix coding

warp zones NWa

yarns in a warp zone NWaZ[iWa]

weft rows NWe

weft layers L

4

1 2 3

1 2 3 4 layer 1

layer 2

level 0

level 1

level 2

1210

0121

1012

2101warp 1

warp 2

warp 3

warp 4

1 2-1

2-2

2-3

3

4-1

4-2

4-3

0 4

1 1

2 2

3 3

4 0

1 1

2 2

3 3

1

2

3

4

warp zones

Weave

model

Elementary

bent intervals

Crimp,

yarn

thickness

Yarn

prop.

Ends /

picks

Weave

coding

Yarn shapes

Full

description of

the geometry

Input

Distance

between

layers


8

Elementary bent intervals

base weft yarns

elementary bent interval: warp

iWa

iWa,

iWaInt

iWe1 iWe2

Elementary bent interval iWaInt of warp yarn iWa

1. Numbers of base weft yarns iWe1, iWe2

2. Position of the yarn vis-à-vis the base pos1, pos2

pos2 = BELOW

pos1 = OVER

Weave

model

Elementary

bent intervals

Crimp,

yarn

thickness

Yarn

prop.

Ends /

picks

Weave

coding

Yarn shapes

Full

description of

the geometry

Input

Distance

between

layers


Yarn shape in a bent interval – 1

element e

eeee

sPBA

eeee

sPBA

BAsPW

sPBAW

eee

eee

,|minmin

;,min

)(,

,,

Problem B:

find the positions of the

ends of the bent interval

(crimp heights)

Problem A:

find the shape P(s) for the

given end positions

Weave

model

Elementary

bent intervals

Crimp,

yarn

thickness

Yarn

prop.

Ends /

picks

Weave

coding

Yarn shapes

Full

description of

the geometry

Input

Distance

between

layers


9

Yarn shape in a bent interval – 2

h_We

d11_We

d21_We

d12_We

d22_We base contour

p

d11_Wa h_Wa

• distance between base

contours: picks count

• dimensions: compression

resistance

• crimp height: equilibrium of

bending forces

0)(;2/)(;0)0(;2/)0(:)( pzhpzzhzxz

p

dxz

zBW

0

2/52

2

min12

1

p

xxxxx

p

hAxx

h

z

,

2

11164

2

1 2223

z(x)


Characteristic functions of bent intervals

h_We

d11_We

d21_We

d12_We

d22_We

p

d11_Wa h_Wa

0 0.2 0.4 0.6 0.8 10

1

2

3

4

5

6

h/p

A

F

h/p

p

hF

p

Bdx

z

zBW

p

0

2/52

2

12

1

p

hF

ph

B

h

WQ

22

p

hF

pdx

z

z

p

p1

1

1

0

2/52

2

energy

transversal force

average curvature

z(x)

main parameter:

h/p

main property

B(k)


10

Distance between the layers

)

,,,,,,(max

22

212111

,1,1,

1,1,2,1,1211,

1

We

jlk

We

jl

We

klj

We

lj

Wa

kj

We

klj

We

klj

We

jlk

We

jlk

We

jl

We

jltightkj

ll

PhPh

dddddshapeshapezZZ

level 1 level 2

pWe

shift of the

layers

Weave

model

Elementary

bent intervals

Crimp,

yarn

thickness

Yarn

prop.

Ends /

picks

Weave

coding

Yarn shapes

Full

description of

the geometry

Input

Distance

between

layers

weft j,l+1; interval k2

weft j,l; interval k1

hjlWe

hjl+1We

warp i z

Zl

Zl+1

x


Compressibility of the yarns

d1

d2

Q

5.0...3.0

12

10

22

10

11

;)(

)(

d

Qd

d

Qd

Weave

model

Elementary

bent intervals

Crimp,

yarn

thickness

Yarn

prop.

Ends /

picks

Weave

coding

Yarn shapes

Full

description of

the geometry

Input

Distance

between

layers


11

Crimp heights: minimum energy – 1

element e

eeee

sPBA

eeee

sPBA

BAsPW

sPBAW

eee

eee

,|minmin

;,min

)(,

,,

Problem B:

find the positions of the

ends of the bent interval

(crimp heights)

Problem A:

find the shape P(s) for the

given end positions

Weave

model

Elementary

bent intervals

Crimp,

yarn

thickness

Yarn

prop.

Ends /

picks

Weave

coding

Yarn shapes

Full

description of

the geometry

Input

Distance

between

layers


Crimp heights: minimum energy – 2

x

z

p

h z(x)

Q

Q

d2

d1

Z

A

B

warp i

warp crimp interval k

weft j’,l’

weft j’’,l’’

weft crimp interval k’

weft crimp interval k’’

min

,,,

kljWe

jlk

We

jl

We

jlk

We

jlk

We

jlk

kiWa

ik

Wa

ik

Wa

ik

Wa

ik

Wa

ik

p

hF

p

B

p

hF

p

BW

minimum energy:


12

Full system of equations

warp i

warp crimp interval k

weft j’,l’

weft j’’,l’’

weft crimp interval k’

weft crimp interval k’’

warps NWa

weft layers L

weft rows NWe

Unknown

variables

Number Equations

Dimensions of

warp and weft

yarns

Vertical positions

of mid-planes of

weft layers Zl

L

Weft crimp heights L*NWe

L

l

NWe

j

jlKNWeNWa1 1

2

We

jlh

1 10 1

2

...ij lWa Wa Wa

ik i i Wa

ik

Qd d

d

We

kjl

We

jl

We

jl

We

kjl

We

jl

We

kjl

We

jl

We

jl

We

kjl

We

jl

Wa

ki

Wa

ki

Wa

ki

Wa

ki

Wa

i

Wa

ki

Wa

ki

Wa

ki

Wa

ki

Wa

i

ijl

p

hF

hp

B

p

hF

hp

B

p

hF

hp

B

p

hF

hp

BQ

11

1

1

11

2

1

2

1

)

,,,,,,(max

22

212111

,1,1,

1,1,2,1,1211,

1

We

jlk

We

jl

We

klj

We

lj

Wa

kj

We

klj

We

klj

We

jlk

We

jlk

We

jl

We

jltightkj

ll

PhPh

dddddshapeshapezZZ

min

,,,

kljWe

jlk

We

jl

We

jlk

We

jlk

We

jlk

kiWa

ik

Wa

ik

Wa

ik

Wa

ik

Wa

ik

p

hF

p

B

p

hF

p

BW


The flowchart of the solution

hWelj=0

calculate Q for all contacts warp/weft

calculate d for all contacts warp/weft

calculate Zl

solve energy equation (l,j) for hWelj, all other

hWe given

max|hWelj- holdWe

lj|<prec

no

yes

h,%

0 2 4 6

5

10

15

iterations


13

Description of internal geometry

O

r(s)

X Y

Z

t

a1

a2

O

d2 d1

Each segment:

• direction

• curvature

• two dimensions

• average Vf

Unit cell:

dimensions X,Y,Z

number of yarns

Each yarn:

set of segments


Examples of calculations of internal geometry of 3D fabrics/composites

Glass 3D woven: X-ray µCT and simulated

Carbon/epoxy 3D woven: simulated and real cross-sections


14

Visualisation


28

1. Introduction


• A model of internal geometry of (2D or 3D) woven fabric

• From geometrical model to finite elements






15











contacts

Textile mechanics

Textile mechanics

FE

“CAD”

Meshing


A gallery of finite element models

3-axial braid

knitted

plain weave

3D woven

stitched

NCF S.V. Lomov - Textile Preforms for Composites - 5. Modelling 30

16

meso-FE: Road map

Geometric modeller

Geometry corrector

Meshing

Assign material

properties

Boundary conditions

FE solver,

postprocessor

Homogenisation

Damage analysis

N+1 N

N+2


meso-FE: Road map

Geometric modeller

Geometry corrector

Meshing

Assign material

properties

Boundary conditions

FE solver,

postprocessor

Homogenisation

Damage analysis

N+1 N

N+2


17

Yarn volumes

O

r(s)

X Y

Z

t

a1

a2

O

d2 d1

P f

Vf Fibre structure of

the yarns

Solid model

N+1 N

N+2

Orthotropy of the

impregnated yarns


Orthotropy of the impregnated yarns

2

1 3

f

mf

m

mf

t

f

E

EV

EEE

EVEVE

22

3322

1111

11

1

f

mf

m

f

mf

m

G

GV

GG

G

GV

GGG

23

23

12

1312

11

11

12

1

23

2223

121312

G

E

VV mf

f

f

Chamis model


18

Interpenetration of the volumes

no interpenetration

(rare) “vertical”

interpenetration

complex

interpenetration

The correction of the geometry should preserve:

• overall fibre volume fraction in the composite (dimensions of the unit cell and

amount of fibres in all the yarns)

• average fibre volume fraction in the yarns in realistic bounds (< 70…75%)


Manual correction

1

2

3

p0

1

p11

p0

2 p1

2

s1

s2

p0

1 p11 s1 s2

1

p01=p11

P02=p1

2

s1

s2

p01=p11

6 2 3 4 5

7

1

1. First interpenetration type 2. Second interpenetration type

3. Third interpenetration type

6 2 3 4 5

7

1

[1]


19

Interpenetration of the volumes: correction via inermediary FEA

z

- z

Deformation

Splitting

Separation


Example of the volume correction: 3-axial braid


20

Contact surfaces


Mesh interpolation

x

z y

sx sx

x

z y

320(MPa) 60(MPa)

fine mesh Global and local mesh


21

Voxels


42

1. Introduction







22

What is a forming simulation?

Given:

1. Preforms characterisation

2. Mould geometry

3. Mould temperature

4. Forming speed

Calculate:

1. Wrinkling

2. Waste

3. Local shear and other local parameters of the reinforcement


Optimise forming operation

1. Mould geometry (radii of curvature...)

2. Blank orientation

3. Configuration of a blank-holder and blank-holder tension

4. Forming temperature and evenness of the temperature distribution

5. Forming speed

main optimisation parameter: WRINKLING

[2]


23

Optimise impregnation

Permeability of textile depends on local volume fraction

and local shear

Local volume fraction and local shear depend on local

deformation

Local deformation depends on draping of the preform


Forming impregnation

The front is not round – the preform is

anisotropic

Distribution of shear angles local

permeability

shear angles

impregnation: PAM-RTM

images: ESI Group

Drape: PAM-QuikForm

front movement


24

Example

Constant permeability

Accounting for the preform deformation

images: ESI Group S.V. Lomov - Textile Preforms for Composites - 5. Modelling 47

Optimise performance

Stiffness of composite depends on local orientation of the fibres

Local orientation of the fibres depends on local deformation

Local deformation depends on draping of the preform


25

Forming structural analysis

WiseTex

Local deformation

parameters

(thickness, shear…)

Forming:

QUIKFORM

Internal

geometry

Local stiffness [Q]

FE analysis:

SYSPLY

Stress/strain fields

TexComp


Key result: Distribution of shear angle of the preform

locking

images: Kristof Vanclooster S.V. Lomov - Textile Preforms for Composites - 5. Modelling 50

26

Cloth draping

Well advanced simulations of garments

[3]


Principle of kinematic draping simulation

1. NO mechanical properties

2. DEPENDS on the initial choice of

principal directions [4]


27

Good predictions for symmetrical configurations...

warp parallel

to the

cylinder axis


… may be very bad for asymmetrical situations

warp at 45° to the cylinder

axis

assumed in kinematic draping

and real advancement of

draping


28

Finite element simulations of draping: Example – 1

[5]


Expicit FE solution

[5]


29

Stages of PAM-FORM analysis

[6]


Material model for textile fabrics – 1

shear diagram

viscous matrix

non-linear tension


30

Material model for textile fabrics – 2

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0 10 20 30 40 50

Shear angle, °

Sh

ear

forc

e,

N/m

m

0

50

100

150

200

250

300

0 0.2 0.4 0.6 0.8 1

EpsX, %

Fx

pe

r y

arn

, N

effective viscosity is

different from the

viscosity of the matrix

shear

tension

viscosity


Problems of kinematic draping solved!

kinematic draping PAM-FORM


31

WiseTex models of deformations of textiles

Compression

Uni-

and Biaxial tension

Shear

(un)bending + compression of yarns

work of compressive force Q on change of thickness db

= change of bending energy of yarns dW

d2Wa

d2We

q

d1Wa

d1We

Qij

T T

Q

hWa

p

• Friction between the yarns

• Lateral compression of the yarns

• (Un) bending of the yarns

• Torsion of the yarns

• Vertical displacement of the yarns T

T Q


FE modelling of deformations of textiles

images: Ph. Boisse

shear tension


32

63

1. Introduction







Simulation of impregnation

Input:

• mould geometry

• permeability of the textile

• resin viscosity

• positions of inlets and

vents

• pressure drop

Output:

• movement of the flow front

• dry spots

• impregnation time

pΚ

gradv

Darcy equation


33

Solution of Darcy equation

pΚ

gradv

Assumption:

front moves with velocity <v> =

ideal wetting

inlets

vents

front iso-chrones

Meyer et al 2004


Calculation of preform permeability

Geometry: Placement of the yarns inside the

(deformed) unit cell



“Voxels” Meshing

Voxel-mesh FE mech

(Navier-)

Stokes

solver

Fabric permeability

Analytical

“Hydraulic”


34

Darcy permeability: homogenised (Navier-) Stokes solution

p = 0

<u>

<u>

p = p u(A) - u(A´) = const(A)

AA´= periodic translation

A

A´

0 0

0 0

0 0

x

y

z

K

K

K

K


Geometrical models and voxel mesh

Reinforcement

model

Voxel model

woven, monofilaments quasi-UD woven, carbon

non-woven, glass NCF, carbon


35

(Navier-) Stokes solution

Requirements:

• Automated

• Fast and accurate

• Accurate in narrow channels

• Periodic boundary conditions

• Sheared unit cell

Implementation:

• Navier-Stokes:

(adapted) NaSt3d

staggered grid

• Stokes

collocated grid

stabilisation term

PETSc package, GMRES(m)

Navier-Stokes:

staggered grid,

difficulty with

isolated cells

F

S

F


Boundary conditions: faces of the unit cell and internal boundaries

wall and internal boundary Г

velocity

pressure (Stokes equation)

=> Re = 0.05


36

FlowTex: Integration with WiseTex and GUI


Experimental validation: Overview

Ky

Kx


37

Coupled meso-macro simulation

WiseTex

Local reinforcement

deformation Process model

Local reinforcement

geometry

Local permeability

[K]

Filling simulation

Processing

parameters

FlowTex

stand-alone

application


Necessary performance of mass-simulations

10,000 finite elements

or…

90 values of shear angles (0°, 1°, 2°…) and 5 degrees of compression =

= about 450 calculation variants

3h calculation time 2 s per fabric configuration

5 s


38

75

1. Introduction







Road map: Micromechanics of textile composites

Geometry: Placement of the yarns inside the (deformed) unit

cell



“Voxels” Meching

Voxel - partitioning FE mesh

FE

Stiffness

Orientation

averaging

Inclusions

Stress-strain fields, damage


39

Stiffness: Simple model neglecting yarn crimp

9090

00

90

0

900

900

PT

PT

h

h

hhh

VFVFVF

woven laminate UD laminate

two plies

representing warp

and weft

90°

0° h_0°

h_90° linear density of

warp/weft and

ends/picks count

Assumption: iso-strain

900 CCCh

h

h

h 900

Stiffness matrix Approximation: Young’s modulus

9090

00 E

h

hE

h

hE


Orientation averaging

The textile structure is subdivided into

elements; each element is represented

by a UD composite

CSi

GCS

Vi

N

i

i

N

i

iii

meff VVVGCSCSVGCSGCS11

;1 CCC

effective

stiffness of the

composite matrix stiffness

stiffness of

elements

Assumption: iso-strain


40


Example: 3D woven glass/epoxy composite

exp OA

E1, GPa 24.3±1.2 22.7

E2, GPa 25.1±2.34 22.8

E3, GPa n/a 10.1

G12, GPa n/a 3.38

ν12 0.141±0.071 0.109

ν13 n/a 0.377

ν23 n/a 0.380

E45º, GPa 12.9±0.5 10.7

G45º, GPa n/a 10.3

ν45º 0.502±0.21 0.581

Vf, % E1,GPa E2,E3,

GPa 12 , 13 23

G12, G13,

GPa G23, GPa

3D weave, warp 2275 tex 64.1 47.2 10.8 0.266 0.440 4.24 3.73

3D weave, warp 1100 tex 60.1 44.5 9.7 0.271 0.445 3.79 3.35

3D weave, Z 276 tex 78.0 56.8 16.7 0.252 0.414 6.73 5.9

3D weave, fill 1470 tex 59.1 43.7 9.44 0.272 0.447 3.69 3.26

W

F

Z W

Elastic properties of the impregnated yarns

Areal density, g/m2 3255

Thickness, mm 2.6

Ends, 1/cm 2.76

Picks. 1/cm 2.64

Z-yarns, 1/cm 2.76

VF, % 48.9

79

Method of Inclusions: Yarns as a collection of curved segments

[C]

The yarn segment is NOT circular,

but has two different diameters


41

81

Curved segment as an equivalent ellipsoidal inclusion

, 3.14b R

a a

R 2a

2b

1. Volume fraction of each equivalent

ellipsoid in the unit cell corresponds to

the volume fraction of the segment

which it represents.

2. The elongation of the equivalent

ellipsoid depends on the curvature of

the segment.

3. The stiffness of the ellipsoid inclusion

is equal to the homogenised local

stiffness in the segment.

4. For a non-circular yarn the ellipsoid

has all the three axis different

5. The equivalent ellipsoids are NOT a

physical substitution of the yarn

segments; they are merely

mathematical means to calculate the

stress-strain states in the segments,

using Eshelby tensors


Flowchart

Geometrical

preprocessor Textile data

Internal geometry of

textile and partitioning

into segments

Segment

processor

Matrix and

fibre data

Assembly of

equivalent ellipsoidal

inclusions

Mori – Tanaka

homogenisation

Homogenisation

on micro-level

Homogenised stiffness

of the composite


42

Software: WiseTex and TexComp (KULeuven)

Models of textile geometry

and deformability

Predictive

models of

composites

mechanics

Models of internal structure and

deformation of unit cell of textile

reinforcement:

• woven 2D and 3D

• braided bi- and triaxial

• knitted

Homogenisation of stiffness of textile

composite, based on the method of

inclusions:

any textile reinforcement described by

WiseTex, including deformed (sheared,

compressed, tensed)


Comparison

5.13 4.955.65

5.25 5.44

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

GE001_G GE002_G GE012_G

G

W iseTex/TexComp

Experim ent

glass/epoxy


43

Stiffness prediction: FE and inclusions

exp OA Inclusions FE @49.3

E1, GPa 24.3±1.2 22.7 24.2 23.6

E2, GPa 25.1±2.34 22.8 24.2 23.7

E3, GPa n/a 10.1 9.1 9.5

ν12 0.141±0.071 0.109 0.161 0.128

ν13 n/a 0.377 0.370 0.365

ν23 n/a 0.380 0.368 0.359

no real need in FE for the stiffness prediction

W

F

Z W


Road map: Micromechanics of textile composites

Geometry: Placement of the yarns inside the (deformed) unit

cell



“Voxels” Meching

Voxel - partitioning FE mesh

FE

Stiffness

Orientation

averaging

Inclusions

Stress-strain fields, damage


44

87

meso-FE: Road map

Geometric modeller

Geometry corrector

Meshing

Assign material

properties

Boundary conditions

FE solver,

postprocessor

Homogenisation

Damage analysis

N+1 N

N+2


88

Solving meso-FE problem

| |

( )

|

( )

|

Homogenised stiffness :

0;

1

2

1 1

ijkl kpq l j

ipq ipq q ip p iq

pq

ij ijkl kpq l

kl

ijkl ijpq pkl q ij

UC UCUC UC

C U

U U

C U

C C U d dV V

s

s

C

2 1

0 ( )

,

Local stress-strain field

= pq

ij p q ijvs s x x

,

0

,

Homogenised stress-strain field

( )

ijkl k lj

i i

ij ijkl k l

C u f

u v

C u

s

u x x x

x

x x

FE

FE


45

89

Example: Finite element model of 3D woven composite

Mesh in the yarns

Full mesh

Clearance between yarns 0.005 mm

Resin layer on the surface 0.005 mm

VF 43.7% (WiseTex: 48.9%)

Total elements 20768

Penetrating nodes corrected 3000

Max aspect ratio 469

Max aspect ratio in yarns 60

WiseTex

MeshTex

Correct representation of measurable

parameters:

• areal density

• thickness

• overall fibre volume fraction

• ends/picks count

• yarn dimensions

Simplifications:

• elliptical shape of yarn cross-sections

• constant dimensions of Z-yarns

• VF inside yarns up to 90% (Z-yarns)


Strains on the surface of the composite


46

Stress-strain diagram

0

50

100

150

200

250

300

350

400

450

500

0 0.5 1 1.5 2 2.5 3

eps, %

sig

, M

Pa

exp

elastic solution


92

Damage model – 1

Damage initiation: Hoffmann

2

9

2

8

2

7654

23

22

21 )()()(

LTZLTZZTL

TLLZZT

CCCCCC

CCCF

sss

ssssss

2

9

2

8

2

7

654

3

2

1

1,

1,

1

11,

11,

11

111

2

1

111

2

1

111

2

1

sLT

sZL

sTZ

cZ

tZ

cT

tT

cL

tL

cZ

tZ

cT

tT

cL

tL

cT

tT

cL

tL

cZ

tZ

cL

tL

cZ

tZ

cT

tT

FC

FC

FC

FFC

FFC

FFC

FFFFFFC

FFFFFFC

FFFFFFC

Definition of the damage mode

L T

Z


47

93

Damage model – 2


94

Tensile diagrams, 3D composite

• correct modelling of degradation

of stiffness

• reasonable evaluation of damage

initiation threshold

• qualitative representation of

intensity of damage S.V. Lomov - Textile Preforms for Composites - 5. Modelling 94

48

95

Progressive damage, 3D composite


References

1. Bedogni, E., D.S. Ivanov, S.V. Lomov, A. Pirondi, M. Vettori, and I. Verpoest, Creating finite element model of 3D woven fabrics and composites:

semi-authomated solution of interpenetration problem, in 15th European Conference on Composite Materials (ECCM-15). 2012: Venice. p.

electronic edition, s.p.

2. Lamers, E.A.D., S. Wijskamp, and R. Akkerman, Modelling shape distortions in composite products, in Proceedings ESAFORM-2004. 2004:

Trondheim. p. 365-368.

3. http://www.optitex.com/

4. Sozer, E.M., S. Bickerton, and S.G. Advani, On-line strategic control of liquid composite mould filling process. Composites Part A: Applied Science

and Manufacturing, 2000. 31(12): p. 1383-1394.

5. http://www.esi-group.com/

6. Duhovic, M., P. Mitschang, and D. Bhattacharyya, Modelling approach for the prediction of stitch influence during woven fabric draping.

Composites Part A, 2011. 42: p. 968–978.

96 S.V. Lomov - Textile Preforms for Composites - 5. Modelling

http://www.optitex.com/

http://www.esi-group.com/



Documents

Textile Preforms for Composites - KU Leuven · 2014-12-20 · Yarn properties Ends/picks count Weave coding Yarn shapes Full description of the geometry Input Distance between the