Research Website

www.nanoHUB.org

Keywords

granular matter, Heterogeneous composites, nanotechnology, consolidation, perturbation

Presentation Type

Event

Research Abstract

Heterogeneous (nano) composites, manufactured by the densification of variously sized grains, represent an important and ubiquitous class of technologically relevant materials. Typical grain sizes in such materials range from macroscopic to a few nanometers. The morphology exhibited by such disordered materials is complex and intricately connected with its thermal and electrical transport properties. It is important to quantify the geometric features of these materials and simulate the fabrication process. Additionally, granular materials exhibit complex structural and mechanical properties that crucially govern their reliability during industrial use. In this work, we simulate the densification of soft deformable grains from a low-density fluid-state to a mechanically rigid solid-state. The simulation is performed via methods of structural optimization that minimize the system free energy in the athermal limit. The effect of grain shapes and sizes (and dispersity therein) is simulated in detail and their effect on the composite morphology is quantified. Furthermore, in the present simulations the composite materials are perturbed under external stress (strain) stimuli to understand the mechanical response and calculate the material stress-strain response, effective Poisson’s ratio and yield stress. A tool is created to simulate the consolidation and stress-perturbation of the different shaped and sized grains using techniques of computational geometry and gradient-based optimization routines to relax microstructures into minimum-energy stable phases. The tool uses MATLAB and C++, wrapped around xml for generating Graphical User Interface (GUI). The tool can be deployed online in nanoHUB platform of Network for Computational Nanotechnology (NCN). Besides computing the data like enthalpy of the system and internal stress, this tool also utilizes visualization technique like Visualization ToolKit (VTK) to graph and visualize the optimized microstructures. Hence, the creation of this tool allows the wider audiences simulate the consolidation and stress-perturbation of the different shaped and sized grains.

Session Track

Simulation

Share

COinS
 
Aug 7th, 12:00 AM

Granular Matter: Microstructural Evolution and Mechanical Response

Heterogeneous (nano) composites, manufactured by the densification of variously sized grains, represent an important and ubiquitous class of technologically relevant materials. Typical grain sizes in such materials range from macroscopic to a few nanometers. The morphology exhibited by such disordered materials is complex and intricately connected with its thermal and electrical transport properties. It is important to quantify the geometric features of these materials and simulate the fabrication process. Additionally, granular materials exhibit complex structural and mechanical properties that crucially govern their reliability during industrial use. In this work, we simulate the densification of soft deformable grains from a low-density fluid-state to a mechanically rigid solid-state. The simulation is performed via methods of structural optimization that minimize the system free energy in the athermal limit. The effect of grain shapes and sizes (and dispersity therein) is simulated in detail and their effect on the composite morphology is quantified. Furthermore, in the present simulations the composite materials are perturbed under external stress (strain) stimuli to understand the mechanical response and calculate the material stress-strain response, effective Poisson’s ratio and yield stress. A tool is created to simulate the consolidation and stress-perturbation of the different shaped and sized grains using techniques of computational geometry and gradient-based optimization routines to relax microstructures into minimum-energy stable phases. The tool uses MATLAB and C++, wrapped around xml for generating Graphical User Interface (GUI). The tool can be deployed online in nanoHUB platform of Network for Computational Nanotechnology (NCN). Besides computing the data like enthalpy of the system and internal stress, this tool also utilizes visualization technique like Visualization ToolKit (VTK) to graph and visualize the optimized microstructures. Hence, the creation of this tool allows the wider audiences simulate the consolidation and stress-perturbation of the different shaped and sized grains.

http://docs.lib.purdue.edu/surf/2014/presentations/64