The Effect of Plain-Weaving on the Mechanical Properties of Warp and Weft P-Phenylene Terephthalamide (PPTA) Fibers/Yarns

Abstract

Coarse-grained molecular statics/dynamics methods are first used to investigate degradation in the PPTA fiber/yarn tensile strength, as a result of the prior compressive or tensile loading. PPTA fibers/yarns experience this type of loading in the course of a plain-weaving process, the process which is used in the fabrication of ballistic fabric and flexible armor. The more common all-atom molecular simulations were not used to assess strength degradation for two reasons: (a) the size of the associated computational domain rendering reasonable run-times would be too small and (b) modeling of the mechanical response of multi-fibril PPTA fibers could not be carried out (again due to the limited size of the computational domain). However, all-atom simulations were used to (a) define the coarse-grained particles (referred to as beads ) and (b) parameterize various components of the bead/bead force-field functions. In the second portion of the work, a simplified finite-element analysis of the plain-weaving process is carried out in order to assess the extent of tensile-strength degradation in warp and weft yarns during the weaving process. In this analysis, a new material model is used for the PPTA fibers/yarns. Specifically, PPTA is considered to be a linearly elastic, transversely isotropic material with degradable longitudinal- tensile strength and the longitudinal Young s modulus. Equations governing damage and strength/stiffness degradation in this material model are derived and parameterized using the coarse-grained simulation results. Lastly, the finite-element results are compared with their experimental counterparts, yielding a decent agreement.

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Document Details

Document Type
Technical Report
Publication Date
Aug 15, 2014
Accession Number
ADA622414

Entities

People

  • Bryan A. Cheeseman
  • Chianfong Yen
  • J. S. Snipes
  • M. Grujičić
  • R. Yavari
  • S. Ramaswami

Organizations

  • United States Army Research Laboratory

Tags

Communities of Interest

  • Energy and Power Technologies
  • Weapons Technologies

DTIC Thesaurus Topics

  • Computational Science
  • Dynamics
  • Fabrication
  • Finite Element Analysis
  • Material Degradation Processes
  • Materials
  • Materials Processing
  • Mechanical Engineering
  • Mechanical Properties
  • Mechanical Working
  • Mechanics
  • Modulus Of Elasticity
  • Molecular Dynamics
  • Particles
  • Simulations
  • Stiffness
  • Tensile Strength

Readers

  • Computational Modeling and Simulation
  • Quantum Chemistry
  • Reinforced Composite Materials