Robert J Young Stephen J Eichhorn, James A Bennett, Prasad Potluri NW Composites Centre, School of Materials, University of Manchester, UK Richard J Davies ESRF, Grenoble, France CHARACTERISATION OF THE MICROSTRUCTURE AND DEFORMATION OF WOVEN COMPOSITES
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CHARACTERISATION OF THE MICROSTRUCTURE AND ......Outline • Synchrotron microfocus X-ray diffraction • Deformation of single aramid fibres • Cross-ply laminate - microstructure
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Robert J YoungStephen J Eichhorn, James A Bennett, Prasad Potluri
NW Composites Centre, School of Materials, University of Manchester, UK
Richard J DaviesESRF, Grenoble, France
CHARACTERISATION OF THE MICROSTRUCTURE AND DEFORMATION
OF WOVEN COMPOSITES
Outline• Synchrotron microfocus X-ray diffraction
• Deformation of single aramid fibres
• Cross-ply laminate
- microstructure
- local fibre deformation
• Characterisation of the microstructure of woven composites
Probing the internal geometry of a woven composite during deformation using an x-ray micro-diffraction imaging techniqueRichard J. Davies, Christian Riekel, James A. Bennett, Stephen J. Eichhorn, and Robert J. YoungApplied Physics Letters, (2007) 91:044102.
Determination of Out-of-plane Fibre Tilt
0º-15º +15º
CCDCamera
FibreTow
Synchrotron x-ray beam
2 μm diameter (λ = 0.1 nm)
006
Calibration of Out-of-plane Tilt Angle
-10 -5 0 5 100.0
0.2
0.4
0.6
0.8
1.0
Inte
nsity
Rat
io (0
06bo
ttom/0
06to
p)
Tilt angle (o)
-10 -5 0 5 100
500
1000
1500
2000
2500
3000
3500
4000
Inte
nsity
(arb
)
Tilt angle (o)
006 (bottom) 006 (top)
Measure the relative intensity of the top and bottom 006 Bragg reflections as a function of out-of plane tilt angle
Mapping Fibre Orientation and AlignmentWoven Aramid Satin Weave with Hole Drilled
Out-of-plane fibre tilt angle
Vertical tows
Horizontal tows
Woven Aramid Satin Weave with Hole Drilled
Changes in out-of-plane tilt angle
Tiltincreases
Tiltdecreases
Stress
In-plane fibre orientation
Horizontal tows
Vertical tows
Fibre orientation affected by hole
Development of axial fibre stress
Horizontal tows
Vertical tows
Woven Aramid Satin Weave with Hole Drilled
Development of axial fibre stressStress
Conclusions
• Microfocus x-ray diffraction allows on the micron level:- the evaluation of local composite geometry- the determination of local fibre stress
• Tremendous scope for further analysis and exploitation:- cross-ply aramid/epoxy- woven aramid/epoxy
Acknowledgements
• EPSRC – funding of the research project• Dr. D. J. Bannister of SP Systems Ltd for supplying the materials
Development of Fibre Stress during Deformation
Transverse fibres
• Non-uniform stress distribution• Complex stress distribution around the hole
Development of Axial Fibre Stress
• Only stresses remote from the hole• Initial residual compression in both plies• Transverse fibres go further into compression