Modelling the damage and deformation process in a plastic bonded explosive microstructure under tension using the finite element method
File(s)COMMAT-D-15-00257R1.pdf (4.54 MB)
Accepted version
Author(s)
Arora, H
Tarleton, E
Li-Mayer, J
Charalambides, M
Lewis, D
Type
Journal Article
Abstract
Modelling the deformation and failure processes occurring in polymer bonded explosives (PBX)
and other energetic materials is of great importance for processing methods and lifetime storage
purposes. Crystal debonding is undesirable since this can lead to contamination and a reduction
in mechanical properties. An insensitive high explosive (PBX-1) was the focus of the study.
This binary particulate composite consists of (TATB) filler particles encapsulated in a polymeric
binder (KELF800). The particle/matrix interface was characterised with a bi-linear cohesive law,
the filler was treated as elastic and the matrix as visco-hyperelastic. Material parameters were
determined experimentally for the binder and the cohesive parameters were obtained previously
from Williamson et al. (2014) and Gee et al. (2007) for the interface. Once calibrated, the material
laws were implemented in a finite element model to allow the macroscopic response of the
composite to be simulated. A finite element mesh was generated using a SEM image to identify
the filler particles which are represented as a set of 2D polygons. Simulated microstructures
were also generated with the same size distribution and volume fraction only with the idealised
assumption that the particles are a set of circles in 2D and spheres in 3D. The various model
results were compared and a number of other variables were examined for their influence on the
global deformation behaviour such as strain rate, cohesive parameters and contrast between filler
and matrix modulus. The overwhelming outcome is that the geometry of the particles plays a
crucial role in determining the onset of failure and the severity of fracture in relation to whether
it is a purely local or global failure. The model was validated against a set of uniaxial tensile
tests on PBX-1 and it was found that it predicted the initial modulus and failure stress and strain
well.
Keywords: Particulate composites, High volume fraction, Finite Element Analysis,
Micromechanics, Fracture, PBX and Viscoelastic matrix composite
and other energetic materials is of great importance for processing methods and lifetime storage
purposes. Crystal debonding is undesirable since this can lead to contamination and a reduction
in mechanical properties. An insensitive high explosive (PBX-1) was the focus of the study.
This binary particulate composite consists of (TATB) filler particles encapsulated in a polymeric
binder (KELF800). The particle/matrix interface was characterised with a bi-linear cohesive law,
the filler was treated as elastic and the matrix as visco-hyperelastic. Material parameters were
determined experimentally for the binder and the cohesive parameters were obtained previously
from Williamson et al. (2014) and Gee et al. (2007) for the interface. Once calibrated, the material
laws were implemented in a finite element model to allow the macroscopic response of the
composite to be simulated. A finite element mesh was generated using a SEM image to identify
the filler particles which are represented as a set of 2D polygons. Simulated microstructures
were also generated with the same size distribution and volume fraction only with the idealised
assumption that the particles are a set of circles in 2D and spheres in 3D. The various model
results were compared and a number of other variables were examined for their influence on the
global deformation behaviour such as strain rate, cohesive parameters and contrast between filler
and matrix modulus. The overwhelming outcome is that the geometry of the particles plays a
crucial role in determining the onset of failure and the severity of fracture in relation to whether
it is a purely local or global failure. The model was validated against a set of uniaxial tensile
tests on PBX-1 and it was found that it predicted the initial modulus and failure stress and strain
well.
Keywords: Particulate composites, High volume fraction, Finite Element Analysis,
Micromechanics, Fracture, PBX and Viscoelastic matrix composite
Date Issued
2015-08-21
Date Acceptance
2015-08-01
Citation
Computational Materials Science, 2015, 110, pp.91-101
ISSN
0927-0256
Publisher
Elsevier
Start Page
91
End Page
101
Journal / Book Title
Computational Materials Science
Volume
110
Copyright Statement
© 2015, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Subjects
Particulate composites
High volume fraction
Finite element analysis
Micromechanics
Fracture
PBX and viscoelastic matrix composite
Publication Status
Published