ABAQUS Volume II: I–Z User Manual

Page 423

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*SHELL SECTION

In ABAQUS/Standard the default is POISSON=0.5; in ABAQUS/Explicit the default is

POISSON=MATERIAL.

STACK DIRECTION

This parameter is relevant only for continuum shells.

This parameter defines the continuum shell stack or thickness direction. Set this parameter

equal to 1, 2, 3, or ORIENTATION. The default is STACK DIRECTION=3. The ORIENTATION
parameter must also be used if STACK DIRECTION=ORIENTATION.

SECTION INTEGRATION

Set SECTION INTEGRATION=SIMPSON (default) to use Simpson’s rule for the shell section
integration.

Set SECTION INTEGRATION=GAUSS to use Gauss quadrature for the shell section

integration. Gauss quadrature cannot be used for heat transfer or thermally coupled shell elements.

TEMPERATURE

Use this parameter to select the mode of temperature and field variable input used on the *FIELD,
the *INITIAL CONDITIONS, or the *TEMPERATURE options.

Omit the TEMPERATURE parameter to define the predefined field by its magnitude on the

reference surface of the shell and its gradient through the thickness.

Set TEMPERATURE=n, where n is the number of predefined field variable points in the shell

or in each layer if the COMPOSITE parameter is used, to define the predefined field at n equally
spaced points through each layer of the shell section.

In a heat transfer analysis step or a coupled temperature-displacement analysis step when

the *FIELD option is used to specify values of predefined field variables, the TEMPERATURE
parameter is required to specify the number of field variable points in the shell. The number of
temperature points in the shell with temperature degrees of freedom is defined by the number of
integration points specified on the data lines.

THICKNESS MODULUS

This parameter is relevant only for continuum shells.

Set this parameter equal to an effective thickness modulus. The default effective thickness

modulus is twice the initial in-plane shear modulus based on the material definition.

Data line to define a homogeneous shell (the MATERIAL parameter is included):

First (and only) line:

1. Shell thickness. This value is ignored if the NODAL THICKNESS parameter is included.

2. Number of integration points to be used through the shell section. The default is five points if

Simpson’s rule is used and three points if Gauss quadrature is used. The number of integration
points must be an odd number for Simpson’s rule and, in an ABAQUS/Standard analysis, is
equal to the number of temperature degrees of freedom at a node of the element if this section
is associated with heat transfer or coupled temperature-displacement elements. This number
must be at least 2 and less than or equal to 7 for Gauss quadrature. For Simpson’s rule it must

18.15–3

ABAQUS Version 6.1

Module: ID:

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