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ANALYSIS OF A SHEAR TEST ON A C/C COMPOSITE BY
USING DIGITAL IMAGE CORRELATION AND A DAMAGE
MODEL J.-N. Périé, S. Calloch, C. Cluzel and
F. Hild
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Aim Understanding and modeling the multi-scale
behavior of materials
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Testing machines Tested objects
Strains obtained by experiment? computation?
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Material Model and identification Shear
test Conclusion
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Some applications of Sepcarb
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Needled laminates Cavalier
Novoltex
Skinex
Multirex
Unidirectional or woven plies of ex-PAN fibers
(preoxyded) Ex-PAN fiber mat (preoxydised)
Yarns, unidirectional or woven plies
of continuous or non-continuous HR Carbon fibers
Unidirectional or woven plies of HR Carbon fibers
Ex-PAN fiber mat (preoxydised)
Preform manufacture (Stacking Needling)
Carbonization Pyrolysis (gt1000C)
Chemical vapor infiltration
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C/C reinforced laminate
Layers of continuous fibers X
Carbon matrix
Carbon preform

stacked needled
and/or
Layers of non-continuous fibers Y
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Multirex family
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Multirex behavior
Linear in continuous fiber direction
Tension/compression tests at 0 and 45 on a
0y,90yn satin
Stress (MPa)
Non linear for tension test in non-continuous
fiber direction Non linear for 45 test
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Model for a family of materials
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Material Model and identification Shear on C/C
Composites Conclusion
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Damage meso-model
Hybrid laminate
Kinetics of damage gradual or brittle (rupture
of fibres)
Model designed for a family of materials
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Anisotropic damage theory Lad 83
State damaged material strain energy
mechanism?
crack opening
crack closure
lt a gt positive part of a a initial value of
a
di piecewise constant (meso level)
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Elastic parameters 2 tensile tests on a hybrid
0x,90yn
d12(Yd12 ) kinetics
Elastic longi. and transverse energy
0 tension test
Hyp d12 and d2 linked
d1(Yd1 ) kinetics
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Laminate
0 tension test on a 0y,90yn satin
Simulation tool classical laminate theory in
the non-linear field
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Material Model and identification Shear
test Conclusion
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0y,90yn C/C Composites
Uniaxial tests
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Video digital camera ICPCI bus PC
Digital camera
Argentic camera or video camera scanner
Scanning Electron Microscope ...
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Principle of image correlation
t0
t
Scale of study (only depends on magnification
and pattern)
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Principle of correlation displacement of 1D
signal
Signal
f
x
d
Correlation product gf
x
d
d-A
dA
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Algorithm CORRELILMT
Reference image (t0)
Deformed image (t)
Choice of ZOI Pixel correlation Extraction of
Displaced zone Windowing FFT correlation
interpolation Sub-pixel displacement
increment FFT shift of displaced
zone Convergence? Total displacement
New zone?
Strain computation
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Shear test on 0y,90yn C/C Composite (SEPCARB)
Fibres
100 mm
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ASTREE Triaxial testing machine
Image Acquisition
Control
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Specimen plate
Boundary conditions displacements
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Validation of geometry shear damage in a ply
FEA Damlam Clu 01
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(No Transcript)
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8-bit signal - Size of ZOI 64 pixels - ZOI
shift 32 pixels
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Strain field
Displacement field
Boundary conditions
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Ply
Ply
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Ply
Ply
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Brittle failure
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Displacement field measurement (CORRELILMT)
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Material Model and identification Shear on C/C
Composites Conclusion
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Meso model
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Multiaxial experiment (mock-up)
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Understanding and modeling the multi-scale
behavior of (composite) materials