Workshop II MicMac Jan12

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COMPOSITES DESIGN WORKSHOP II

MIC-MAC TOOL

Pranav Dhoj Shah, PhD

SESSION D: JANUARY 12, 2010

TOPICS

MIC-MAC/PD AND PDFLEX

Simultaneous vs. Progressive degradation scheme

Failure Envelopes

Effect of degradation factor Em*

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SIMULTANEOUS VS PROGRESSIVE DEGRADATION

On onset of First Ply Failure, all plies are degraded at

once (simultaneous degradation)

On onset of First Ply Failure, only the failed ply is

degraded and analysis is run again.

This loop is repeated until all

plies fail.

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MICMAC/PD

Ply and laminate data

Applied load

Vectors to plot the failure envelope

Launch failure envelope plot

Plot stress, strain curves

Stress and strain and strength ratio.

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MICMAC/PD

Ply and laminate data

Stress-strain calculated by Mic-Mac-PD

Failure envelope plot

Data populated by Mic-Mac-PD for failure envelope plot

Stress-Strain curve for the applied load

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MICMAC/PD

Scale mismatchResize the graph to make the green line in 45o

slope.Now scaled.

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PROGRESSIVE DAMAGE

EXAMPLE: PLOTTING STRESS-STRAIN CURVES

- Application: Mic-Mac/ PD

- Material: Im6/epoxy [Eng]

- Laminate: [±45/0]s

- Applied in-plane load: {N} = {1, 0, 0} ksi-in

- Plot stress-strain curve

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PROGRESSIVE DAMAGE

EXERCISE: PLOTTING STRESS-STRAIN CURVES

- Application: Mic-Mac/ PD

- Material: T300/N5208 [Eng]

- Laminate: [±45/0]s

- Applied in-plane load: {N} = {1, 0, 0} ksi-in

- Plot stress-strain curve

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SIMULTANEOUS VS PROGRESSIVE DEGRADATION

STUDY CASE

Material: Im6/epoxy [SI]Laminate: [0/90/45/-45]sLoad : {1,0,0} MN/m

COMPARE USING:Mic-Mac/Inplane (Simultaneous degradation)Mic-Mac/PD (Progressive degradation)

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SIMULTANEOUS VS PROGRESSIVE DEGRADATION

0

200

400

600

800

1000

1200

1400

0 10 20 30

sig

ma-1

(M

Pa o

r ksi)

epsilon-1 (E-3)

stress strain curve

0

200

400

600

800

1000

1200

1400

0 10 20 30

sig

ma-1

(M

Pa o

r ksi)

epsilon-1 (E-3)

stress strain curve

Mic-Mac/ Inplane

Simultaneous degradation

Mic-Mac/ Inplane

Simultaneous degradation

[90] 385 MPa

[0] 1168 MPa [0] 1168 MPa

[90] 385 MPa

[±45]

[90]

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SIMULTANEOUS VS PROGRESSIVE DEGRADATION

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SIMULTANEOUS VS PROGRESSIVE DEGRADATION

For laminates under homogeneous stress state, simultaneous degradation is a viable shortcut

method to estimate the strength.

For laminates under non-homogeneous stress state, e.g., for notched specimen, specimen with

constrained boundary conditions, etc., simultaneous degradation may not be accurate.

Refer to Section 9.6 for further information.

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FAILURE ENVELOPES USING MIC-MAC/PD

EXAMPLE:

Plot a failure envelope in terms of sigma1-sigma2 for

Material: Im6/epoxy [SI]

Laminate: QI [0/90/+-45]s

1

2

3

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FAILURE ENVELOPES USING MIC-MAC/PD

s1

s2

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FAILURE ENVELOPES USING MIC-MAC/PD

EXERCISE:

Plot a failure envelope in terms of sigma1-sigma2 for

Material: Im6/epoxy [SI]

Laminate: QI [0/+-60]s

1

2

3

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FAILURE ENVELOPES USING MIC-MAC/PD

EXAMPLE: HYBRID LAMINATES:

Failure envelope in terms of sigma1-sigma2 for

Material: E-Glass/epoxy and Im6/epoxy [Eng]

Laminates: [90(E-glass)/0(Im6)] and [0(E-glass)/0(Im6)]

Strength-wise, is it beneficial to place CFRP and GFRP fibers parallel to each other?

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FAILURE ENVELOPES USING MIC-MAC/PD

Having equal ply angles (CFRP and GFRP) nothing is gained and may have two losers.

-100

-80

-60

-40

-20

0

20

40

60

80

100

-300 -200 -100 0 100 200 300 400

s igm a-2 (Mpa,ks i)s igm a-2 (Mpa,ks i)

-100

-80

-60

-40

-20

0

20

40

60

80

100

-300 -200 -100 0 100 200 300 400

s igm a-2 (Mpa,ks i)s igm a-2 (Mpa,ks i)

[0(E-glass)/0(Im6)]

[90(E-glass)/0(Im6)]

s2

s2

s1

s2

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-2500

-2000

-1500

-1000

-500

0

500

1000

-2500 -2000 -1500 -1000 -500 0 500 1000

ULT (Em*=0.15)

ULT (Em*=0.01)

ULT (Em*=0.5)

EFFECT OF DEGRADATION FACTOR Em* on R/LPF

Material: T300/N5208 [SI]

Laminate: QI (p/4)

Degradation factors Em*=0.5, 0.15, 0.01

s2

s1

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MIC-MAC/PD FLEX

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LAMINATE DEFINITION:

Also applicable to hybrid laminates

For top laminate:

First row is for the outermost ply

For bottom laminate:

First row is for the outermost ply

For Sandwich core (cell D24):

PDFLEX is only applicable for core thickness≠ 0.

In-plane load {N} and bending loads {M}

Vector points for failure envelope plots.

Sandwich core (z=half thickness)

Symmetric face

Symmetric face

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EXAMPLE

Material: T300/N5208 [SI]

Laminate: [(+45/0)s/c]s c: core thickness (half of total core thickness) = 0.1m

Bending loads: {M} = {1,0,0}

Find the sequence of ply failure.

MIC-MAC/PD FLEX

HOMEWORK 4.1

Plot failure envelope in terms of sigma1-sigma2 for

Material: Im6/epoxy [SI]

Laminate: QI [0/90/+-45]s

Copy and paste the failure envelope to a new Excel sheet.

Now plot similar failure envelope for :

[0/60/-60]s

Compare the two failure envelopes.

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