OOF2: The Manual
The physical characteristics of an OOF2 Microstructure
are contained
in one or more Material
objects. Materials are created by
assembling lists of Property
objects, and are assigned to
Microstructure
pixels in the Materials Page.
Properties come in a variety of categories. Most, such as
Elasticity
or ThermalExpansion
represents terms in constitutive equations. Others, such as
Orientation
,
modify those terms, and at least one, Color
,
serves only a decorative function.
All of the Properties
predefined in OOF2 are listed by
category in Section 6.4.1 in Chapter 6. Chapter 7 explains how to add new
Properties
.
Many Properties
have subcategories. For example, Elasticity
is divided into Isotropic
and Anisotropic
,
and Anisotropic
is further divided into
Cubic
and all the other crystal symmetries. Generally, a Material
may contain only one Property
from each category. Some
categories of Properties
make sense only if a property of
another category is defined in the same Material
-- for
example, it's an error to include a
Cubic
elasticity without also including
an Orientation
. OOF2 will notify you
of badly formed Materials
when you solve a Mesh
.
When OOF2 starts, it creates a single
unnamed instance of each type of
Property
. New instances may be created by copying a
Property
and giving it a name. Both named and unnamed
Properties
may be used in Materials
. The commands in the
OOF.Property.Parametrize menu set
the parameters (e.g, Young's
modulus, conductivity, or color) for Properties
. Parameters
may be set in either named or unnamed Properties
.
Properties
are arranged in a hierarchical tree structure,
which is shown in the Property pane of
the Materials
task page. The “path” to a Property
is a colon
separated list of the names of the levels of the tree leading
to the Property
. For example, the path to cubic elasiticity
is
'Mechanical:Elasticity:Anisotropic:Cubic'
.
The path to a named property is created
by appending the name to the path to its unnamed version:
'Mechanical:Elasticity:Anisotropic:Cubic:salt'
is
a cubic elasticity Property
named “salt”. Most
commands that work on Properties
in scripts refer to them by
their paths. The exceptions are the OOF.Property.Parametrize and OOF.LoadData.Property menus, which
instead embed the Property
name in the name of the command.
That is, the command to parametrize a cubic elastic property
is OOF.Property.Parametrize.Mechanical.Elasticity.Anisotropic.Cubic,
and the command to parametrize a cubic elastic property named
“salt” is
OOF.Property.Parametrize.Mechanical.Elasticity.Anisotropic.Cubic.salt.
(Fortunately, the user rarely has to type these names in
full.) The arguments for the named and unnamed forms are the
same, and are listed in the documentation under OOF.Property.Parametrize.
Many Properties
are anisotropic: their values depend on the
orientation of the crystalline axes. In OOF2, although the
calculations are two dimensional, crystalline orientations are
full three dimensional rotations. They can be specified in a
number of ways as subclasses of the Orientation class.
Any Material
that contains an anisotropic Property
must
also contain either an Orientation
Property
or an OrientationMap
Property
. The difference betweeen them is that an Orientation
Property
has an argument which specifies the orientation,
whereas an OrientationMap
Property
gets the orientation from the Microstructure
's Orientation
Map
. The existence of the Orientation
Map
in a Microstructure
does not automatically
imply that the Microstructure
's Materials
will derive their
orientations from it. The OrientationMap
Property
must also be present. This allows some Materials
to get their orientations from the map while others do not.