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TOPICS
MIC-MAC/PD AND PDFLEX
Simultaneous vs. Progressive degradation scheme
Failure Envelopes
Effect of degradation factor Em*
2
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.
3
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.
4
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
5
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
7
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
8
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)
9
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]
10
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.
12
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
13
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
15
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?
16
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
17
-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
18
MIC-MAC/PD FLEX
19
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
20
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