Algor and surface force

[mirred]

Hi,

I have a little question about surface force.

I have a plane (a sheet metal with tickness 3 mm) 2800x5000 mm and I want to apply 100000 N.

Steps:

1. I mesh (without problem)

2. I decide the position of constraints (without problem)

3. I select the top face of sheet and put the force .... PROBLEM ....  I select SURFACE FORCE and put 100000 N.

4. Start simulation (STATIC)

5. Read the solution: very strange ...  hmmm .... I think:"100000 N over al face or 100000 N for every point of mesh?????"

What should I choose to put my 100000 N over sheet metal?

thank's

mir

[S.LI]

For users, surface force in Algor is the force applied on a surface, not nodes. Of course, in simulation, code will automatically distribute the surface force to nodes.

Another way to apply surface force is "pressure". In this way, users have to calculate pressure value by themselves (pressure = surface force / surface area).

I believe that your model setup is all right. Just don't know why and how strange your results are.

[mirred]

Ok ... I supposed  this.

But I have problems ....  Is i used Surface force I have a strange solution (test.ZIP) .... downward force and deformation up 🙂

Is I used pression:

100000 N / (5000x2800) mm2 = 0.007708 N/mm2 (two.bmp)

The solution is .... NO STRAIN / STRESS!

where is my mistake!!

bye

mir

[xli]

mir,

As your described it looks very like a wrong behavior of software. Either resulting 100000 element pressure or 100000N nodal forces is wrong. If you can attach a static figure of that strange model results and tell us what analysis type (linear stress or MES?) and what kind of element type is (brick or plate/shell?); or if you can share the model with us that would be a great help to us identifying the trouble. Thank you so much.

-xli

At this point, I only have a guess there might be something wrong with the language you are using, it might be not supported and related unit system caused problem...

[S.LI]

Can not obtain enough info from your attachments.

I just put one simple model here to show how surface force works. Hopefully it's helpful.

Usually, surface force just works fine for me.

[mirred]

Ok ... but my example is very big .... I realized another little example.

I have a sheet metal (100x50 mm) with tickness 5 mm.

first test

surface force = 1000 [N]

results: Von mises max = 9.556 [N/mm2]; shift max = 0.001406 [mm]

second test

pression face = 1000 [N] / (100x50) [mm2] = 0.2 [N/mm2]

results: Von mises max = 0.0000 [N/mm2]; shift max = 0.0000 [mm]

???? but I thought to find ugual solution !!!

[mirred]

sorry ... in the first test i find this solution

Von mises max = 4.806 [N/mm2]; shift max = 0.0010226 [mm]

[S.LI]

Do you mean "surface force" works, but "pressure" does NOT?

I tested your model on my machine, WinXP-64 with Algor 2011.00.00.0111.

It works fine, and the results match what you said here.

So I believe it's not the solver's problem. What's the OS in your machine?