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Advanced Composite Simulation
September 25th 2014, Montréal
Benoît Magneville – [email protected] LMS Engineering
Project Manager, Composite Expert
2014-09-25
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Advanced Composite Simulation
Engineering challenges
OPTIMIZATION to minimize weight
Manufacturing Many potential DAMAGE
mechanisms
Temperature affects behavior
Manage acoustic performance with reduced weight
Unknown vibrational behavior
Stiffness reduction
and failure due to
FATIGUE
Resistance to Lightning (in development)
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Advanced Composite Simulation
LMS Engineering, composite development partner
2014-09-25
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Agenda
• Application of material identification methodology for advanced
damage analysis of Composites
• Composites structure optimization under Sizing and Design
constraints
• Fatigue of Continuous Fiber Composites for Variable amplitude loads:
a new methodology
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Which composites are considered here?
• Load carrying structural parts
Continuous fibers,
structured laminated
composite
Unidirectional ply
(UD)
Multi-axial plies NCF
(Non Crimp Fabric)
Woven fabric
• High performance structured composites (low weight, high stiffness and
strength)
Aerospace application Automotive application
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Application of material identification
methodology for advanced damage
analysis of Composites
Benoît Magneville – [email protected]
2014-09-25
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Damage in Composites:
LMS Samtech solutions based on Continuum
Damage Mechanics (CDM)
Intra-laminar failure Inter-laminar failure
• Damage evolution law by Ladeveze and Allix • Damage modeling of the elementary ply for laminated composites, Composites Science and Technology 43, 1992
Non-local
Model with
coupling
Native damage
models in LMS
Samcef
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Damage in Composites:
LMS Samtech solutions based on Continuum
Damage Mechanics (CDM)
• The approach is based on the Continuum Damage Mechanics
• Intra-laminar failure of the unidirectional plies
ALONG THE FIBERS IN THE MATRIX
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• Inter-laminar failure: Delamination
Damage in Composites:
LMS Samtech solutions based on Continuum
Damage Mechanics (CDM)
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Damage in Composites:
LMS Samtech solutions based on Continuum
Damage Mechanics (CDM)
Availability at all stages of end-to-end testing process
• From composite materials identification at coupon level
• To composite structures sizing at components & full scale level
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Damage material properties identification with
coupon analyses
Challenges:
Identify the non linear material properties at the coupon level
Have accurate material models for the progressive damage
modeling, easy to use
Solution:
Native damage models for inter and intra-laminar failures
(Cachan models)
LMS Engineering knowledge for parameter identification
Transfer of technology
Benefits:
Virtual material testing, with the non-linearities
Determine allowables in a damage tolerant approach
Input for detailed sizing
02322
223
01312
213
01212
212
332202
023
331101
013
221101
012
0322
233
03
233
02
222
0222
222
0111
211
)1(2)1(2)1(2
)1(222)1(2)1(2
GdGdGd
EEE
EdEEEdEded
Coupon level
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Damage material properties identification with
coupon analyses
• Tests needed
• Number of tests
• Associated standards
• Test output requested
• Parameter identification procedure: a comprehensive test protocol exists
• Technology-transfer projects are proposed for parameters identification
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Challenges • Weight saving requirements instigate adoption of light weight laminated
composite materials in body design
• Use of new materials necessitates the development of new design
performance evaluation methodology
• The reliability & strength behaviour of composites under complex loading is
non-linear
• Need for development of predictive models and related material
characterization procedures for progressive damage analysis and body
performance evaluation
Solution • LMS Samcef Mecano non-linear finite element solver
• LMS Engineering Services for composite damage model identification
Results • Sophisticated material models comprehensively implemented for:
• Progressive ply damage (strength, non-linearities, plasticity, coupling
effects in the matrix)
• Delamination (possibly coupled to damage in the plies)
• Development of the parameter identification procedure, based on a limited
amount of physical tests on coupons
• Predictive damage models at the coupon level and at composite subsystem
design concept level
Honda R&D Co., Ltd.
Innovative Methodology for Progressive Damage
Analysis in Composite Design
Composite Delamination
Progressive ply damage
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Exploitation of the methodology
• Validation of damage models at coupon level Starting from identified material parameters, the damage model is used to predict
the mechanical behavior at the coupon level for evaluation of the behaviour for
other stacking sequences and hence replacing physical tests.
• Application of damage models for predictive
delamination behavior at component level The damage models are supporting the prediction of the progressive damage
and delamination inside the plies and at their interface at component level
Honda R&D Co., Ltd.
Innovative Methodology for Progressive Damage
Analysis in Composite Design
Progressive ply damage
Progressive delamination
Source : “Strength Calculation of Composite Material considering multiple progress of failure by
Ladaveze model”, Y.Urushiyama, T. Naito, JSAE Spring Conference, 2014 52 05
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• Application of damage tolerant approach for composite design • Barely visible impact damage
• Damage induced by a low energy impact
• Delamination appears at the interfaces between the plies
• Agreement between simulation and C-scan test results
Honda R&D Co., Ltd.
Innovative Methodology for Progressive Damage
Analysis in Composite Design
The stains represent the level of delamination
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LATECOERE
Delamination of a pre-cracked stiffener
Existing crack
Existing cracks Cap (4 plies)
[45/90/0/-45]
Skin (9 plies)
[0/90/45/0/-45/90/0/45/-45]
Imposed displacement
Flange- left part (4 plies)
[-45/90/0/45]
Clamp
Challenges:
Investigate the damage propagation at the interfaces of
plies in a composite structure
Multi-delaminated composite material
Many contact conditions between initial defects
Fast solution procedure
Solution:
LMS Samcef with a specific approach for modeling
delamination
LMS Samcef solution with efficient solvers
Benefits:
Better knowledge of the composite structure, with a
damage tolerant approach
Decrease the safety margins for the composite design
Component level
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DAHER
Test Prediction on stiffened panel
Challenge:
• Evaluate the quality of the test facilities
Solutions:
• LMS Samcef Field for the pre/ post processing
• LMS Samcef non linear solver
• Interlaminar + Intralaminar damage
Benefits:
• Very accurate results
• New design for the test facilities
proposed
Component level
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Benefits:
Better knowledge of the non linear structural behavior
Virtual prototype of stiffened panels
Test
Simulation
Challenges:
Non linear analysis of thin-walled damaged stiffened
composite panels: buckling, post-buckling and collapse
Accurate results and fast solution procedure
Solution:
SAMCEF non linear solver
Use of advance progressive damage laws at the detailed
sizing level
DLR
Composite panel with de-bonding stringer
Sub-system level
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AIRBUS GROUP INNOVATIONS
AIRBUS HELICOPTERS
Damage analysis on composite Helicopter Blade
Challenges:
Investigate the composite damage in a pre-cracked helicopter
blade.
Check the simulation capabilities to predict the damage evolution
Solution:
SAMCEF modeling tools and non linear solver
Use of advance progressive damage laws at the detailed sizing
level
Damage mesomodel
Elastic behaviour
Benefits:
Prediction of final load and prediction of the damage evolution
was performed with success
Better knowledge of the non linear structural behavior
DIC results
Sub-system level
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CEA
Engineering Service: Burst Test Simulations Using
Advanced composite modeling
Challenges:
• Hydrogen storage is a key issue for the high
scale deployment of fuel cell applications
• Necessary to reach a significant cost
reduction of these storage systems
• Optimization of the composite structure can be
reached thanks to numerical simulation
Solution:
• Parametric Finite Element model
• Use of complex damage modeling for burst
mode type identification
• Use LMS Samcef Mecano solver
Benefit :
• Good correlations with reference tests
• Optimization results – Mass decreased by >30%
• Development of adapted method and tools
Sub-system level
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Composites structure optimization under
Sizing and Design constraints
Benoît Magneville – [email protected]
2014-09-25
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Optimization
Brief overview of LMS Samtech Samcef capabilities
Optimization with
geometric non linearites
(buckling, post-buckling,
collapse)
Local optimization
Optimization wrt ply
thickness & fibers
orientation
Local optimization
Stacking Sequence
Optimization (design
rules + inter-regional ply
continuity)
Local/global optimization
Very Large scale
optimization problems
Global Optimization
• Local optimization (thickness, fiber orientation)
• Stacking sequence optimization with manufacturing constraint
• Vary large scale optimization (preliminary design of full structures)
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Optimization methods
• Genetic Algorithms
• Response Surface Methods • based on an imported data base
• based on a DOE created with our tool (Taguchi tables, D-optimal, …)
• Surrogate Based Optimization • based on a response surface with NN
• based on GA
• enriched data base at each iteration
• Specific integer programming
• For stacking sequence optimization of composite structures
• Gradient based methods
• MP: SQP, Multiplier, CG
• SCP: Conlin, MMA, GCM, …LARGE SCALE OPTIMIZATON
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AIRBUS
Geometric NL behavior of stiffened panels, up to final
collapse
d
Buckling Post-buckling Collapse
Collapse
Unstable path
Decrease the weight and
put those points to
prescribed values
Stiffened composite panels
Thin walled structures
= load factor
d = transverse displacement
Buckling
0 jj ΦSK
Linear analysis
Post-buckling
0)()(),( int qFFqF ext
Non linear analysis
d
• 1st step: Local optimization
• Minimize the weight while keeping buckling and collapse load above
prescribed values
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AIRBUS
Geometric NL behavior of stiffened panels, up to final
collapse
Panel: 3 d.v. t0°, t90°, t45°
Hat: 3 d.v. t0°, t90°, t45°
Total: 36 d.v.
? 0°
? 90°
? 45° ? -45°
? 0°
? 90°
? 45°
? -45°
• 1st step: Local optimization
• Preliminary study: Total thickness of each UD orientation is a continuous variable
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AIRBUS
Geometric NL behavior of stiffened panels, up to final
collapse
• Initial Assumption: Buckling optimization: Linear stability analysis in the optimization loop
0
0.5
1
1.5
2
2.5
3
0 2 4 6 8 10 12 14
Iterations
Desig
n functions
1
Relative weight
Weight min
1boundRFbuckling
Weight = 1.
1 = 2.7
Weight = 0.69
1 = 1.2
collapse = 1.05 < 1.2
Non linear analysis
must be included into
the optimization loop
collapse
Non conservative solution !
Due to geometric non-linearities
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AIRBUS
Geometric NL behavior of stiffened panels, up to final
collapse
Weight min
1boundRFbuckling
2boundRFcollapse
0
0.5
1
1.5
2
2.5
3
0 2 4 6 8 10
Iterations
Desig
n functions
1
collapse
Relative weight 0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 10 20 30
Transversal displacement (mm)
Lo
ad
fa
cto
r
Weight = 0.61
1 = 0.8
collapse = 1.2
0
0.5
1
1.5
2
2.5
0 10 20 30 40
Transversal displacement (mm)
Lo
ad
fa
cto
r
Weight = 1.
collapse = 2.1
1 = 2.7
We can tune the shape of the
load-displacement curve
• Correct Assumption: Buckling, post-buckling and collapse optimization (NL analyses)
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AIRBUS
Geometric NL behavior of stiffened panels, up to final
collapse
Weight = 1.
collapse = 2.1
1 = 2.7
Bad thicknesses and
fibers proportions
Global buckling mode
Initial design
Heavy structure
Weight = 0.61
1 = 0.8
collapse = 1.2
Good thicknesses and
fibers proportions
Local buckling modes,
before the collapse
Optimal design
Safer and lighter
structure
• 1st step: Local optimization: Conclusion
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Local-global optimization
Stacking sequence optimization over a structure
• 2nd step: Local/Global optimization (Stacking sequences optimization)
In each zone, optimal stacking sequence
(plies at 0°, 90°, 45°, -45°)
Design rules
Across the zones, manufacturing constraint (ply continuity)
OK
KO
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Local-global optimization
Stacking sequence optimization over a structure
Backtracking algorithm optimal stacking sequence table generator
Data from step 1 Nb of plies Number of plies
For a given number of
plies, optimal stacking
sequence
Ply drops between the
zones: ply continuity
OK
KO
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Local-global optimization
Stacking sequence optimization over a structure
Local and Local-Global optimization Conclusion
0°
90°
45° -45°
0°
90°
45°
-45°
Step 1: optimization of ply
thickness for 0, 90, 45 and -45
Step 2: backtracking (plies shuffling)
Min weight
Stability constranits
Possibly with NL
analysis
- Design rules OK
- Manufacturing constraint OK
- Buckling / Collapse OK
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Wings
1000 DV’s
250000 Constraints
Central Wing Box
250 DV’s
160000 Constraints
Vertical Tail Plane
100 DV’s
100000 Constraints
Horizontal Tail Plane
100 DV’s
100000 Constraints
Optimal preliminary sizing of the A350
Large-scale optimization
Centre Wing
Box
Horizontal Tail
Planes
Vertical Tail
Plane
Outer Wing
Box
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Optimal preliminary sizing of the A350
Large-scale optimization
• Panel design variables
Design Variables:
t – Skin Thickness
p0 – Percentage 0-degree
p90 – Percentage 90-degree
Design Variables:
ba - Stringer foot width
h - Stringer height
ta – Stringer angle thickness
tb – Stringer core thickness
• Stiffener design variables
NXYg
NXYd
NXd
NYd
NXg
NYg
PX
• Super-stringers
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Optimal preliminary sizing of the A350
Large-scale optimization
• Sizing criteria taken into account in the optimization
• Mass
• Buckling
• Damage tolerance
• Reparability
• Design rules
• Micro-strains
• …
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Fatigue of Composites for Variable
amplitude loads: a new methodology
Benoît Magneville – [email protected]
2014-09-25
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Fatigue of continuous fiber composites
Advantage and challenge
• Composites typically show good fatigue
behavior (many load cycles till failure)
• But: Fatigue onset is very early
Macroscopic stiffness change
• Therefore: Designing for fatigue vs. no
damage means:
• Benefit from good fatigue behavior
• Extra weight reduction
Unidirection
al ply
Multi-axial
plies NCF Woven
fabric
Light weight advantage
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Fatigue of continuous fiber composites
Progressive Stiffness Degradation Modeling
Typical stiffness degradation curve
3 phases
Continuum Damage Mechanics framework
with damage growth rate equation dD/dN
𝜕𝑑𝐼
𝜕𝑁= 𝑐1 ∙ Σ𝐼 ∙ 𝑒
−𝑐2𝑑𝐼
Σ𝐼 + 𝑐3 ∙ 𝑑𝐼 ∙ Σ𝐼2 1 + 𝑒 𝑐5 Σ𝐼−𝑐4
(W.V.Paepegem, 2001)
• Intra-laminar failure for the UD (same approach as Cachan static damage model)
e
E0
E0(1-d)
0
2322
2
23
0
1312
2
13
0
1212
2
12
33220
2
0
2333110
1
0
1322110
1
0
12
0
322
2
33
0
3
2
33
0
2
2
22
0
222
2
22
0
111
2
11
)1(2)1(2)1(2
)1(222)1(2)1(2
GdGdGd
EEE
EdEEEdEded
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Fatigue of continuous fiber composites
Constant amplitude loading (Past experience)
Work with an university partner, expert in fatigue of composites:
Ghent University (Belgium) – Prof. Wim Van Paepegem
1. Static cycle
2. Fatigue law ...
N
d
3. Increase of the damage variable (Dd), for the
Gauss point on all elements
4. Determine DN (= NJUMP « global »)
5. Update the damage level Ddi (loop on the elements)
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Fatigue of continuous fiber composites
Variable amplitude loading
Improved Cycle Jump algorithm
• Tests and calculation on ply level
• Possible lay-up optimization
• No new tests for variable amplitude
• Stiffness degradation and stress redistribution
Proven hysteresis operator approach
• Only efficient approach to cover continuous loss
in stiffness and fatigue resistance
Allows simulation of full structures Brokate, M; Dressler, K; Krejci, P: Rainflow counting and energy
dissipation in elastoplasticity, Eur. J. Mech. A/Solids 15, . 705-737,
1996
Nagode, M., Hack, M. & Fajida, M. “High cycle thermo-mechanical
fatigue: Damage operator approach”, Fatigue Fract Engng Mater
Struct 32(6), 505-514, Wiley & Son, 2009
Nagode, M., Hack, M. & Fajida, M., “Low cycle thermo-mechanical
fatigue: Damage operator approach”, Fatigue Fract Engng Mater
Struct 33(3), 149-160, Wiley & Son, 2010
Nagode, M. & Hack, M.: “The damage operator approach, creep
fatigue and visco-plastic modeling in thermo-mechanical fatigue”,
SAE International Journal of Materials & Manufacturing, 4(1), 632-
637. doi:10.4271/2011-01-0485, 2011.
Van Paepegem, W ; Degrieck, J; “Fatigue Degradation modelling
of plain woven glass/epoxy composites”, Composites: Part A
32:1433-1441, 2001
Van Paepegem, W.; “Development and finite element
implementation of a damage model for fatigue of fiber reinforced
polymers” Ph. D. thesis, Department of Material Science and
Engineering, Ghent university, 2002.
Xu, J., Lomov, S.V., Verpoest, I. Daggumati, I., Paepegem, W.
Van and Degrieck. J., “Meso-scale modeling of static and fatigue
damage in woven composite materials with finite element method.”
presented in 17th International Conference on Composite Materials
(ICCM-17). 2009. Edinburgh: IOM Communications Ltd.
Xu, J; “Meso Finite Element Fatigue Modelling of Textile
Composites” Ph. D. thesis, Dept MTM, Katholieke Universiteit
Leuven, Belgium, 2011
2014-09-25
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Fatigue of continuous fiber composites
Conclusion
Fatigue behaviour of Metals
& Composites
Exploit full advantage of
the gradual stiffness
degradation characteristics
of composite in design
Include dynamic loading in the
design process
Complex cyclic loading
scenarios
FE Composite
Modelling
Technology for
composite durability
evaluation based on
progressive stiffness
degradation model
Fiber orientation & Ply
stacking
Efficiency Accuracy
Fatigue material
properties at ply level
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Fatigue of continuous fiber composites
Conclusion
Engagement model
• Engineering Services & Transfer of Technology
Test set up
Material
Characterization
FE Composite
Modelling
Assistance for test design and set-up
• Workshops
• Tests specifications
• Characterize Material
• Tools based on standard software
• Lead through process
• User defined damage models
Material characterization
Fatigue calculation
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Thank you
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20XX-XX-XX Page 42 Siemens PLM Software
Benoît Magneville – [email protected]
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