Mean fiber fragment length

Debond length and mean fiber fragment length... 

From Eqs. (4.45) and (4.46), the solutions for the mean fiber fragment length are derived... 

Fig, 4,9, Comparisons of mean fiber fragment length, 2L, as a function of applied stress, (t, between experiments and theory for carbon fiber-epoxy matrix composites with (a) XAl fiber and (b) XAIOO fiber ( ) experiment (---------) prediction (..) debond length. After Zhou ct al. (1995a, b). 

Having satisfied the requirements for full bonding, the mean fiber fragmentation length, 2L, is determined from Eq. (4.72)... 

Fig. 4.12. Varialion of mean fiber fragment length, 2L, versus applied strain, t, in the full bonded interface model (---------) varying ctts(22,) (------------) constant fiber tensile strength ctts- After Kim et al. (1993b).

Finally, the solution for the mean fiber fragmentation length, IL, which is the sum of the debonded and bonded lengths in the partial debond model, is derived from the fiber fragmentation criterion given by Eq. (4.70)... 

Taking the approximate values for the non-dimensional coefficients given in Eq. (4.80), the solution for the mean fiber fragment length, 2L, is given in a closed form equation... 

The mean fiber fragment length, 2L, is plotted as a function of the applied strain, e, in Fig. 4.18. Similar to the results for the fully bonded interface model shown in Fig. 4.12, the full frictional interface model predicts that (2L) decreases sharply with increasing applied strain within a short range of c. A high fiber tensile strength... 

The only alternative approaches for evaluating Sc, known to the authors, are based on pull-out and fragment length measurements.46 Both quantities depend on Sc and m, as well as r. Consequently, if r is known, Sc can be determined. For example, m can be evaluated by fitting the distribution of fiber pull-out lengths to the calculated function. Then, Sc can be obtained for the mean value, h, using Eqn. (12). This approach has not been extensively used and checked. 

Another test method for resin-fiber bond strength employs a single fiber embedded within a long resin bar (154). As the bar is stretched, the less-extensible fiber breaks into smaller and smaller fragments with a final mean length of / Originally, T was interpreted in terms of a characteristic failure stress Ug of the resin-fiber bond in shear (155) ... 

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