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Implementation and Validation of an Anisotropic Influence Function in PDLAMMPS

Krochmal, Jakob LU (2017) FME820 20162
Mechanics
Abstract
Technological advancements into the nanoscale have made it necessary to perform
solid mechanical calculations on devices being produced on this scale. Traditionally, the field of continuum mechanics has been used to perform calculations in the field of solid mechanics, but the ubiquity of faster computers have opened up the field of peridynamics as an alternative. Peridynamic theory models materials on a per-particle basis, making it an attractive alternative when it comes to the nanoscale where objects are often only a few thousand atoms in volume. Furthermore, peridynamics can handle discontinuities which classical continuum mechanics cannot. To perform these calculations, the department of mechanics at the engineering faculty of Lund... (More)
Technological advancements into the nanoscale have made it necessary to perform
solid mechanical calculations on devices being produced on this scale. Traditionally, the field of continuum mechanics has been used to perform calculations in the field of solid mechanics, but the ubiquity of faster computers have opened up the field of peridynamics as an alternative. Peridynamic theory models materials on a per-particle basis, making it an attractive alternative when it comes to the nanoscale where objects are often only a few thousand atoms in volume. Furthermore, peridynamics can handle discontinuities which classical continuum mechanics cannot. To perform these calculations, the department of mechanics at the engineering faculty of Lund University uses a software called LAMMPS - Large-scale Atomic/Molecular
Massively Parallel Simulator, developed at Sandia laboratory in the United States.
LAMMPS performs peridynamic simulations but can by default only perform simulations on materials that are expected to deform uniformly regardless of the direction of the forces the material is being subjected to, known as isotropic materials. Unfortunately, many materials are instead anisotropic - they do not behave uniformly when subjected to forces or stresses in different directions.
In this thesis, a mathematical model is implemented into LAMMPS and tested as
a proof of concept for a method of simulating anisotropic materials. The model is
introduced into source files of LAMMPS itself, extending the program in a straightforward manner. The implemented model is tested through simulating nano-beams in LAMMPS with and without the model. The model is found to severely alter the behaviour of the simulations. Clear qualitative dierences in behaviour is shown independently of pre-existing simulation parameters. The model is shown to be internally consistent. (Less)
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Normally well-behaved materials work differently when very small things are simulated. My master thesis developed and tested a model for how to better simulate crushing of very small things.
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author
Krochmal, Jakob LU
supervisor
organization
course
FME820 20162
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
8898542
date added to LUP
2017-01-17 09:50:37
date last changed
2017-05-22 11:26:46
@misc{8898542,
  abstract     = {{Technological advancements into the nanoscale have made it necessary to perform
solid mechanical calculations on devices being produced on this scale. Traditionally, the field of continuum mechanics has been used to perform calculations in the field of solid mechanics, but the ubiquity of faster computers have opened up the field of peridynamics as an alternative. Peridynamic theory models materials on a per-particle basis, making it an attractive alternative when it comes to the nanoscale where objects are often only a few thousand atoms in volume. Furthermore, peridynamics can handle discontinuities which classical continuum mechanics cannot. To perform these calculations, the department of mechanics at the engineering faculty of Lund University uses a software called LAMMPS - Large-scale Atomic/Molecular
Massively Parallel Simulator, developed at Sandia laboratory in the United States.
LAMMPS performs peridynamic simulations but can by default only perform simulations on materials that are expected to deform uniformly regardless of the direction of the forces the material is being subjected to, known as isotropic materials. Unfortunately, many materials are instead anisotropic - they do not behave uniformly when subjected to forces or stresses in different directions.
In this thesis, a mathematical model is implemented into LAMMPS and tested as
a proof of concept for a method of simulating anisotropic materials. The model is
introduced into source files of LAMMPS itself, extending the program in a straightforward manner. The implemented model is tested through simulating nano-beams in LAMMPS with and without the model. The model is found to severely alter the behaviour of the simulations. Clear qualitative dierences in behaviour is shown independently of pre-existing simulation parameters. The model is shown to be internally consistent.}},
  author       = {{Krochmal, Jakob}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Implementation and Validation of an Anisotropic Influence Function in PDLAMMPS}},
  year         = {{2017}},
}