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Click on the different energy absorbing mechanisms to see how they operate




Click on the different energy absorbing mechanisms to see how they operate

Matrix Deformation

For tough matrices a high interfacial strength is desirable in order to favour matrix deformation. Conversely, for brittle matrices a low interfacial strength is desirable so that interfacial debonding, crack deflection, fibre fracture, and fibre pull-out can occur.

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Fibre Pull-out

Fibre Fracture
Interfacial Debonding
Displacement



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Crack Deflection




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Crack Deflection

The transverse stress at a crack tip in an axially loaded composite is roughly 20% of the axial stress and so crack deflection occurs if the interface strength is less than 20% of the fibre strength.
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Stress field approach
Axial stress at crack tip
Transverse stress at crack tip
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Crack Deflection   

Applied
load
generates
interfacial
shear stress
For a finite Weibull Modulus, there is a
finite probability that fibre fracture will
occur remote from the crack plane.
Fibre Strength Variation
Stress Distribution
Fibre fracture
probability
Fibre Fracture
Interfacial Debonding
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Crack deflection occurs if the energy release rate during interfacial debonding, Gi, exceeds the critical energy release rate, Gic, (interfacial fracture energy).
Energy approach