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Title:Computational modeling of advanced, multi-material energetic materials and systems
Author(s):Hernandez, Alberto M.
Director of Research:Stewart, Donald S.
Doctoral Committee Chair(s):Stewart, Donald S.
Doctoral Committee Member(s):Matalon, Moshe; Glumac, Nick; Fischer, Paul
Department / Program:Mechanical Sci & Engineering
Discipline:Theoretical & Applied Mechanics
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Multi-material
reactive flow
parallel computing
level sets
compressible Euler equations
solid internal boundaries
node sorting
computational physics
Abstract:The aim of this thesis is to develop and implement a robust reactive simulation tool that can aid in the design of explosive devices by numerically investigating the reactive mechanism of different explosive materials; study how detonation waves travel through them and determine how to initiate explosives with the smallest amount of booster material. These types of problems are numerically challenging to model and require multiple components that interact with each other. Multi-material models are necessary since shocks and detonation waves will travel through and impinge on material interfaces. High order and robust methods are needed to maintain sharp representations of these material boundaries. They need to be capable of numerically maintaining stable interfaces between high energy explosive materials and low density inerts such as air. This is a challenging problem since it involves strong wave interactions at the interface, large pressure and density gradients across the same, and non-linearity issues that result from the use of real equations of state. From a software developing point of view, consistent code infrastructure also needs to be followed to allow the ability to easily implement new models and modify existing ones. Also, given the multi-scaled nature of these types of problems, methods need to be efficient and scalable in both shared and distributed memory architectures for parallel computing. The proposed parallel and robust numerical reactive hydrodynamic solver implementation maintains sharp solid and material interfaces. The solver is designed to run on distributed memory architectures using a simple yet efficient MPI communication implementation. Multiple level sets are used to track the evolution of material interfaces over time and represent internal solid regions. Approximate Riemann solvers and the Ghost Fluid Method or Overlap Domain Method are used to enforce appropriate interface boundary conditions. Ghost nodes are set by a new local and point-wise node sorting algorithm that decouples these nodes by establishing their connectivity to other ghost nodes. This approach allows us to enforce boundary conditions via a direct procedure removing the need to solve a coupled system of equations numerically. Issues concerning the use of reactive, non-ideal equations of state and their implementation in high explosive hydrodynamic codes are studied. The accuracy and fidelity of the solver is examined by simulating a series of explosive multi-material problems, showing good agreement between numerical results and experimental data.
Issue Date:2018-10-19
Type:Text
URI:http://hdl.handle.net/2142/102411
Rights Information:Copyright 2018 Alberto M. Hernández. All rights reserved.
Date Available in IDEALS:2019-02-06
Date Deposited:2018-12


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