*SHELL SECTION

Keyword type: model definition

This option is used to assign material properties to shell element sets. The parameter ELSET is required, one of the mutually exclusive parameters MATERIAL and COMPOSITE is required too, whereas the parameters ORIENTATION, NODAL THICKNESS, OFFSET are optional. The parameter ELSET defines the shell element set to which the material specified by the parameter MATERIAL applies. The parameter ORIENTATION allows to assign local axes to the element set. If activated, the material properties are applied to the local axis. This is only relevant for non isotropic material behavior. The parameter NODAL THICKNESS indicates that the thickness for ALL nodes in the element set are defined with an extra *NODAL THICKNESS card and that any thicknesses defined on the *SHELL SECTION card are irrelevant. The OFFSET parameter indicates where the mid-surface of the shell should be in relation to the reference surface defined by the surface representation given by the user. The unit of the offset is the thickness of the shell. Thus, OFFSET=0 means that the reference surface is the mid-surface of the shell, OFFSET=0.5 means that the reference surface is the top surface of the shell. The offset can take any real value. Finally, the COMPOSITE parameter is used to define a composite material. It can only be used for S8R and S6 elements. A composite material consists of an integer number of layers made up of different materials with possibly different orientations. For a composite material the material is specified on the lines beneath the *SHELL SECTION card for each layer separately. The orientation for each layer can be defined in the same way. If none is specified, the orientation defined by the ORIENTATION parameter will be taken, if any.

For structures in which axisymmetric elements (type CAX*) are present any thickness defined on the present card applies to 360^\circ.

First line:

• *SHELL SECTION
• Enter any needed parameters.

Second line if the parameter COMPOSITE is not used (only read if the first line does not contain NODAL THICKNESS):

• thickness

Second line if the parameter COMPOSITE is used (NODAL THICKNESS is not allowed):

• thickness (required)
• not used
• name of the material to be used for this layer (required)
• name of the orientation to be used for this layer (optional)

Repeat this line as often as needed to define all layers.

Example:

*SHELL SECTION,MATERIAL=EL,ELSET=Eall,ORIENTATION=OR1,OFFSET=-0.5
3.

assigns material EL with orientation OR1 to all elements in (element) set Eall. The reference surface is the bottom surface of the shell and the shell thickness is 3 length units.

Example files: shell1, shell2, shellbeam.