EFFECT OF TEXTURE ON FRACTURE OF FIBROUS MATERIALS

We present numerical results for the effect of orientation and placeme nt distribution of fibres on fracture processes in two-dimensional ran dom fibrous networks. As can be expected, highest elastic modulus and strength can be obtained with bundles of oriented fibres. However, suc h an enhancement is obtained only at a cost of reduced strain-to-failu re (i.e. the strain corresponding to the maximum in the stress-strain curve). We provide quantitative estimates of these effects and discuss micromechanical reasons for the observed differences in strength as w ell as in the number of failed connections prior to the macroscopic fr acture. Generally, the strength of the network was found to be a funct ion of the mean length [l(s)] of fibre segments-parts of fibres betwee n intersections with other fibres-whereas strain-to-failure apparently appears not to be affected by [l(s)], but to be determined by the for m of the segment length probability distribution. Finally, the form of the probability distribution for axial stresses is exponential indepe ndent of texture. (C) 1998 Elsevier Science S.A. All rights reserved.