*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 ).

**Figure:** 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 ).

**Figure:** 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 .

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
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.