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Mapping Pressure Loads onto 3D Surface

Mapping Pressure Loads onto 3D Surface

Mapping Pressure Loads onto 3D Surface

(OP)
Hello,

I have pressure data in excel in the form of (x,y) coordinates and pressure magnitude, pressure will be applied in one direction only. I would like to "project" the pressures onto the 3D surface without considering the z coordinate of the nodes. There must be a way to do this, likely using a data surface. Does anyone know how?

“The most successful people in life are the ones who ask questions. They’re always learning. They’re always growing. They’re always pushing.” Robert Kiyosaki

RE: Mapping Pressure Loads onto 3D Surface

see the YouTube video "load spreading in FEMAP"

another day in paradise, or is paradise one day closer ?

RE: Mapping Pressure Loads onto 3D Surface

Use "Arbitraty 3D Data Surface". Create two sets of points with Z1 and Z2 coordinates that your model stay inside these points.

RE: Mapping Pressure Loads onto 3D Surface

(OP)
karachun. I was trying to do something similar, but couldn't quite make it work. Can you expound?

“The most successful people in life are the ones who ask questions. They’re always learning. They’re always growing. They’re always pushing.” Robert Kiyosaki

RE: Mapping Pressure Loads onto 3D Surface

MegaStructures
Actually I tried to interpolate pressures in the test case and noticed that the results are not very good. Better not to use my previous advice.

I have some thoughts on how to elegantly solve this problem but I need some small and simple test examples from you. I need a surface, mesh and table with points to interpolate.

RE: Mapping Pressure Loads onto 3D Surface

guys, we don't need to reinvent the wheel. FEMAP already has procedures to apply a pressure "surface" (like pressures generated from a CFD mesh of a surface) to a FEMAP mesh of the surface. see previous post of YT video.

another day in paradise, or is paradise one day closer ?

RE: Mapping Pressure Loads onto 3D Surface

rb1957

This is true but if we consider the worst scenario: non flat surface and random number of points instead of four values at corners.
In this case ve can not use Parametric table or Along coordinates.

Here is another variant:
1. Assume that our surface has Z coordinates between z1 and z2.
2. Prepare in Excel table. Write all data points and x,y coordinates. Use z1 as Z coordinate.
3. Copy these cells to the end of the table and change Z coordinate to z1+1mm or other small value until you reach z2.
4. Load this cumulative table into Femap as Arbitrary 3D Data Surface.

Now we have Spatial field of variable and if we interpolate values in any point inside this field, result vill be almost insensitive from the Z coordinate.

RE: Mapping Pressure Loads onto 3D Surface

I'm used to CFD producing pressure results at each grid point, we can speculate about "worst case" scenarios but I don't have time.

So long as we have two sets of points on the same surface (say one CFD mesh and another FEA mesh) then FEMP can project the CFD onto the FEA.

another day in paradise, or is paradise one day closer ?

RE: Mapping Pressure Loads onto 3D Surface

rb1957

I agree that if you have results from other mesh, like CFD solution and we have X,Y and Z coordinates of data points then we can easily interpolate them.

If I understand correctly we have only X and Y coordinates and have no info about Z coordinate and we have some random non flat surface with mesh. Interpolation takes into account distance from data points to elements or nodes. Now if you place the Z coordinate far away from the actual position (Z>>X, Z>>Y) of the node or element then all of the data points will have almost the same distance and interpolation will give wrong results.


BlasMolero
Hello, Blas. Have you seen this topic?
/viewthread.cfm?qid=486710

RE: Mapping Pressure Loads onto 3D Surface

I don't understand your situation.

Have you hi-jacked Megastructures thread (with your own problem)?

another day in paradise, or is paradise one day closer ?

RE: Mapping Pressure Loads onto 3D Surface

No, it is only my understanding of OP question.

Maybe better to wait for MegaStructures ansvers. Things may be not so complicate.

RE: Mapping Pressure Loads onto 3D Surface

ah ! I see ... none so blind as those that will not see !

reread the OP. Agree wait for OP to clarify. It sounds like he has pressures on a projection of a surface (trying to wrap my mind around that !?).

but each of his (x,y) points can be projected/plotted onto his surface, which would give him a set of points on his surface which FEMAP can apply to his FEM mesh.

another day in paradise, or is paradise one day closer ?

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