2-Scale Hierarchical Multiscale Modeling of Piezoresistive Response in Polymer Nanocomposite Bonded Explosives

2015 ◽  
Author(s):  
Krishna K. Talamadupula ◽  
Adarsh K. Chaurasia ◽  
Gary D. Seidel
Keyword(s):  
Multiscale Modeling ◽  
Polymer Nanocomposite ◽  
Grain Structure ◽  
Current Work ◽  
Interfacial Damage ◽  
Polymer Medium ◽  
Hierarchical Framework ◽  
Key Features ◽  
Hierarchical Multiscale ◽  
Cohesive Zones

The current work aims to explore the effective piezoresistive response of polymer bonded explosive (PBX) materials where the polymer medium is reinforced with carbon nanotubes (CNTs). The effective piezoresistive response of these nanocomposite bound polymer explosives (NCBX) is evaluated using micromechanics based 2-scale hierarchical model connecting the CNT-polymer nanocomposite scale (nanoscale) to the explosive grain structure scale (microscale). The binding nanocomposite medium is modeled as electromechanical cohesive zones between adjacent explosive grains which are representative of effective electromechanical response of CNT-polymer nanocomposites. The hierarchical framework developed here is used to explore key features of the NCBX microstructure, e.g. ratio of grain to nanocomposite stiffness, ratio of grain to nanocomposite conductivities etc., and related to the NCBX effective piezoresistive response. The results obtained from the current work show dependence of effective NCBX piezoresistive properties on each of these microstructural features with and without interfacial damage between the explosive grains.

2-Scale Hierarchical Multiscale Modeling of Piezoresistive and Damage Response in Polymer Nanocomposite Bonded Explosive

2016 ◽  
Author(s):  
Krishna K. Talamadupula ◽  
Adarsh K. Chaurasia ◽  
Gary D. Seidel
Keyword(s):  
Polymer Nanocomposite ◽  
Grain Structure ◽  
Polymer Medium ◽  
Piezoresistive Effect ◽  
Weight Percentage ◽  
Hierarchical Framework ◽  
Damage Response ◽  
Work Done ◽  
Hierarchical Multiscale ◽  
Cohesive Zones

This paper builds on previous work done [1, 2] to explore the effective piezoresistive response of polymer bonded explosive (PBX) materials where the polymer medium is reinforced with carbon nanotubes (CNTs). In the present work, the nanocomposite binder is modeled explicitly as a piezoresistive material whose properties are determined from the nanoscale through a micromechanics based 2-scale hierarchical model connecting the nanoscale to the microscale grain structure. Electromechanical cohesive zones are used to model the interface between the grains and nanocomposite binder in order to characterize interface separation and the resulting piezoresistive effect. The overall microscale piezoresistive effect is measured by using the volume averaged properties of the microscale RVE. The hierarchical framework developed here is used to explore key features of the NCBX microstructure such as the effect of grain conductivity, weight percentage of CNTs used and nanocomposite gage factor.

Review of Hierarchical Multiscale Modeling to Describe the Mechanical Behavior of Amorphous Polymers

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
J. L. Bouvard ◽  
D. K. Ward ◽  
D. Hossain ◽  
S. Nouranian ◽  
E. B. Marin ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Multiscale Modeling ◽  
Coarse Graining ◽  
Amorphous Polymers ◽  
Multiscale Methods ◽  
Structure Property ◽  
Lightweight Materials ◽  
Structure Property Relationships ◽  
Modeling Strategy ◽  
Hierarchical Multiscale

Modern computational methods have proved invaluable for the design and analysis of structural components using lightweight materials. The challenge of optimizing lightweight materials in the design of industrial components relates to incorporating structure-property relationships within the computational strategy to incur robust designs. One effective methodology of incorporating structure-property relationships within a simulation-based design framework is to employ a hierarchical multiscale modeling strategy. This paper reviews techniques of multiscale modeling to predict the mechanical behavior of amorphous polymers. Hierarchical multiscale methods bridge nanoscale mechanisms to the macroscale/continuum by introducing a set of structure-property relationships. This review discusses the current state of the art and challenges for three distinct scales: quantum, atomistic/coarse graining, and continuum mechanics. For each scale, we review the modeling techniques and tools, as well as discuss important recent contributions. To help focus the review, we have mainly considered research devoted to amorphous polymers.

Multiscale Modeling of Large Deformation Processes in Polycrystalline Metals

2003 ◽  
Author(s):  
Antoinette Maniatty ◽  
Karel Matous ◽  
Jing Lu
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Grain Structure ◽  
Current Work ◽  
Integration Scheme ◽  
Two Dimensional ◽  
Scale Bridging ◽  
Grain Structures ◽  
Backward Euler ◽  
Bulk Response

A mesoscale model for predicting the evolution of the grain structure and the mechanical response of polycrystalline aggregates subject to large deformations, such as arise in bulk metal forming processes, is presented. The gain structures modeled are either experimentally observed or are computer generated and statistically similar to experimentally observed grain structures. In order to capture the inhomogeneous deformations and the resulting grain structure characteristics, a discretized model at the mesoscale is used. This work focuses on Al-Mg-Si alloys. Scale bridging is used to link to the macroscale. Examples involving two-dimensional grain structures and current work on three-dimensional grain structures are presented. The present work provides a framework to model the mesoscopic behavior and interactions between grains during finite strains. The mesoscale is characterized by a statistically representative voluem element (RVE), which contains the grains of a polycrystal. Experimentally observed grain structures are used both as models directly (for two-dimensional cases) and to define statistical characteristics to verify the similarity of computer generated grain structures (for three-dimensional cases). A Monte Carlo method based on the Potts model is used to define three-dimensional grain structures. In order to make the representative grain structure appropriate for scale-bridging, we design them with periodicity. A three-field, updated Lagrangian finite element formulation with a kinematic split of the deformation gradient into volume preserving and volumetric parts is used to create a stable finite element method in the context of nearly incompressible behavior. A fully implicit two-level backward Euler integration scheme is derived for integrating the constitutive equations, and consistent linearization is used in Newton’s method to solve the resulting equations. In addition, the average of the boundary conditions and bulk response must match the macroscopically measured bulk response. To illustrate and verify the proposed model, we analyze examples involving two-dimensional grain structures and compare with results from a Taylor model. Current work on three-dimensional grain structures ara also presented.

Hierarchical multiscale modeling of Polyvinyl Alcohol/Montmorillonite nanocomposites

Polymer ◽  
2016 ◽  
Vol 99 ◽  
pp. 386-398 ◽  
Author(s):  
W.B. Lawrimore ◽  
B. Paliwal ◽  
M.Q. Chandler ◽  
K.L. Johnson ◽  
M.F. Horstemeyer
Keyword(s):  
Polyvinyl Alcohol ◽  
Multiscale Modeling ◽  
Hierarchical Multiscale ◽  
Montmorillonite Nanocomposites

A PERIDYNAMICS FORMULATION BASED HIERARCHICAL MULTISCALE MODELING APPROACH BETWEEN CONTINUUM SCALE AND ATOMISTIC SCALE

2012 ◽  
Vol 01 (03) ◽  
pp. 1250029 ◽  
Author(s):  
R. RAHMAN ◽  
A. HAQUE
Keyword(s):  
Multiscale Modeling ◽  
Continuum Model ◽  
Molecular Model ◽  
Multiscale Simulation ◽  
Coupling Method ◽  
Fine Scale ◽  
Modeling Framework ◽  
Multiscale Modeling Framework ◽  
Hierarchical Multiscale ◽  
Nonlocal Force

In this paper, a multiscale modeling framework has been established between peridynamics and atomistic models. Peridynamics (PD) formulation is based on continuum theory implying nonlocal force based interactions. Peridynamics (PD) and molecular dynamics (MD) have similarities since both use nonlocal force based interaction. It means continuum points in PD and MD atoms are separated by finite distance and exert force upon each other. In this work PD based continuum model of epoxy polymer is defined by meshless Lagrangian particles. MD is coupled with PD based continuum model through a hierarchical multiscale modeling framework. In this framework, PD particles at coarse scale interact with fine scale PD particles by transferring pressure, displacements and velocities among each other. Based on the same hierarchical coupling method, fine scale PD model is seamlessly interfaced with molecular model through an intermediate mesoscale region i.e. coarse-grain atomic model. At the end of this hierarchical downscaling, the information — such as deformation, energy and other important parameters — were captured in the atomistic region under the applied force at micro and macro regions. A two-dimensional plate of neat epoxy was considered for demonstration of such multiscale simulation platform. The region of interest in the 2D plate was interfaced with atomistic model by applying the proposed hierarchical coupling method. The results show reasonable consistency between PD and MD simulations.

Hierarchical Multiscale Modeling of Methane Steam Reforming Reactions

2011 ◽  
Vol 50 (5) ◽  
pp. 2600-2612 ◽  
Author(s):  
De Chen ◽  
Rune Lødeng ◽  
Hallvard Svendsen ◽  
Anders Holmen
Keyword(s):  
Multiscale Modeling ◽  
Steam Reforming ◽  
Methane Steam Reforming ◽  
Methane Steam ◽  
Hierarchical Multiscale ◽  
Reforming Reactions
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