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Datum: 25 – 26. Juni 2018Ort: 15. Deutsches LS-Dyna Forum, Bamberg, 2018
Infiltration Simulation and Virtual Permeability Determination for the Digital Prototype
Digitaler Prototyp
DigitPro - J. Dittmann, P. Middendorf
Institute of Aircraft Design
PERMEABILITY PREDICTION
J. Dittmann, P. Böhler, D. Michaelis, M. Vinot, C. Liebold, F. Fritz, H. Finckh, P. Middendorf. „DigitPro – Digital Prototype Build-up Using the Example of a Braided Structure.” IMTC, 2015
11DigitPro - J. Dittmann, P. Middendorf
� How to predict permeability values of near-net-shape
parts with varying fibre orientations ?
IFB
IFB
BEFORE DIGITPRO
J. Dittmann, P. Böhler, D. Michaelis, M. Vinot, C. Liebold, F. Fritz, H. Finckh, P. Middendorf. „DigitPro – Digital Prototype Build-up Using the Example of a Braided Structure.” IMTC, 2015
22DigitPro - J. Dittmann, P. Middendorf
Classical way of permeability determination.
Flow front development after 28,3 s; 43,3 s und 63,3 s
Data / alternative Facts:
• Infiltration pressure: 2 bar• FVC: 52 %• 4 layer triaxial braid: Toho Tenax 12K (589 g/m2;
0/±45)• Fluid: Glycerol 85 %• Aluminum bottom mould• PMMA top mould + Steel stiffeners
Radial in-plane permeability determination
Experimental permeability determination
IFB IFB
IFB
BEFORE DIGITPRO
J. Dittmann, P. Böhler, D. Michaelis, M. Vinot, C. Liebold, F. Fritz, H. Finckh, P. Middendorf. „DigitPro – Digital Prototype Build-up Using the Example of a Braided Structure.” IMTC, 2015
33DigitPro - J. Dittmann, P. Middendorf
Classical way of FEM filling simulation.
CHALLENGES IN DIGITPRO AND IN THE WORLD
J. Dittmann, P. Böhler, D. Michaelis, M. Vinot, C. Liebold, F. Fritz, H. Finckh, P. Middendorf. „DigitPro – Digital Prototype Build-up Using the Example of a Braided Structure.” IMTC, 2015
44DigitPro - J. Dittmann, P. Middendorf
� How to predict permeability values of near-net-shape
parts with varying fibre orientations ?
� What to do with big variations in permeability results ?
� How to validate permeability values if we don‘t know
what is right ?
[1] D. May, A. Aktas and A. Yong, International Benchmark Exercises on Textile Permeability and Compressibility Characterization, ECCM, 2018
[1]
THE PLAN
J. Dittmann, P. Böhler, D. Michaelis, M. Vinot, C. Liebold, F. Fritz, H. Finckh, P. Middendorf. „DigitPro – Digital Prototype Build-up Using the Example of a Braided Structure.” IMTC, 2015
55DigitPro - J. Dittmann, P. Middendorf
Predictmicroscopic yarn
permeability
Predictmesoscopic dual-scale permeability
Simulatemacroscopic partswith mesoscopicfilling behaviour
Multi-Scale Fiber
Architecture &
Flow Simulation
MULTI-SCALE FIBRE ARCHITECTURE
J. Dittmann, P. Böhler, D. Michaelis, M. Vinot, C. Liebold, F. Fritz, H. Finckh, P. Middendorf. „DigitPro – Digital Prototype Build-up Using the Example of a Braided Structure.” IMTC, 2015
77DigitPro - J. Dittmann, P. Middendorf
How to model micro/meso textile architecture ?
Unit cell-Level(RVE – Preform)
TexGen
RVE-Level(RVE - Fibre)
Open-
FOAM
PAM-CRASH
LS-DYNAPart-Level
(Near-net-shape)
IFB IFB
IFBIFB
MICROSCOPIC FIBRE ARCHITECTURE
J. Dittmann, P. Böhler, D. Michaelis, M. Vinot, C. Liebold, F. Fritz, H. Finckh, P. Middendorf. „DigitPro – Digital Prototype Build-up Using the Example of a Braided Structure.” IMTC, 2015
88DigitPro - J. Dittmann, P. Middendorf
Yarn permeability (perpendicular)
RVE-Level(RVE - Infiltration)
Open-
FOAM Ktrans
Yarn permeability (longitudinal)
TRANSFER TO MESOSCOPIC FIBRE ARCHITECTURE
J. Dittmann, P. Böhler, D. Michaelis, M. Vinot, C. Liebold, F. Fritz, H. Finckh, P. Middendorf. „DigitPro – Digital Prototype Build-up Using the Example of a Braided Structure.” IMTC, 2015
99DigitPro - J. Dittmann, P. Middendorf
How to implement yarn permeability ?
Unit cell-Level(RVE – Infiltration)
Open-
FOAM
Microscopic yarn permeability valuesRVE-Level(RVE - Infiltration)
� � ��
���
���
�
d:Darcy coefficient
�: Porosity
Kxyz: Permeability
IFB IFB
TRANSFER TO MESOSCOPIC FIBRE ARCHITECTURE
J. Dittmann, P. Böhler, D. Michaelis, M. Vinot, C. Liebold, F. Fritz, H. Finckh, P. Middendorf. „DigitPro – Digital Prototype Build-up Using the Example of a Braided Structure.” IMTC, 2015
1010DigitPro - J. Dittmann, P. Middendorf
Dual Scale Flow – How does it work in OpenFoam?
Inter tow flow
Inter tow flow + Intra tow flow = Dual scale flow
IFB
IFB
TRANSFER TO MESOSCOPIC FIBRE ARCHITECTURE
J. Dittmann, P. Böhler, D. Michaelis, M. Vinot, C. Liebold, F. Fritz, H. Finckh, P. Middendorf. „DigitPro – Digital Prototype Build-up Using the Example of a Braided Structure.” IMTC, 2015
1111DigitPro - J. Dittmann, P. Middendorf
Unit cell-Level(RVE – Infiltration)
Microscopic yarn permeability valuesRVE-Level(RVE - Infiltration)
PAM-CRASH
LS-DYNAPart-Level
(Near-net-shape) IFBIFB
THE USE OF PROCESS SIMULATION FOR FIBRE MODELING
Local fibre angle orientationDetachment
Gaps
Mesoscopic braiding simulation
J. Dittmann, P. Böhler, D. Michaelis, M. Vinot, C. Liebold, F. Fritz, H. Finckh, P. Middendorf. „DigitPro – Digital Prototype Build-up Using the Example of a Braided Structure.” IMTC, 2015
1212DigitPro - J. Dittmann, P. Middendorf
IFB
IFB
THE PLAN
J. Dittmann, P. Böhler, D. Michaelis, M. Vinot, C. Liebold, F. Fritz, H. Finckh, P. Middendorf. „DigitPro – Digital Prototype Build-up Using the Example of a Braided Structure.” IMTC, 2015
1313DigitPro - J. Dittmann, P. Middendorf
Predictmicroscopic yarn
permeability
Predictmesoscopic dual-scale permeability
Simulatemacroscopic partswith mesoscopicfilling behaviour
NUMERICAL PERMEABILITY PREDICTION
J. Dittmann, P. Böhler, D. Michaelis, M. Vinot, C. Liebold, F. Fritz, H. Finckh, P. Middendorf. „DigitPro – Digital Prototype Build-up Using the Example of a Braided Structure.” IMTC, 2015
1414DigitPro - J. Dittmann, P. Middendorf
Filling front, inlet variations, pressure field, etc. fast predictable & practicable
MAPPING
IFB IFB
NUMERICAL PERMEABILITY PREDICTION
J. Dittmann, P. Böhler, D. Michaelis, M. Vinot, C. Liebold, F. Fritz, H. Finckh, P. Middendorf. „DigitPro – Digital Prototype Build-up Using the Example of a Braided Structure.” IMTC, 2015
1515DigitPro - J. Dittmann, P. Middendorf
A characteristic micro/meso simulation with a macroscopic mesh
Effect of porous yarns in flow simulation
IFB
IFBIFB
NUMERICAL PERMEABILITY PREDICTION
J. Dittmann, P. Böhler, D. Michaelis, M. Vinot, C. Liebold, F. Fritz, H. Finckh, P. Middendorf. „DigitPro – Digital Prototype Build-up Using the Example of a Braided Structure.” IMTC, 2015
1616DigitPro - J. Dittmann, P. Middendorf
Porous yarns decrease the overall flow velocity and therfore the permeability values
Mean permeability value:• K̅1layer_sHM_nns_braid = 9.26e-8 m2 (without porous yarns)• K̅1layer_sHM_nns_braid_porous = 1.41e-8 m2 (with porous yarns)
Effect of porous yarns in flow simulation
t = 95 s
tp = 154 s
AFTER DIGITPRO – NEW WAY OF FEM FILLING SIMULATION
1818
J. Dittmann, S. Hügle, P. Middendorf. „NUMERICAL 3D PERMEABILITY PREDICTION USING COMPUTATIONAL FLUID DYNAMICS”, FPCM13 Kyoto, Japan, 2016
Dittmann, J., Hügle, S., Seif, P., Kauffmann L. and Middendorf, P., Permeability Prediction Using Porous Yarns in a Dual-Scale Simulation with Openfoam, ICCM21 - 21st International Conference on Composite Materials, Xi'an, China, Aug 2017
DigitPro - J. Dittmann, P. Middendorf
IFB
IFB
IFB
IFB
OUTLOOK
Improvements
2020DigitPro - J. Dittmann, P. Middendorf
� Transfer multi-scale approach to other processes (wet moulding,
APP, TFP, Pultrusion)
� Handle simulation challenges (meshing, post-processing)
� Simulate void formation and void transportIFB
Questions & Discussion
Institut für FlugzeugbauUniversität StuttgartPfaffenwaldring 3170569 Stuttgart
Dipl.-Ing. Jörg Dittmann