Experimental Measurement and Computational Simulation of the Strains on a Single Yarn in a Kevlar Fabric During Stretching

Report No. ARL-TR-5224
Authors: Jian H. Yu, Brandon McWilliams, Peter G. Dehmer, and Chian-Fong Yen
Date/Pages: June 2010; 18 pages
Abstract: The ability to measure the strain on an individual yarn is essential for the understanding of mechanical properties of fabrics. Using a non-contact technique called photogrammetry, we investigate the deformation of a single yarn in a Kevlar┬┐ fabric as it undergoes stretching. Photogrammetry uses two charge-coupled device (CCD) cameras fitted with macro lenses to record stereo images of the fabric during stretching. We tracked the change in the arc length between a set of points and calculated the strain from the arc length at various locations. We used a finite element method (FEM) model to simulate the experiment, optimizing the material parameters in the FEM model by comparing the experimental data to the computational results. After optimization, the simulated displacement and strain time histories matched reasonably well with the experimental data.
Distribution: Approved for public release
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Last Update / Reviewed: June 1, 2010