Specifying advanced properties for composite shell
sections
You can specify advanced properties for composite
shell sections.
Context:
On the Advanced tabbed page:
Specify the Shell thickness.
Choose Use section thickness to use the
thickness calculated from the individual layer thicknesses.
Choose Element distribution; and select
either an analytical field, labeled with an (A), or an element-based discrete
field, labeled with a (D), to define a spatially varying element-based shell
thickness. Alternatively, you can click
to create a new analytical field or click
to create a new discrete field. See
The Analytical Field toolset
and
The Discrete Field toolset
for more information.
Choose Nodal distribution; and select either
an analytical field, labeled with an (A), or a node-based discrete field,
labeled with a (D), to define a spatially varying node-based shell thickness.
Alternatively, you can click
to create a new analytical field or click
to create a new discrete field. See
The Analytical Field toolset
and
The Discrete Field toolset
for more information.
Specify the Section Poisson's ratio to define the
shell thickness behavior.
In conventional shell elements that permit finite membrane strains
in large-deformation analysis, specifying the section Poisson's ratio causes
the shell thickness to change as a function of membrane strains:
Toggle on Use analysis default to use the
default value. In
Abaqus/Standard
the default value is 0.5, which will enforce incompressible behavior of the
element for membrane strains. In
Abaqus/Explicit
the default is to base the change in thickness on the element material
definition.
Toggle on Specify value, and enter a
value for the Poisson's ratio. This value must be between −1.0 and 0.5. A value
of 0.0 will enforce constant shell thickness, and a negative value will result
in an increase in the shell thickness in response to tensile membrane strains.
In continuum shell elements specifying the section Poisson's ratio
defines the thickness behavior for both small- and large-displacement analysis:
Toggle on Use analysis default to
indicate that the change in thickness is based on the element material
definition.
Toggle on Specify value, and enter a
value for the Poisson's ratio to cause the shell thickness to change as a
function of membrane strains. This value must be between −1.0 and 0.5. A value
of 0.5 cannot be used with continuum shells. A value of 0.0 will enforce
constant shell thickness, and a negative value will result in an increase in
the shell thickness in response to tensile membrane strains.
For continuum shell elements, toggle on Thickness
modulus, and enter a value for the effective thickness modulus. If
you do not specify a thickness modulus,
Abaqus
will try to compute it based on the initial elastic material properties.
If you are specifying properties for composite shell sections
integrated during the analysis, select a method for defining the
Temperature variation through the section:
Choose Linear through thickness to indicate
that the temperature at the reference surface and the temperature gradient or
gradients through the section are specified. You can use the
Load module
to specify these temperatures.
Choose Piecewise linear over
n values to enter the number of
temperature points (values) through the section in the text field provided. You
can use the
Load module
to specify the temperature at each of these points.
Toggle on Density, and enter a value for the mass
per unit surface area of the shell. The mass of the shell includes a
contribution from the density in addition to any contribution from the selected
material.
For most shell sections
Abaqus
will calculate the transverse shear stiffness values required in the element
formulation. If desired, toggle on Specify values from the
Transverse Shear Stiffnesses options to include nondefault
transverse shear stiffness effects in the section definition, and enter values
for ,
the shear stiffness of the section in the first direction;
,
the coupling term in the shear stiffness of the section; and
,
the shear stiffness of the section in the second direction. If either value
or
is omitted or given as zero, the nonzero value will be used for both.