Global-local analysis of composite structures using the ...GL/MUL2_GL_Sept19-1.pdfGlobal-local...
Transcript of Global-local analysis of composite structures using the ...GL/MUL2_GL_Sept19-1.pdfGlobal-local...
Global-local analysis of composite
structures using the MUL2@GL tool
Erasmo Carrera, Alberto G. de Miguel, Matteo Filippi, Ibrahim Kaleel, Alfonso
Pagani, Marco Petrolo & Enrico Zappino
Turin (Italy), September 27, 2019
Politecnico di Torino
1
Mul2 Research Group - DIMEAS
Mul2 Group www.mul2.polito.com
MUL2 research group @ PoliTO
2
Aeroelasticity
Composites
Computational Mechanics
In NUMBERs:• 6 Academic Staff• 4 Post-Doc• 6 PhD Students• Many visiting…
PROJECTs:H2020, FP7, ESA, INDUSTRIAL PROJECTs, CLEAN-SKY
Bio-Mechanics
PARTNERs:EMBRAER, PURDUE, ENSAM, CALTECH, NASA…
Rotor Dynamics
Failure
MultifieldFinite
Elements
Mul2 Group www.mul2.polito.com
The challenge of composite simulation
3
Macro Structur
e
Structuralcomponent
Lamina
& Layer
Matrix & Fibre
Macro-scale101 m
Macro-scale100 m
Meso-scale10-2 m
Micro-scale10-6 m
Classical FEM Models
Matrix\Fiber FailureCrack propagation
Micro-bucklingEtc
Delamination/ debond
Failure Indexes• Max Stresses\Strains• Tsai-Wo, Tsai-Hill• …Delamination Analysis• Cohesive elements• …
Refined 3D modelsCrack propagation…
PeridynamicsHomogenizationFailure Indexes• Puck • Hashin• LaRC03• LaRC04• LaRC05
Free-edge effects
Structuralresponse
Interlaminar stresses
Mul2 Group www.mul2.polito.com
Available models for composite analysis
4
• Appropriate models for composite laminates are:
- beam/plate/shell models based on higher-order
kinematics;
- layer-wise approximations;
- zig-zag models;
- mixed formulations (e.g., RMVT);
- all are particular cases of CUF.
• By using commercial tools (i.e., Nastran, ABQ, etc.), users
shall employ 3D brick elements (4/5 per layer).
• This is still possible for small parts (coupon size), but
unfeasible for full-scale real life structures.
• As a consequence, in the industrial practice we use simplified
laminated plate models, “magic” failure indexes, and
invariants, which seriously alter the safety margins and shrink
the design space!
Allix, O. “Virtual delamination testing through non-linear multi-
scale computational methods: some recent progress”, Computers,
Materials and Continua 2013
Mul2 Group www.mul2.polito.com
Scope
5
• What if we have the capability to integrate advanced modelling techniques for the accurate analysis of composites
into current analysis/design tools and without changing the formalism of already available FEM models?
• What if we have the capability to cheaply (online) measure and assess stress/strain distributions and 3D failure
indexes (LaRC, 3D Hashin, etc.) in individual critical components or zones of our FEM model?
• We can then move towards disrupting our current approaches, e.g.:
- Design/optimize the structure taking into account the real stress states and margins.
- Reveal unfeasible design solutions already in the preliminary phase and save time for the subsequent detail
analysis process.
Mul2 Group www.mul2.polito.com
Theory: global-local method
6
C. Collier et al. “An approach to preliminary design and
analysis”, In 48th AIAA/ASME/ASCE/AHS/ASC Structures,
Structural Dynamics, and Materials Conference, 2007
• One-way coupling: displacements & rotations from global FEM model to
local model
• The critical elements are chosen as local models
Our method:
a a
c ca
m ma ic g a i
ig i i ca m
i ac m
Mul2 Group www.mul2.polito.com
Why?
7
E11 = 40 GPa, E22 = E33 = 4.0 GPa, ν12 = ν13 = ν23 = 0.25, G12 = G13 = G23 = 1.0 GPa
Ply properties:
Geometry:
L = 2 m, b = 0.1 m, t = 3 mm
1
[0 45 −45 90 45 −45 ]
LW model
ESL model
Up to 30%
error
Mul2 Group www.mul2.polito.com
Why?
8
E11 = 40 GPa, E22 = E33 = 4.0 GPa, ν12 = ν13 = ν23 = 0.25, G12 = G13 = G23 = 1.0 GPa
Ply properties:
Geometry:
L = 2 m, b = 0.1 m, t = 3 mm
1
[0 45 −45 90 45 −45 ]
LW model
ESL model
Up to 30%
error
LaRC5 Matrix Failure:
Mul2 Group www.mul2.polito.com
9
MUL2@GL tool
Mul2 Group www.mul2.polito.com
MUL2@GL tool
10
Standalone package ‘MUL2@Global- ca ’
Mul2 Group www.mul2.polito.com
MUL2@GL tool
11
Standalone package ‘MUL2@Global- ca ’
Installation in FEM softwares
• : C ‘ ba - ca ’ into ‘a i’
• Abaqus: C ‘ ba - ca ’ into ‘abaqus_plugins’
Inputs
Nastran
- Input file (bdf)
- Ouput file (op2)
- Material allowables
Abaqus
- Output file (odb)
- Material allowables
Outputs
3D strains, 3D stresses and failure indexes
- Coordinate systems: local, global and lamina
- Stress failure index: Hoffman, Hashin 3D, LaRC5
- Instantaneous visualization
- Stored data files: csv, dat and post in Femap &
Abaqus
Mul2 Group www.mul2.polito.com
12
Aeronautic showcase
• Material: similar to IM7
• Lay-up: min 28 layers, max 62 layers
FEMAP model Deformed
Mul2 Group www.mul2.polito.com
13
Aeronautic showcasePly Thickness Angle
1 0.183 45
2 0.183 -45
3 0.183 0
4 0.183 45
5 0.183 0
6 0.183 90
7 0.183 0
8 0.183 45
9 0.183 45
10 0.183 0
11 0.183 0
12 0.183 45
13 0.183 0
14 0.183 -45
15 0.183 45
16 0.183 0
17 0.183 0
18 0.183 0
19 0.183 90
20 0.183 90
21 0.183 -45
22 0.183 -45
23 0.183 0
24 0.183 -45
25 0.183 0
26 0.183 -45
27 0.183 0
28 0.183 0
29 0.183 0
30 0.183 90
31 0.183 0
32 0.183 0
33 0.183 90
34 0.183 0
35 0.183 0
36 0.183 0
37 0.183 -45
38 0.183 0
39 0.183 -45
40 0.183 0
41 0.183 -45
42 0.183 -45
43 0.183 90
44 0.183 90
45 0.183 0
46 0.183 0
47 0.183 0
48 0.183 45
49 0.183 -45
50 0.183 0
51 0.183 45
52 0.183 0
53 0.183 0
54 0.183 45
55 0.183 45
56 0.183 0
57 0.183 90
58 0.183 0
59 0.183 45
60 0.183 0
61 0.183 -45
62 0.183 45
3D stress solutionsLocal element
Mul2 Group www.mul2.polito.com
Tutorial example
Sym
Sym
Fixed
Rigid conn
Force
Reinforced composite panel
• Material: IM7/8552, ht=0.2 mm
• Lay-up: [0/90/45/-45/02]S
Mul2 Group www.mul2.polito.com
Tutorial example
Reinforced composite panel
• Material: IM7/8552, ht=0.2 mm
• Lay-up: [0/90/45/-45/02]S
Mul2 Group www.mul2.polito.com
Tutorial example
Reinforced composite panel
• Material: IM7/8552, ht=0.2 mm
• Lay-up: [0/90/45/-45/02]S
Max Hoffman FI = 0.2739
Mul2 Group www.mul2.polito.com
Tutorial example
Running MUL2@GL as a standalone
Selection of input model
Selection of Nastran results
Destination folder for stored outputs
Input critical elements for local analysis
Choice of failure criteria
Input material strengths
Direct comparison with Nastran shell
results
Mul2 Group www.mul2.polito.com
Tutorial example
Outputs
Mul2 Group www.mul2.polito.com
Tutorial example
Outputs
Mul2 Group www.mul2.polito.com
Tutorial example
Outputs
• Comma-separated values (csv) for Excel
• Data table (dat)
• Folder with postprocessing files for FEMAP
Mul2 Group www.mul2.polito.com
Documentation
21
Publications Detailed tutorial
Mul2 Group www.mul2.polito.com
MUL2@GL available soon …
22
Mul2 Group www.mul2.polito.com
Free-edge analysis
23
Free-edge concentrations
C MITTELSTEDT AND W BECKER. “’Interlaminar Stress
Concentrations in Layered Structures: Part I – A Selective
Literature Survey on the Free-Edge Effect since 1967”, Journal
of COMPOSITE MATERIALS, Vol. 38, No. 12/2004
Extension
09
0
900
Bending
09
0
900
Mul2 assessment
Mul2 Group www.mul2.polito.com
Free-edge analysis
24
Tensile test – composite coupon
Mul2 Group www.mul2.polito.com
Free-edge analysis
25
Selection of a local element in the free edge of the coupon
Activation of free-
edge analysis
Mul2 Group www.mul2.polito.com
Free-edge analysis
26
Definition of the free-edge side of the selected local element thourgh the node ids
Mul2 Group www.mul2.polito.com
Free-edge analysis
27
Visualization of the free-edge strains and stresses
• All the outputs are also saved in dat and csv format
Mul2 Group www.mul2.polito.com
Free-edge analysis
28
Comparison with literature semi-analytical solutions
T LORRIOT, G MARION, R HARRY, H WARGNIER. “Onset
of free-edge delamination in composite laminates under tensile
loading”, Composites Part B: Engineering, Vol. 34, No. 5, 2003
Ref:
Thank you for the attention
29