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How to apply the linear (variable) load to a surface

Dears, I'd like to know how to apply a linear force to a surface, such as water pressure on the surface.
The user menual said that the variable load is not applicable for surface load, but could anybody give me a detailed instruction to apply such kind of load? I'm sorry to post such basic question here cause I am really a newbie. Appreciate for any advise.

 

 

FORCE.jpg

 

 

 

 

2 REPLIES
Solution
Solution
Accepted by topic author Gerry
3 weeks ago

Re: How to apply the linear (variable) load to a surface

[ Edited ]

Use a Data Surface.  In this case, you can use either a Between Coordinates Data Surface, or an Equation Data Surface.

 

For both types, lets assume p1 = 2.5 and p2 = 5.0. applied to one face of a 10 X 10 X 10 cube.

 

For the Between Coordinates Data Surface create the entries for the Data Surface as shown below.

 

Between Coordinates.jpg

 

Then when creating the Pressure Load on the surface, you apply a value of 1 for the Pressure (the multiplier times the value of the Data Surface) and select the Data Surface as shown below.

 

Load using Data Surface 1.jpg

 

For the Equation Data Surface, you should first define a Coordinate System (Csys) as a reference for the values.  In this case, I created a CSys at the base of the cube (CSys 3).  Then, create an Equation Data Surface referencing the Csys as shown below. The characters "!z" refer to the element centroid's Z position.

 

Equation Data Surface.jpg

 

 

After applying the load in both cases, it will appear as follows:

 

Load Applied.jpg

 

When solving, the load is expanded as pressure loads on the element faces and will look like this if you manually expand the load.

 

 Resulting Load Distribution.jpg

Best Regards,
Chip Fricke
Principal Applications Engineer - Femap Product Development
Solution
Solution
Accepted by topic author Gerry
3 weeks ago

Re: How to apply the linear (variable) load to a surface

[ Edited ]

I use Model, Load, On Surface... then I select pressureImmagine 1.png

 then I choose the variable method and I put the equation of the hydrostatic load referred to a proper coordinate systemImmagine 2.png

 

 

 

In this case Femap shows the main constant factor "1" but I think the results are correct.

 

Best Regards

 

 

 

 

AMinati