Finite Element Modeling Of Ballistic Penetration into Fabric Armor
The goal of this work is to analyze the ballistic performance of plain woven fabric used in soft armor systems using a detailed finite element analysis at yarn level. As more complex materials systems are introduced in engineering practice, the design engineer faces the dilemma of utilizing homog...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2006
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/5457/1/ITMA_2006_5.pdf |
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| Summary: | The goal of this work is to analyze the ballistic performance of plain woven fabric
used in soft armor systems using a detailed finite element analysis at yarn level. As
more complex materials systems are introduced in engineering practice, the design
engineer faces the dilemma of utilizing homogenization techniques or detailed
numerical models. The latter offers a number of advantages, such as the ability to
introduce separate constitutive laws and failure criteria for each phase, at the expense
of computation cost. This is particularly important in ballistic performance of the soft
armor where the projectile-fabric interaction and failure modes are complicated and
can not be realized in other approaches.
An automatic geometry generation algorithm for textile is developed that can
generate complex fabric geometries spanning several unit cells. This program
(named DYNTEX) based on the mentioned algorithm is designed using MATLAB
code. A commercial finite element code named LS-DYNA is used as the solver and
DYNTEX program is then extended to do the pre-processing for LS-DYNA. Four types of projectile shapes were chosen which consist of spherical, blunt,
conical, hemi-spherical and a conically cylindrical military sized bullet. An
orthotropic material with von-Mises stress at failure of 2.7GPa was chosen for
material behavior of yarns. Since projectiles did not have considerable deformation,
they assumed as rigid bodies. Furthermore a general surface to surface contact was
selected for the contact between the yarns and projectile-fabric. Initial conditions and
results of experimentations were extracted from literature to validate the simulation
results for different projectile shapes.
To verify the mesh built by DYNTEX program a relatively low velocity impact
simulation performed in oblique angle. Then convergence analysis is then carried out
by changing the mesh density of fabric target and it was shown primary mesh density
was fine enough to start the remaining simulations.
Finite element models of fabric impact were made with initial conditions extracted
from literature and simulations were performed. The results of simulations showed
close agreement with experimental tests. Moreover several parameters which affect
the energy absorption of fabric were studied. These parameters were friction,
boundary conditions, projectile nose diameter and projectile nose angle. The
mentioned parameters were studied with respect to several projectile nose shapes and
boundary conditions. |
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