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Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 1 ANALYSIS OF A SHEAR.

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Presentation on theme: "Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 1 ANALYSIS OF A SHEAR."— Presentation transcript:

1 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 1 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

2 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 2 Aim: Understanding and modeling the multi-scale behavior of materials Model identification (coupons) and validation (mock-ups) EXPERIMENT / SIMULATION INTERACTIONS

3 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 3 Testing machines Tested objects Strains obtained by: experiment? computation?

4 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 4 Material Model and identification Shear test Conclusion

5 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 5 Some applications of Sepcarb ®

6 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 6 Unidirectional or woven plies of ex-PAN fibers (preoxyded) + Ex-PAN fiber mat (preoxydised) Unidirectional or woven plies of HR Carbon fibers + Ex-PAN fiber mat (preoxydised) Yarns, unidirectional or woven plies of continuous or non-continuous HR Carbon fibers Preform manufacture (Stacking + Needling) Carbonization Pyrolysis (>1000°C) Chemical vapor infiltration Novoltex ® Skinex ® Multirex ® Needled laminates [Cavalier] HR Carbon Fibers HM Carbon Fibers

7 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 7 Carbon matrix stacked +needled Layers of continuous fibers X Layers of non-continuous fibers Y and/or C/C reinforced laminate Carbon preform + Some preforms … Plane preforms made of non-continuous fibers Needling Unidirectional layers Satin layers

8 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 8 satin layers 10 mm Multirex ® family Macro-undulations (scale: n plies) ~1.5 mm ~3 mm unidirectional plies No-undulation (scale: coupon) Meso-undulations (scale: ply) 1.5 mm 0.5 mm

9 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 9 Tension/compression tests at 0° and 45° on a [0 y,90 y ]n satin Non linear for tension test in non-continuous fiber direction Non linear for 45° test Linear in continuous fiber direction Multirex ® behavior Stress (MPa)

10 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 10 Model for a family of materials Uniaxial tests Displacement and strain field measurement Validation on a set of composites Identification procedure Biaxial tests

11 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 11 Material Model and identification Shear on C/C Composites Conclusion

12 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 12 Meso-constituents Layers of continuous fibers Layers of non-continuous fibers Models X 2 damage parameters: d 2 and d 12 Transverse tension compression Y 3 damage parameters: d 2 and d 12 + d 1 (in fiber direction) Transverse tension compression Fiber direction tension compression Hybrid laminate Kinetics of damage: gradual or brittle (rupture of fibres) Model designed for a family of materials Damage meso-model

13 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 13 State: damaged material strain energy d i = piecewise constant (meso level) mechanism?crack openingcrack closure : positive part of °: initial value of Mechanisms: friction and incomplete-closure of cracks Plasticity model with isotropic hardening Inelasticity Anisotropic damage theory [Lad 83] Kinetics: Associated forces: Energy-release rateEffective stress d 1 (,, ) d 12 or 2 (, +b )

14 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 14 Elastic parameters: 2 tensile tests on a hybrid [0x,90y]n Damage kinetics: 2 tensile tests on a [0y,90y]n satin Elastic longi. and transverse energy d 12 (Y d 12 ) kinetics d 1 (Y d 1 ) kinetics Hyp: d 12 and d 2 linked 0° tension test Elastic shear energy Hyp: no change in d 1 45° tension test

15 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 15 0° tension test on a [0y,90y]n satin Laminate 0y0y 90 y Loading d 1 d 12 d 2 Plies Plastic strains Stress (MPa) Test Simulation Mean L. Strain (%) Mean T. Strain (%) Simulation tool: classical laminate theory in the non-linear field

16 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 16 Material Model and identification Shear test Conclusion

17 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 17 [0 y,90 y ] n C/C Composites Uniaxial tests Biaxial tests Comparison between experiment/simulation Heterogeneous strains Gages Strain fields CORRELI LMT [Hild, Périé & Coret, 1999]

18 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 18 Video digital camera + ICPCI bus + PC Resolution : > 1Mpixels Coding : 8-12 bits File format :.bmp,.tiff,.jpeg… Interchangeable lenses Digital camera Argentic camera or video camera + scanner Scanning Electron Microscope... Tensile machine CARDAN joint Long distance microscope CCD video camera PC C/C specimen

19 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 19 Principle of image correlation Displacement Scale of study: (only depends on magnification and pattern) t0t0 t icro 0.4mm meso Macro

20 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 20 Principle of correlation: displacement of 1D signal x d d-Ad+A Correlation product: g*f d f g ggg x+A x g Signal (FFT) )()()*(gFFTf gf

21 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 21 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 Algorithm: CORRELI LMT Reference image (t 0 )Deformed image (t) Reference ZOIShifted ZOI V U FFT Correlation (precision: pixel) Max. Sub-pixel displacement ( U, V) Yes No Yes

22 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 22 Shear test on [0 y,90 y ] n C/C Composite (SEPCARB ® ) 10 mm Macro-undulation (random distribution) 100 mm Fibres

23 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 23 ASTREE: Triaxial testing machine Image Acquisition Control Optical strain field measurement

24 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 24 Loading (elastic FEA) Specimen: plateBoundary conditions: displacements

25 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 25 Validation of geometry: shear damage in a ply FEA + Damlam [Clu 01]

26 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 26 Gauges Artificial speckle Surface displacement field Experimental boundary conditions x 30

27 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 27 8-bit signal - Size of ZOI: 64 pixels - ZOI shift: 32 pixels Practical Precision (strain) ~10 -4 DIC Gauge 0.2% Strain (%) Time (s) 0.2%

28 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 28 CORRELI 2D FEA Displacement field Strain field N°11 N°6N°1 Material heterogeneities ? Boundary conditions

29 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 29 Ply Shear damage d 12 CORRELI 2D Damlam Strain: Damage: CORRELI 2D FEA Damlam Strain: Damage: Coupling

30 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 30 Ply CORRELI 2D FEA Damlam Strain: Damage: Fiber damage d 1 CORRELI 2D Damlam Strain: Damage: Coupling

31 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 31 Brittle failure

32 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 32 Displacement field measurement (CORRELI LMT ) Experimental strain field (CORRELI LMT ) Computation (FEA) of strain field with experimental boundary conditions Evaluation of damage state: Damlam ? ? Brittle failure Distributed shear damage (YET THERE ARE DEFECTS) Onset of fiber damage

33 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 33 Material Model and identification Shear on C/C Composites Conclusion

34 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 34 Meso model Specific identification procedure 1 stacking sequence 2 meso constituents Model implemented in Damlam Mock-up design

35 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 35 Experiment / Simulation coupling Displacement field measurement Multiaxial experiment (mock-up) Experiment interpretation by using the material model

36 Applications of Optical Techniques Analysis of a shear test on a C/C composite by using digital image correlation and a damage model 36 Understanding and modeling the multi-scale behavior of (composite) materials Measurement of fields (DIC) (texture = tracer) Numerical simulations Control of test Real-time simulation Multi-scale measurement Resolution of CCD cameras Inverse identification


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