1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
|
#############################################################
## ##
## Copyright (c) 2003-2011 by The University of Queensland ##
## Earth Systems Science Computational Centre (ESSCC) ##
## http://www.uq.edu.au/esscc ##
## ##
## Primary Business: Brisbane, Queensland, Australia ##
## Licensed under the Open Software License version 3.0 ##
## http://www.opensource.org/licenses/osl-3.0.php ##
## ##
#############################################################
__docformat__ = "restructuredtext en"
import esys.lsm.doc.Util
import esys.lsm.util.InstallInfo
__esysParticleOverviewSection = \
"""
%(pkgName)s Overview
==================================
The Lattice Solid Model (LSM) [MoraPAGEOPH1994]_, [PlaceJCompPhys1999]_ is a particle-based
model similar to the Distinct Element Model [CundallGeotech1979]_.
The model consists of particles which are characterized by
their shape, mass, position, orientation and velocity. The particles
interact with their nearest neighbours by imparting contact forces.
Typically, Discrete Element Model (DEM) particles are spherical and the
contact forces consist of a linear elastic normal component and linear
elastic tangential component. %(pkgName)s is a parallel implementation
of the LSM with a Python_ scripting interface.
.. _Python: http://www.python.org
Particle Types
--------------
Currently, there exist three types of %(pkgName)s spherical particles:
*non-rotational*, *rotational*, *thermal-rotational*:
Non-rotational Spheres
Non-rotational spherical particles possess no rotational
degrees of freedom. Objects of class `esys.lsm.NRotSphere`
represent non-rotational spherical particles.
Rotational Spheres
Rotational spherical particles possess orientation information.
Particles of this type change orientation according to the
applied moments. Objects of class `esys.lsm.RotSphere`
represent rotational spherical particles.
Thermal Rotational Spheres
Thermal rotational spherical particles are the same as "Rotational Spheres"
with the addition of thermal properties (temperature and thermal expansion).
Objects of class `esys.lsm.RotThermalSphere`
represent thermal rotational spherical particles.
Inter-particle Interactions
---------------------------
Interactions between model particles are also classified as
*non-rotational* and *rotational*. Two spherical particles
involved in a non-rotational interaction have
all forces applied at the centre of mass.
Two spherical particles involved in a
rotational interaction experience moments
due to forces which are, typically, applied
at a *contact point*. The inter-particle interactions
include:
Non-rotational Elastic
Purely linear elastic repulsion of particles when in contact.
Non-rotational Bonded
Linear elastic attraction and repulsion while bond remains intact.
Bond *breaks* when a threshold separation distance is reached.
Non-rotational Friction
Linear elastic repulsion, linear elastic shear rigidity and Coulomb
dynamic friction law.
Rotational Elastic
Linear elastic repulsion as well as linear elastic shear rigidity.
Rotational Bonded
Linear elastic tension, compression, shear, torsion and bending
forces while bond remains intact. Bond *breaks* if a threshold
force limit is reached.
Rotational Friction
Linear elastic repulsion, linear elastic shear rigidity and Coulomb
dynamic friction law.
Thermal Non-rotational Elastic
Linear elastic repulsion as well as heat transfer.
Thermal Rotational Bonded
Same as "Rotational Bonded" with addition of heat transfer.
Thermal Rotational Friction
Same as "Rotational Friction" with addition of heat transfer and
heat generation during frictional slip.
Fixed objects
-------------
Particles not only interact with other particles, but also with
*fixed* objects within the model. These fixed objects are not
subject to the laws of motion and provide a means of imposing
particular types of boundary conditions. Fixed objects include:
Walls
An infinite plane characterized by position and normal direction.
Linear Mesh
A piecewise linear mesh which can be used to represent a surface in 2D.
Triangular mesh
A triangular mesh which can be used to represent a surface in 3D.
"""
__citSection = \
"""
References
==========
.. [CundallGeotech1979] P.A. Cundall and O.A.D Strack
(1979)
"A Discrete Numerical Model for Granular Assemblies",
*Ge\'otechnique*,
**vol. 29**,
pp. 47-65.
.. [MoraPAGEOPH1994] P. Mora and D. Place
(1994)
"Simulation of the Stick-Slip Instability",
*Pure Appl. Geophys.*,
**vol. 143**,
pp. 61-87.
.. [PlaceJCompPhys1999] D. Place and P. Mora
(1999)
"The Lattice Solid Model to Simulate the Physics of Rocks and Earthquakes:
Incorporation of Friction",
*J. Comp. Physics*,
**vol. 150**,
pp. 332-372.
"""
__doc__ = \
esys.lsm.doc.Util.setSectionDoc("ESySParticleOverviewSection",__esysParticleOverviewSection) \
+ esys.lsm.doc.Util.setSectionDoc("CitationSection",__citSection) \
+ ("\n:summary: %s overview.\n" % esys.lsm.util.InstallInfo.pkgName)
|
