*SURFACE

Keyword type: model definition

This option is used to define surfaces made up of nodes or surfaces made up of element faces. A mixture of nodes and element faces belonging to one and the same surface is not possible. There are two parameters: NAME and TYPE. The parameter NAME containing the name of the surface is required. If the name of an already existing surface is used, the latter is extended by the nodes or faces listed underneath the *SURFACE keyword. The TYPE parameter takes the value NODE for nodal surfaces and ELEMENT for element face surfaces. Default is TYPE=ELEMENT. At present, surfaces are used e.g. to establish cyclic symmetry conditions or to define contact (including tied contact).

Element faces are identified by the surface label Sx where x is the number of the face. The numbering depends on the element type.

For hexahedral elements the faces are numbered as follows (numbers are node numbers):

• Face 1: 1-2-3-4
• Face 2: 5-8-7-6
• Face 3: 1-5-6-2
• Face 4: 2-6-7-3
• Face 5: 3-7-8-4
• Face 6: 4-8-5-1

for tetrahedral elements:

• Face 1: 1-2-3
• Face 2: 1-4-2
• Face 3: 2-4-3
• Face 4: 3-4-1

and for wedge elements:

• Face 1: 1-2-3
• Face 2: 4-5-6
• Face 3: 1-2-5-4
• Face 4: 2-3-6-5
• Face 5: 3-1-4-6

for quadrilateral plane stress, plane strain and axisymmetric elements:

• Face 1: 1-2
• Face 2: 2-3
• Face 3: 3-4
• Face 4: 4-1
• Face N: in negative normal direction (only for plane stress)
• Face P: in positive normal direction (only for plane stress)

for triangular plane stress, plane strain and axisymmetric elements:

• Face 1: 1-2
• Face 2: 2-3
• Face 3: 3-1
• Face N: in negative normal direction (only for plane stress)
• Face P: in positive normal direction (only for plane stress)

for quadrilateral shell elements:

• Face NEG or 1: in negative normal direction
• Face POS or 2: in positive normal direction
• Face 3: 1-2
• Face 4: 2-3
• Face 5: 3-4
• Face 6: 4-1

for triangular shell elements:

• Face NEG or 1: in negative normal direction
• Face POS or 2: in positive normal direction
• Face 3: 1-2
• Face 4: 2-3
• Face 5: 3-1

Notice that the labels 1 and 2 correspond to the brick face labels of the 3D expansion of the shell (Figure 69).

for beam elements:

• Face 1: in negative 1-direction
• Face 2: in positive 1-direction
• Face 3: in positive 2-direction
• Face 5: in negative 2-direction

The beam face numbers correspond to the brick face labels of the 3D expansion of the beam (Figure 74).

First line:

• *SURFACE
• Enter the parameter NAME and its value, and, if necessary, the TYPE parameter.

Following line for nodal surfaces:

• Node or node set to be assigned to this surface (maximum 1 entry per line).

Repeat this line if needed.

Following line for element face surfaces:

• Element or element set (maximum 1 entry per line).
• Surface label (maximum 1 entry per line).

Repeat this line if needed.

Example:

*SURFACE,NAME=left,TYPE=NODE
part,
1,
8

assigns the nodes with number 1, and 8 and the nodes belonging to node set part to a surface with name left.

Example:

*SURFACE,NAME=new
38,S6

assigns the face 6 of element 38 to a surface with name new.

Example files: segment, fullseg.