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Advances in Materials Science and Engineering
Volume 2013, Article ID 329549, 15 pages
http://dx.doi.org/10.1155/2013/329549
Research Article

Axial-Compressive Behavior, Including Kink-Band Formation and Propagation, of Single p-Phenylene Terephthalamide (PPTA) Fibers

1Department of Mechanical Engineering, Clemson University, Clemson, SC 29634-0921, USA
2Army Research Laboratory, Weapons & Materials Research Directorate, Proving Ground, Aberdeen, MD 21005-5069, USA

Received 21 May 2013; Revised 15 July 2013; Accepted 17 July 2013

Academic Editor: Gongnan Xie

Copyright © 2013 M. Grujicic et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The mechanical response of p-phenylene terephthalamide (PPTA) single fibers when subjected to uniaxial compression is investigated computationally using coarse-grained molecular statics/dynamics methods. In order to construct the coarse-grained PPTA model (specifically, in order to define the nature of the coarse-grained particles/beads and to parameterize various components of the bead/bead force-field functions), the results of an all-atom molecular-level computational investigation are used. In addition, the microstructure/topology of the fiber core, consisting of a number of coaxial crystalline fibrils, is taken into account. Also, following our prior work, various PPTA crystallographic/topological defects are introduced into the model (at concentrations consistent with the prototypical PPTA synthesis/processing conditions). The analysis carried out clearly revealed (a) formation of the kink bands during axial compression; (b) the role of defects in promoting the formation of kink bands; (c) the stimulating effects of some defects on the fiber-fibrillation process; and (d) the detrimental effect of the prior compression, associated with fiber fibrillation, on the residual longitudinal-tensile strength of the PPTA fibers.