CONSTRUCT COORDSYS CYLINDRIC

         

This command is used to define a local cylindrical coordinate system.

FEMGEN command

CONSTRUCT COORDSYS CYLINDRIC [csyst] Pnamo Pnamz Pnamx

csyst = name of the local coordinate system, up to 4 characters

Pnamo = origin of coordinate system

Pnamz = defines the local z-axis direction from `pnamo' to `pnamz'

Pnamx = defines the local x-axis direction, which is the vector from `pnamo' to `pnamx' projected onto the plane normal to the local z-axis.

The cylindrical coordinates $(r,\theta,z)$ are connected to the local (x,y,z) coordinates by $x=rcos(\theta)$, $y=rsin(\theta)$ and z=z . Where $\theta$ is in degrees.

Local cylindrical coordinate systems may be selected for use in the definition of point coordinates (in terms of the local cylindrical coordinates r , $\theta$, and z ) using the command CONSTRUCT COORDSYS LOCAL, or for the creation of skew boundary conditions using the command PROPERTY ATTACH

 

Figure 2.1: Definition of a cylindrical coordinate system

Notes:

1.

Default names
If no name is entered a default name is created, this is CSn where n is a count of defined coordinate systems. The default name can be changed with the CONSTRUCT NAME command.

Examples:

1.

CONSTRUCT COORDSYS CYLINDRIC CC1 P1 P4 P7

This creates a cylindrical coordinate system called CC1 with P1 as the origin, P1 to P4 defines the local z-axis and P7 defines the local x-axis.

See also the following commands

'CONSTRUCT COORDSYS LOCAL'
'CONSTRUCT NAME'
'PROPERTY ATTACH'
'UTILITY TABULATE GEOMETRY CSYST'
'UTILITY DELETE GEOMETRY CSYST'

FEMVIEW command

 

CONSTRUCT COORDSYS CYLINDRIC [csyst] def

This command is used to define a local cylindrical system for use with RESULTS TRANSFORM LOCAL

csyst = optional name of the local coordinate system

defn = two sets of model coordinates (x, y, z) defining the local origin and local z axis of the system. OR

= the keyword NODES with two node numbers defining the local origin and local z axis of the system. OR

= X or Y or Z if the axis of the cylinder is one of the global axes.

Each time that a new axis system is created an axis set is drawn at the local origin to indicate the location and orientation of the coordinate system.

When the resulting cylindrical axis system is used with RESULTS LOCAL TRANSFORM the radial (or local x) direction is normal to the surface of the cylinder, the local z direction is in the direction of the cylinder axis and the hoop (or local y) direction is circumferential.

See also the following commands

'RESULTS TRANSFORM LOCAL'
'UTILITY TABULATE '

Examples:

1.

CONSTRUCT COORDSYS CYLINDRIC 1.1 1.2 2.1 3.2 2.1 4

Creates a cylindrical axis system with the origin at x=1.1, y=1.2 and z=2.1. The local z axis of the system passes through x=3.2, y=2.1 and z=4. A name for the system will be generated automatically.

2.

CONSTRUCT COORDSYS CYLINDRIC CONIC1 NODES 1 10

Creates a cylindrical axis system called CYL1 with the origin at node 1, the local z axis defined by node 10.