Geometrically necessary strand loss

From the microscopic picture for the craze growth it seems clear that one important microscopic variable must be the mean number n of entangled strands within each fibril which survive the geometrically necessary strand loss associated with the interface formation. If the number of such strands is zero, the fibril will fail, since the polymer fluid which flows from the active zone into the fibril has no strain hardening capability and will not be able to support the relatively high tensile stresses necessary to propagate the interface. To obtain n one first estimates n, the total number of strands in the undeformed phantom fibril from which a craze fibril is drawn and which is given by ... 

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