Learning Forum

[Waleed Khalid]

Hi, guys, 

I am new to Ansys Static Structural.

How can I apply force-free boundary conditions in Ansys Static Structural?

I have defined in User-defined Function  (Stress tenor. normal vector). According to the definition, it must be equal to zero. I am using force-free boundary conditions. I do not apply any condition on the circle. How can I set zero force on the circle?

[SaiD]

Hello,

By force-free, do you mean a traction-free boundary condition? If so, by default, all boundaries on which no boundary conditions are applied explicitly have traction-free boundary condition applied on them. So you don't need to do anything :) If you check the stress on such boundaries, it may not be exactly zero (since this is a numerical solution, not an exact one), but the stress values should be very small.

[Waleed Khalid]

I also agree with you, but my supervisor says it must be equal to zero. he said by definition (Stress Tensor.  normal vector) is = zero. I explained to him default is a free boundary condition.  But he asked me to do this which I explain in the figure. 
He thought this wrong and asked me to use the zero displacement boundary condition. and check whether this is zero or not. But it is zero as I attach a figure in this reply. Can you tell me is there any way to set zero force by using some User defined function or by some importing boundary condition or it is not possible in Ansys?

[SaiD]

I guess you can apply a Force boundary condition to the hole, use a cylindrical coordinate system in the center of the hole and set its radial component to be 0. But again, it's a complicated way of achieving the same simple result :)