Fragmentation in a Model Two-Component Fibrous Structure

A simple micromechanical model for the deformation of an isolated fiber fragment embedded within a bundle of continuous filaments is used to study progressive fragmentation of the low elongation-to-break (LE) fiber component during extension of a model two-component fibrous structure. The model structure, representing a blended yarn or cord, is realized in experimental specimens by helically wrapping a number of high elongation-to-break (HE) components around a straight central LE component; polyester sewing thread and cotton sewing thread are used is this work as the HE and LE components, respectively. The concept of a characteristic fragment length, involving the failure statistics of a fragment as influenced by the interaction forces between the fragment and the surrounding fibrous medium, is used to interpret the fragmentation experiments and calibrate a dimensionless parameter in the micromechanical model. The calibrated model is shown to provide insight into force interactions between the fragment and the surrounding structure. Bounds are established on the force interaction behavior associated with possible variations in the value of a constitutive parameter.