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# Interpolate pressures using data surface

Creator

Dear all,

Currently I'm trying to interpolate pressures on a curved cut surface. The pressures in the corners are given (101,325 kPa on angled side, 382,576 kPa on straight side).

I want FEMAP to interpolate all values between these four points on the surface.

When I use Between coordinates data surface, and use Force (because I can't interpolate pressure from data table?), FEMAP gives an error stating:

Unable to create 30 Load(s) on Node(s).  Locations in Data Surface evaluate to zero or are outside the extents of the Data Surface.

If there is any other way to interpolate the pressures between the curved cut surface I would be pleased to know, and/if there is a possibility to interpolate all nodes.

See attachment for the problem.

Kind regards,

René

2 REPLIES 2

# Re: Interpolate pressures using data surface

Siemens Phenom

Looking at this, I first thought of running a NASTRAN Steady Steady Heat Solve, with the one side at 0.1, and the other side at 0.3, you can substitute in your exact values.  I made a similar model, with a skewed patch on the surface of a cylinder. Running this analysis the resulting temperature distribution is -

You then need to convert the nodal temperature data to elemental, (Model - Output - Process) and then you can create a pressure load from this output (Model - Load - From Output)

The other way is to use geometry, if you don't have the geometry for this mesh, use Geometry - Surface - From Mesh, and fit a surface to your mesh.  Make sure you turn off the "Delete Elements" option while creating the surface, you should get a nice 4-sided surface -

Now, use FEMAP's Data Surface Editor, create a "Between Coordinates" data surface, but create a 4-Point Parametric Data Surface, and, under options, select the surface as the parametric driver -

And then for the data surface itself, pick the four corners and enter your pressure values -

Now, when you create your pressure load, you can choose this data surface -

and for each element, FEMAP will interpolate on this data surface, in the parametric space fo the surface and give you a nice distribution -

You might even want to use the "Corners" option to take advantage of NASTRAN's PLOAD4 card which will put a different pressure in each corner of an element -

And you will get -

Mark.

# Re: Interpolate pressures using data surface

Creator

Thanks Mark it works! Lifesaver