Set nodal-forces

[studdrud]

Hi elmer-team,
i'm using elmer for my studies and it is a great program: many functions and easy to do first computations.
I'm using the elastic sover and now i want to set nodal forces at arbitrary point of my structure. I looked at the tutorial,
solver manual and the model manual but i didn't found anything. How can i set these bc's?

regards rn

[raback]

The following examples might be useful:

To set a force of 1 N in x-direction at the node closest to origin in 2D:

Code: Select all

Boundary Condition 2
  Target Coordinates(1,2) = Real 0.0 0.0 
  Displacement 1 Load = Real 1.0 
End

To set a force of 10 N in z-direction at the node 123 in 3D:

Code: Select all

Boundary Condition 2
  Target Nodes(1) = Integer 123 
  Displacement 3 Load = Real 10.0 
End

I hope I got the syntax right from memory...

BR, Peter

[studdrud]

Thanks raback for the fast answer ;
i've tried the examples, you've posted, using a beam. The beam is 3-d an is at the left side fixed in a wall. the bc i'm using is:
Boundary Condition 1
Target Boundaries(1) = 1
Name = "wall"
Displacement 3 = 0
Displacement 2 = 0
Displacement 1 = 0
End
This is not the problem. At the right side, exactely at the front surface, should be a force in y-direction. I've done this with following bc:
Boundary Condition 2
Target Boundaries(1) = 6
Name = "force"
Force 2 = 50000
End
This problem was computing. But if i choose a node, like you suggested, the solver gets this here:
MAIN: -------------------------------------
MAIN: Steady state iteration: 1
MAIN: -------------------------------------
MAIN:
SolveSystem: Solution trivially zero!
SolveSystem: Solution trivially zero!
SolveSystem: Solution trivially zero!
SolveSystem: Solution trivially zero!
SolveSystem: Solution trivially zero!
SolveSystem: Solution trivially zero!
SolveSystem: Solution trivially zero!
ComputeChange: SS (ITER=1) (NRM,RELC): ( 0.0000000 0.0000000 ) :: linear elasticity
ResultOutputSolver: -------------------------------------
...
I've tried this with the coordinates and with the node. I've tried Forde2=50000 instead of Displacement Load but it doesn't work too.
Do you have some ideas?

Regards rn

[raback]

Ok. It seems that the vector way of defining the load didn't work. You have to do it component-wise. See the updated instructions.

BR, Peter