Command(s):SFFUN
GUI: Main Menu> Preprocessor> Loads> Define Loads> Settings> For Surface Ld> Node Function
Main Menu> Solution> Define Loads> Settings> For Surface Ld> Node Function
It is useful when you want to apply nodal surface loads calculated elsewhere (by another software
package, for instance). You should first define the function in the form of an arra y parameter containing
the load values. The location of the value in the arra y parameter implies the node number. For example,
the arra y parameter shown below specifies four surface load values at nodes 1, 2, 3, and 4, respectively.
=
Assuming that these are heat flux values, you would apply them as follows:
*DIM,ABC,ARRAY,4! Declares dimensions of array parameter ABC
ABC(1)=400,587.2,965.6,740! Defines values for ABC
SFFUN,HFLUX,ABC(1)! ABC to be used as heat flux function
SF,ALL,HFLUX,100! Heat flux of 100 on all selected nodes,
! 100 + ABC(i) at node i.See the Command Reference for a discussion of the *DIM,SFFUN, and SF commands.
The SF command in the example above specifies a heat flux of 100 on all selected nodes. If nodes 1
through 4 are part of the selected set, those nodes are assigned heat fluxes of 100 + ABC(i): 100 + 400
= 500 at node 1, 100 + 587.2 = 687.2 at node 2, and so on.
NoteWhat you specify with the SFFUN command stays active for all subsequent SF and SFE
commands. To remove the specification, simply use SFFUN without any arguments.2.5.7.3. Specifying a Gradient Slope
You can use either of the following to specify that a gradient (slope) is to be used for subsequently
applied surface loads:
Command(s):SFGRAD
GUI: Main Menu> Preprocessor> Loads> Define Loads> Settings> For Surface Ld> Gradient
Main Menu> Solution> Define Loads> Settings> For Surface Ld> Gradient
You can also use this command to apply a linearly varying surface load, such as hydrostatic pressure
on a structure immersed in water.
To create the gradient specification, specify the following:
- The type of load to be controlled (the Lab argument)
- The coordinate system and coordinate direction in which the slope is defined (SLKCN and Sldir, respect-
ively) - The coordinate location where the value of the load (as specified on a subsequent surface load command)
is in effect (SLZER)
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