Multiscale modeling of high-strength fibers and fabrics

Using a combination of electronic structure calculations, molecular dynamics simulations, and finite-element analysis, we examine the physical mechanisms governing the performance of Kevlar (R)/carbon composite fibers over a variety of length scales. To begin, we use electronic structure calculations to examine the molecular structure of Kevlar polymers, and quantitatively compare the intramolecular interactions to the non-bonded intermolecular interactions. We then quantify the potential energy landscape between polymers, and fit this data to a potential function for use in molecular dynamics simulations. From molecular dynamics simulations, we calculate the stiffness and elastic modulus of pristine Kevlar fibrils and Kevlar/carbon composite fibrils. We then use a finite-element model of Kevlar fabric to examine how changes in the mechanical properties of the fibers affect the ballistic response of the fabric. These findings provide insight into how carbon fragments, which influence the nanostructure of the polymer, can enhance the ballistic performance of Kevlar fabric layers.