This study presents the development of a constitutive model for in-plane mechanical
behavior of five styles of plain woven Kevlar fabrics impregnated with silica
nanoparticles. The neat fabrics differed in fiber type, yarn count, denier, weave
tightness and strength, and varying proportions (4, 8, 16 and 24% by weight)
of nanoparticles were added to enhance the mechanical properties of the
fabric. It was found that fabrics impregnated with nanoparticles exhibit
significant improvement in shear stiffness and a slight increase in tensile
stiffness along the yarn directions over their neat counterparts. A constitutive
model was developed to characterize the nonlinear anisotropic properties of
nanoparticle-impregnated fabrics undergoing large shear deformation. The
parameters for the model were determined based on uniaxial (along yarn directions)
and
off-axis tension tests. This model was incorporated in the commercial FEA software
ABAQUS through a user-defined material subroutine to simulate various load cases.
Keywords
Kevlar fabric, soft armor, nanoparticle, constitutive model