*ORIENTATION

Keyword type: model definition

This option may be used to specify a local axis system X'-Y'-Z' to be used for defining material properties. For now, rectangular and cylindrical systems can be defined, triggered by the parameter SYSTEM=RECTANGULAR (default) and SYSTEM=CYLINDRICAL.

A rectangular system is defined by specifying a point a on the local X' axis and a point b belonging to the X'-Y' plane but not on the X' axis. A right hand system is assumed (Figure 151).

**Figure 151:** Definition of a rectangular coordinate system
$\begin{figure}\epsfig{file=Rect.eps,width=10cm}\end{figure}$

When using a cylindrical system two points a and b on the axis must be given. The X' axis is in radial direction, the Z' axis in axial direction from point a to point b, and Y' is in tangential direction such that X'-Y'-Z' is a right hand system (Figure 152).

**Figure 152:** Definition of a cylindrical coordinate system
$\begin{figure}\epsfig{file=Cyl.eps,width=10cm}\end{figure}$

Instead of listing the coordinates of points a and b explicitly on the line underneath *ORIENTATION, the user can specify a distribution defined by a *DISTRIBUTION card.

The parameter NAME, specifying a name for the orientation so that it can be used in an element property definition (e.g. *SOLID SECTION) is required (maximum 80 characters).

Notice that a shell ALWAYS induces a local element coordinate system, independent of whether an *ORIENTATION applies or not. For details the user is referred to Section 6.2.14.

For rectangular systems an additional rotation about one of the local axes can be specified on the second line underneath the *ORIENTATION card.

First line:

*ORIENTATION
Enter the required parameter NAME, and the optional parameter SYSTEM if needed.

Second line (explicit definition of a and b):

X-coordinate of point a.
Y-coordinate of point a.
Z-coordinate of point a.
X-coordinate of point b.
Y-coordinate of point b.
Z-coordinate of point b.

Second line (use of a distribution):

name of the distribution.

Third line (optional for local rectangular systems)

local axis about which an additional rotation is to be performed (1=local x-axis, 2=local y-axis, 3=local z-axis).
angle of rotation in degrees.

Example:

*ORIENTATION,NAME=OR1,SYSTEM=CYLINDRICAL
0.,0.,0.,1.,0.,0.

defines a cylindrical coordinate system with name OR1 and axis through the points (0.,0.,0.) and (1.,0.,0.). Thus, the x-axis in the global coordinate system is the axial direction in the cylindrical system.

Example files: beampo2,beampo6.