ABAQUS Keywords Reference Manual  


15. O

*ORIENTATION
Define a local axis system for material or element property definition, for kinematic coupling constraints, for free directions for inertia relief loads, or for connectors.

This option is used to define a local coordinate system for definition of material properties; for material calculations at integration points; for element property definitions (e.g., connector elements); for output of components of stress, strain, and element section forces; and for kinematic and distributing coupling constraints. In ABAQUS/Standard it can be used to define local directions for contact pair interaction properties and spring, dashpot, and JOINTC elements; for definition of local free directions for inertia relief loads; and for output of components of surface variables.

Products: ABAQUS/Standard  ABAQUS/Explicit  

Type: Model data

Level: Part  Part Instance  Assembly  

References:

Required parameter:

NAME

Set this parameter equal to the name to be used to identify the orientation definition. Orientation names in the same input file must be unique.

Optional parameters:

DEFINITION

Set DEFINITION=COORDINATES (default) to define the local system by giving the coordinates of the three points , , and, optionally, (the origin) appropriate to the SYSTEM choice from Figure 15.1–1.

Set DEFINITION=NODES to define the local system by giving global node numbers for points , , and, optionally, (the origin).

Set DEFINITION=OFFSET TO NODES to define the local system by giving local node numbers (on the element where the orientation is being used) to define the points , , and, optionally, (the origin) in Figure 15.1–1. This parameter value cannot be used with spring, dashpot, or JOINTC elements. In addition, it cannot be used with the *KINEMATIC COUPLING, *INERTIA RELIEF, or *CONTACT PAIR options.

SYSTEM

Set SYSTEM=RECTANGULAR (default) to define a rectangular Cartesian system by the three points , , and  shown in Figure 15.1–1. Point is the origin of the system, point must lie on the -axis, and point must lie on the - plane. Although not necessary, it is intuitive to select point such that it is on or near the local -axis.

Set SYSTEM=CYLINDRICAL to define a cylindrical system by giving the two points  and  on the polar axis of the cylindrical system (Figure 15.1–1). The local axes are 1=radial, 2=circumferential, 3=axial.

Set SYSTEM=SPHERICAL to define a spherical system by giving the center of the sphere, , and point on the polar axis (Figure 15.1–1). The local axes are 1=radial, 2=circumferential, 3=meridional.

Set SYSTEM=Z RECTANGULAR in an ABAQUS/Standard analysis to define a rectangular Cartesian system by the three points , , and  shown in Figure 15.1–1. Point is the origin of the system, point must lie on the -axis, and point must lie on the - plane. Although not necessary, it is intuitive to select point such that it is on or near the local -axis.

Set SYSTEM=USER in an ABAQUS/Standard analysis to define the local coordinate system in user subroutine ORIENT. The DEFINITION parameter and any data lines associated with the option are ignored if SYSTEM=USER.

Data lines to define an orientation using DEFINITION=COORDINATES: 

First line:

  1. -coordinate of point .

  2. -coordinate of point .

  3. -coordinate of point .

  4. -coordinate of point .

  5. -coordinate of point .

  6. -coordinate of point .

    7. The following items, the coordinates of point (the origin), are optional and relevant only for SYSTEM=RECTANGULAR and SYSTEM=Z RECTANGULAR. The default location of the origin, , is the global origin.

  7. -coordinate of point .

  8. -coordinate of point .

  9. -coordinate of point .

Second line (mandatory for shells, membranes, gaskets, composite solid sections, and contact pairs):

  1. Local direction about which the additional rotation is given. The default is the local 1-direction. For shell and membrane elements this direction should have a nonzero component in the direction of the normal to the surface.

  2. Additional rotation , in degrees. The default is zero degrees.

Data lines to define an orientation using DEFINITION=NODES: 

First line:

  1. Node number of the node at point .

  2. Node number of the node at point .

    3. The next item, specification of point (the origin), is optional and relevant only for SYSTEM=RECTANGULAR and SYSTEM=Z RECTANGULAR. The default location of the origin, , is the global origin.

  3. Node number of the node at point .

Second line (mandatory for shells, membranes, gaskets, composite solid sections, and contact pairs):

  1. Local direction about which the additional rotation is given. The default is the local 1-direction. For shell and membrane elements this direction should have a nonzero component in the direction of the normal to the surface.

  2. Additional rotation , in degrees. The default is zero degrees.

Data lines to define an orientation using DEFINITION=OFFSET TO NODES: 

First line:

  1. Local node number of point .

  2. Local node number of point .

    3. The next item, specification of point (the origin), is optional and relevant only for SYSTEM=RECTANGULAR and SYSTEM=Z RECTANGULAR. The default location of the origin, , is the first node of the element (local node number 1).

  3. Local node number of point .

Second line (mandatory for shells, membranes, gaskets, and composite solid sections):

  1. Local direction about which the additional rotation is given. The default direction for additional rotation is the local 1-direction. For shell and membrane elements this direction should have a nonzero component in the direction of the normal to the surface.

  2. Additional rotation , in degrees. The default is zero degrees.

To define an orientation using a user subroutine (SYSTEM=USER): 

No data lines are used with this option when SYSTEM=USER is specified. Instead, user subroutine ORIENT must be used to define the orientation (“ORIENT,” Section 25.2.14 of the ABAQUS Analysis User's Manual).

Figure 15.1–1 Orientation systems.