CONSTRUCT SCURVE [scurve] GLOBAL X/Y/Z Type Parameters

   

This command is used to define a space curve for use with any load. The space curve is specified in terms of the global X, Y, and/or Z axes. A space curve may be defined in more than one axis by repeating the command with the same space curve name and a different direction. The curve may be defined as a list of position, magnitude pairs or via a function (e.g. Normal Distribution, Parabola etc.). Lists may be read in from a file or typed in at the keyboard; functions are defined interactively using a small number of control parameters.

A local coordinate system may be attached to the global space curve using the FEMGEN command PROPERTY ATTACH. This will modify the space curve location and the orientation of the space curve limits.

scurve = name of the space curve

X = space curve is defined in the global X axis

Y = space curve is defined in the global Y axis

Z = space curve is defined in the global Z axis

Type = see line space curve for available types

Parameters = see line space curve relevant parameters Note that parameters Umin and Umax should be specified in global coordinates

 

Figure 2.19: Definition of a global space curve in the X direction

Notes:

1.

Valid range
The space curve is only valid in the range between Umin and Umax.

2.

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

3.

Interaction with loads
A global space curve will multiply a load at a node, element face centroid or element centroid (depending upon the load type) by the value of the space curve at that point in space.

4.

Interaction with load masks
A global load mask will truncate a global space curve.

5.

Viewing space curves
Global space curves may be viewed either by applying them to a load and using the command LABEL MESH LOADS or by using the command UTILITY GRAPH SCURVE X,Y,Z.

6.

Evaluation of GLOBAL space curves
The value of the space curve is calculated as S = f1(x) * f2(y) * f3(z).

7.

Permitted surface topologies
All surface topologies including sets are supported.

Examples:

1.

CONSTRUCT SCURVE GLOBAL X ELIPSE 1 23.1 47.6

This creates a space curve on the global x axis starting at x=23.1, ending at x=47.6 with peak amplitude of 1.0.

2.

CONSTRUCT SCURVE SC1 GLOBAL X ELIPSE 1 40 70
CONSTRUCT SCURVE SC1 GLOBAL Y LIST 0 1 90 1
CONSTRUCT COORDSYS CYL CY1 P1 P6 P2
PROPERTY ATTACH SC1 CY1

This creates a space curve in two of the global directions. A local cylindrical axis system is defined and attached to the space curve changing the X direction to be radial and the Y direction to be rotational.

 

Figure 2.20: Definition of a global space curve with local coordinate system

See also the following commands

'CONSTRUCT NAME'
'CONSTRUCT COORDSYS'
'CONSTRUCT LMASK'
'CONSTRUCT TCURVE'
'PROPERTY ATTACH'
'PROPERTY LOAD'
'UTILITY DELETE'
'UTILITY TABULATE'