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CONSTRUCT SCURVE [scurve] SURFACE Type Parameters

   

This command is used to define a space curve which varies over a surface. The user may specify a value at each corner of the surface or an individual line space curve for one or more of the surface's edges.





Type Parameters
CORNERS a1, [a2, [a3, [a4]]]
LINE L1 Parameters as for line space curve except LIST FILE
L2 Parameters as for line space curve except LIST FILE
L3 Parameters as for line space curve except LIST FILE
L4 Parameters as for line space curve except LIST FILE


scurve = name of the space curve
a1-a4 = amplitude of space curve at corner n
L1-L4 = Local side identifier for surface


 
Figure 2.31: Definition of a surface CORNERS space curve
\begin{figure} \centerline{ \psfig {figure=diagrams/scs1.ps,width=5.0in} }\end{figure}


 
Figure 2.32: Definition of a surface LINE space curve
\begin{figure} \centerline{ \psfig {figure=diagrams/scs2.ps,width=5.0in} }\end{figure}

Notes:

1.
Valid range
When the space curve is defined using the sides rather than the corners, the space curve is only valid in the range between Umin and Umax for each side.
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 surface 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 surface load mask will compress a surface space curve so that all of the curve fits within the load mask limits. A global load mask will truncate a surface space curve.
5.
List space curves
There is a limit of four data points (ie 8 values) on a LIST type space curve under the SURFACE LINE option.
6.
Viewing space curves
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 L1-L4.
7.
Evaluation of SURFACE CORNERS space curves
The space curve value for these curve types is evaluated by linear interpolation of the values a1-a4 over the surface.

8.
Evaluation of SURFACE LINE space curves
The evaluation of SURFACE LINE space curves varies according to how many and which lines on the surface have been assigned a curve.


 
Figure 2.33: Evaluation of SURFACE LINE space curve
\begin{figure} \centerline{ \psfig {figure=diagrams/scsla.ps,width=5.0in} } \end{figure}

9.
Permitted surface topologies
The surface space curve can only be applied to four-sided surfaces with the topologies indicated in the following figures. The sides of the surfaces can be combined lines.


 
Figure 2.34: Flat surface with four straight sides
\begin{figure} \centerline{ \psfig {figure=diagrams/lmsurfa.ps,width=2.8in} }\end{figure}


 
Figure 2.35: Flat surface with two straight sides and two constant radius arc sides
\begin{figure} \centerline{ \psfig {figure=diagrams/lmsurfb.ps,width=2.8in} }\end{figure}


 
Figure 2.36: Cylindrical surface with two straight sides and two constant radius arc sides
\begin{figure} \centerline{ \psfig {figure=diagrams/lmsurfc.ps,width=2.8in} }\end{figure}


 
Figure 2.37: Flat surface with one constant radius arc and one degenerate side
\begin{figure} \centerline{ \psfig {figure=diagrams/lmsurfd.ps,width=2.8in} }\end{figure}

Examples:

1.
CONSTRUCT SCURVE SC1 SURFACE LINE L1 NORMAL 3
CONSTRUCT SCURVE SC1 SURFACE LINE L2 LIST 0 1 1 0


 
Figure 2.38: SURFACE LINE space curve
\begin{figure} \centerline{ \psfig {figure=diagrams/scsle.ps,width=5.0in} } \end{figure}

See also the following commands

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

next up previous contents index
Next: CONSTRUCT SET Up: CONSTRUCT SCURVE Previous: CONSTRUCT SCURVE [scurve] LINE Type Parameters

Femsys Limited
1st October 1999