Multiscale modeling of high-strength fibers and fabrics

Thomas, John A.; Shanaman, Matthew T.; Lomicka, Christian L.; Boyle, Mike P.; Calderón‐Colón, Xiomara; LaBarre, E. D.; Tiffany, Jason E.; Trexler, Morgan

doi:10.1117/12.919395

Cited by 7 publications

(4 citation statements)

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“…For PPTA, the values obtained from simulations are compared to properties reported from previous experimental studies. ,,,, In general, the magnitude of strain rate-dependent mechanical properties can appear larger when computed by molecular simulation. This is because the inherently small time scales accessible by molecular simulation lead to very high strain rates (typically >10 8 s –1 ). ,,, For example, it was reported that the chain direction mechanical properties of PPTA increase with strain rate, ,,,, which is consistent with the results in Figure . This strain rate dependence has been attributed to the intermolecular slippage and plastic flow that occurs at low strain rates, resulting in more energy dissipation .…”

Section: Resultssupporting

confidence: 79%

Molecular Dynamics Simulation of the Stress–Strain Behavior of Polyamide Crystals

Yang

Stober

et al. 2021

Macromolecules

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Molecular dynamics simulations modeled the aramid poly(p-phenylene terephthalamide) (PPTA) and a related aromatic-aliphatic polyamide derived from a five-carbon aliphatic diacid (PAP5) with nine different reactive and non-reactive force fields. The force fields were evaluated based on crystal structures as well as intermolecular Hbonding and π-molecular interactions. The optimum force field was then used to simulate stress-strain behavior in the chain and transverse-to-chain directions. In the chain direction, PAP5 had higher ultimate stress and failure strain than PPTA; however, the stiffness of PAP5 was lower than PPTA at low strain (0-2%) while the reverse was observed at high strain (last 5% before failure). This contrast, and differences in the transverse direction properties, were explained by the methylene segments of PAP5 that confer conformational freedom, enabling accommodation of low strain without stretching covalent bonds. The simulation approach demonstrated here for two poly-1 Macromolecules 2021 10.1021/acs.macromol.1c00974 mers with distinct chemistry but similar atomic interactions may be extended to other polyamides.

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Section: Resultssupporting

confidence: 79%

Molecular Dynamics Simulation of the Stress–Strain Behavior of Polyamide Crystals

Yang

Stober

et al. 2021

Macromolecules

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“…Nonetheless, the trends reported here reflect limiting behavior and can be used to understand the effect of the alkyl chain length. In addition, the high strain rates of the simulations are necessitated by the inherently short time scale of the simulation method ,− and have been reported to result in higher predicted strength and modulus. This strain rate dependence has been attributed to the (in)commensurability between the rate of deformation and the frequency of molecular processes .…”

Section: Resultsmentioning

confidence: 99%

Effect of Aliphatic Chain Length on the Stress–Strain Response of Semiaromatic Polyamide Crystals

Yang

Stober

et al. 2022

Macromolecules

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Reactive molecular dynamics simulations were used to model poly(p-phenylene terephthalamide) and related aromatic-aliphatic polyamides derived from p-phenylene diamine and aliphatic diacids with different numbers of carbon atoms in the aliphatic chain (5, 6, 7, or 8). Tensile strain was applied to each polymer crystal in the chain direction and the mechanical response was characterized. All the polymers with aliphatic segments exhibited strain hardening, transitioning from an initial (low-strain) linear regime to a second (high-strain) linear regime. The modulus at high strain was similar for all polymers, but the modulus calculated at low strain decreased with increasing aliphatic chain length. The decrease in the low-strain modulus with increasing chain length was explained by the observation that polymers with longer aliphatic chains were wavier (i.e., deviated more from the fully extended conformation) in the quiescent 1 state such that they could accommodate low strain without deforming covalent bonds.Extension of wavy chains occurred through an intra-chain process for all polymers, quantified by the bond dihedral angles. In addition, for polymers with an even number of non-aromatic carbons, the strain response involved slip between chains within the hydrogen bonded sheets. The ultimate stress of the polymers exhibited an odd-even effect (even polymers were weaker) which was explained by differences in hydrogen bonding and ring-ring coplanarity prior to failure; polymers with an even number of carbon atoms had less favorable H-bonding and poorer ring alignment. The results revealed direct correlations between aliphatic chain length, intra-and inter-chain interactions, and the mechanical properties of polyamide crystals.

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“…Recently Mayo and Wetzel 193 studied the cut resistance and failure of single fibers and report significant deformation, delamination and progressive fibril failure of Kevlar fibers depending on the blade angle. Thomas et al 194 and Lomicka et al 195 used MD simulations to predict the properties of Kevlar fibrils. The MD models predicted higher elastic modulus in tension than the experimental values which they attributed to the lack of defects in the model.…”

Section: Fibril Length Scale Molecular Dynamics (Md) Modeling Of Ballmentioning

confidence: 99%

“…MD models not only provide insight into how molecular and fibril level properties may affect the fiber properties but also assist in designing materials with improved properties. For instance, Thomas et al 194 used fragments of CNTs along with Kevlar fibrils in their MD simulations and predicted a 10% higher tensile failure stress compared to a Kevlar only system. As discussed earlier inter-fibrillar shear is an important mechanism during nanoindentation and in energy absorption associated with particle-impregnated fabrics.…”

Section: Fibril Length Scale Molecular Dynamics (Md) Modeling Of Ballmentioning

confidence: 99%

Recent advances in modeling and experiments of Kevlar ballistic fibrils, fibers, yarns and flexible woven textile fabrics – a review

Sockalingam

Chowdhury

Gillespie

et al. 2016

Textile Research Journal

112

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Ballistic impact onto flexible woven textile fabrics is a complicated multi-scale problem given the structural hierarchy of the materials, anisotropic material behavior, projectile geometry-fabric interactions, impact velocity and boundary conditions. Although this subject has been an active area of research for decades, the fundamental mechanisms such as material failure, dynamic response, multi-axial loading occurring at the lower length scales during impact are not well understood. This paper reviews the recent advances in modeling and experiments of Kevlar ballistic fibrils, fibers, yarns and flexible woven textile fabrics pertinent to the deformation modes occurring during impact and serves to identify topics worthy of further investigation that will advance the basic understanding of the phenomena governing transverse impact. This review also explores on aspects such as homogeneous versus heterogeneous behavior of yarns consisting of individual fibers and the inelastic transverse behavior of the fiber which is not considered in the previous review papers on this topic.

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Multiscale modeling of high-strength fibers and fabrics

Cited by 7 publications

References 0 publications

Molecular Dynamics Simulation of the Stress–Strain Behavior of Polyamide Crystals

Molecular Dynamics Simulation of the Stress–Strain Behavior of Polyamide Crystals

Effect of Aliphatic Chain Length on the Stress–Strain Response of Semiaromatic Polyamide Crystals

Recent advances in modeling and experiments of Kevlar ballistic fibrils, fibers, yarns and flexible woven textile fabrics – a review

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