Molecular orbital studies of polyethylene deformation

Crist, Buckley; Hereña, Peter G.

doi:10.1002/(sici)1099-0488(199602)34:3<449::aid-polb5>3.0.co;2-o

Cited by 34 publications

(38 citation statements)

References 4 publications

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“…This could be attributed to the low strain rate used in the experiments as well as other factors associated with the experimental fibers including the random orientation of crystals and different microstructural and topological defects. For PE, the axial modulus of 257 GPa in the Zdirection obtained from the present simulation is comparable with the experimental and simulation results, which are in the range of 235-300 GPa, reported in the literature [25,[43][44][45]. The axial modulus of PE reported by O'Connor et al [25] from MD simulation is 258 GPa, which is in excellent agreement with the present simulation value.…”

Section: Mechanical Properties Of the Virgin Crystalsmentioning

confidence: 79%

Molecular Dynamics Modeling of the Effect of Axial and Transverse Compression on the Residual Tensile Properties of Ballistic Fiber

Chowdhury

Sockalingam

Gillespie

2017

Fibers

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Ballistic impact induces multiaxial loading on Kevlar ® and polyethylene fibers used in protective armor systems. The influence of multiaxial loading on fiber failure is not well understood. Experiments show reduction in the tensile strength of these fibers after axial and transverse compression. In this paper, we use molecular dynamics (MD) simulations to explain and develop a fundamental understanding of this experimental observation since the property reduction mechanism evolves from the atomistic level. An all-atom MD method is used where bonded and non-bonded atomic interactions are described through a state-of-the-art reactive force field. Monotonic tension simulations in three principal directions of the models are conducted to determine the anisotropic elastic and strength properties. Then the models are subjected to multi-axial loads-axial compression, followed by axial tension and transverse compression, followed by axial tension. MD simulation results indicate that pre-compression distorts the crystal structure, inducing preloading of the covalent bonds and resulting in lower tensile properties.

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Section: Mechanical Properties Of the Virgin Crystalsmentioning

confidence: 79%

Molecular Dynamics Modeling of the Effect of Axial and Transverse Compression on the Residual Tensile Properties of Ballistic Fiber

Chowdhury

Sockalingam

Gillespie

2017

Fibers

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“…The Young modulus from the most recently reported ab initio calculation is 300 GPa. 2 The value from our single chain approach at room temperature density is 320 GPa, this is about 7% larger. The calibrated semiempirical data (349 GPa 4 and 343 GPa 5 ) are about 9% larger than our result.…”

Section: Discussionmentioning

confidence: 99%

Young Modulus of Crystalline Polyethylene from ab Initio Molecular Dynamics

et al. 1997

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The Young modulus for crystalline polyethylene is calculated using ab initio molecular dynamics based on density functional theory in the local density approximation (DFT-LDA). This modulus, which can be seen as the ultimate value for the Young modulus of polyethylene fibers, is found to be 334 GPa. For the first time the modulus is evaluated ab initio (no bias from experimental data) with demonstrated basis set convergence.

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“…The modulus Y z is the Young's modulus along the polymer chain. For comparison, our calculated LDA and GGA Young's modulus with the previous theoretical 16,26,[43][44][45][46][47] and experimental 48 -51 results are listed in Table III. Generally, the theoretical modulus are 10%-20% larger than the experimental modulus.…”

Section: Young's Modulusmentioning

confidence: 99%

Density functional calculations on the structure of crystalline polyethylene under high pressures

Miao

Zhang

Doren

et al. 2001

The Journal of Chemical Physics

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Structural and vibrational properties of solid nitromethane under high pressure by density functional theory J. Chem. Phys. 124, 124501 (2006); 10.1063/1.2179801 This article is copyrighted as indicated in the article. Reuse of AIP content is subject to the terms at: http://scitation. The geometrical structures of the crystalline polyethylene under several different external pressures up to 10 GPa are optimized by a pseudopotential plane wave density functional method. Both local density ͑LDA͒ and generalized gradient ͑GGA͒ approximations for exchange-correlation energy and potential are used. It is found that LDA heavily underestimate the geometry parameters under ambient pressure but GGA successfully correct them and get results in good agreements with the experimental geometry. The calculated GGA volume is about 94 Å 3 in comparison with the x-ray scattering value of about 92 Å 3 and the neutron scattering value of 88 Å 3 . The bulk and Young's modulus are calculated by means of several different methods. The Young's modulus along the chain ranges from about 350 to about 400 GPa which is in good agreement with the experimental results. But the bulk modulus is several times larger than those of experiments, indicating a different description of the interchain interactions by both LDA and GGA. The band structures are also calculated and their changes with the external pressure are discussed.

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Molecular orbital studies of polyethylene deformation

Cited by 34 publications

References 4 publications

Molecular Dynamics Modeling of the Effect of Axial and Transverse Compression on the Residual Tensile Properties of Ballistic Fiber

Molecular Dynamics Modeling of the Effect of Axial and Transverse Compression on the Residual Tensile Properties of Ballistic Fiber

Young Modulus of Crystalline Polyethylene from ab Initio Molecular Dynamics

Density functional calculations on the structure of crystalline polyethylene under high pressures

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