GiD forum

Hi,

I am using Code_Bright and have some queries regarding the X and Y direction prescribe, what are the conditions when we use Nodal force and boundary stress. In some tutorials Nodal force is used to prescribe X and Y direction (i,e. in Shallow foundation tutorial) while in some others Boundary stress is applied (i.e, in HM “Mockup-test”problem). Could you please give some idea about these conditions.

Beyond this what is the difference in Boundary flow rate and Volume flow rate in Surface Flux B.C.

Does the difference in these conditions make some major difference our simulation results.

Thank you,

-Kevin

Dear Kevin,

Nodal forces imposes the force in the nodes with the same value, whereas boundary stress imposes the force weighted by the area afected by every node. For example, in an structured mesh the nodes in the corner will affect half the surface than the other nodes. Anyway, it is difficult to explain by message, but the point is that to prescribe X and Y direction it doesn't matter very much which one you choose. However, for forces/stresses applied in a boundary, normally you should use 'boundary stress'. For prescribing displacements you can use nodal forces if you want.

About volume flow rate, it is generally intended for volumes, not surfaces.

Anyway, you can make models comparing different set-ups if you want. Feedback about it would be wonderful.

Regards,

Alfonso