Computational modeling of advanced, multi-material energetic materials and systems

Hernandez, Alberto M.

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https://hdl.handle.net/2142/102411 Copy

Description

Title

Computational modeling of advanced, multi-material energetic materials and systems

Author(s)

Hernandez, Alberto M.

Issue Date

2018-10-19

Director of Research (if dissertation) or Advisor (if thesis)

Stewart, Donald S.

Doctoral Committee Chair(s)

Stewart, Donald S.

Committee Member(s)

• Matalon, Moshe
• Glumac, Nick
• Fischer, Paul

Department of Study

Mechanical Sci & Engineering

Discipline

Theoretical & Applied Mechanics

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(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.

Graduation Semester

2018-12

Type of Resource

text

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http://hdl.handle.net/2142/102411

Copyright and License Information

Copyright 2018 Alberto M. Hernández. All rights reserved.

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