Abstract
The size of the damage zone was determined on modified compact tension (CT) specimens of model composites containing a single layer of different textile fabrics by locating the acoustic emission (AE) events during loading. Among the reinforcing fabrics both crimped woven (co-woven and/or hybrid clothes) and non-woven (swirl mat) structures were studied. The extent of the damage zone was linked to a circle or ellipse in which a given proportion of the AE events could be found. Its size was strongly underestimated when only the stress-whitened zone at the crack tip, resolved by light microscopy, was considered. It is therefore reasonable to distinguish a processing zone (stress-whitened region) within the damage one. The size of the damage zone depended upon the microstructure of the reinforcing fabric due to differences in the possible stress transfer, as expected.
It was also shown that the stress transfer and stress distribution capability of the fabrics strongly depend on their “wettability” by the matrix polymer; easily impregnable fabrics are loosely structured and/or hybridized ones.
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