force application on curved area in specific direction.

[Roberto83]

Hello everyone,
I am performing a study in ansys 12(mechanic apdl) of a mechanical hook.
I should apply a force in x direction,distributed on the surface (1/4 cylinder), which corresponds to the hole in which the pin is inserted.
not being required the study of the hole-pin contact, I hypothesized a constant-type force distribution, deriving from the contact of the pin with the hole in which it is inserted.
the problem is that I should apply a force on the area, but in a definite direction.
How can I do that?
Forgive me the question (I believe banal to most users), but they are to 'prime weapons' with ansys.

 

[Roberto83]

no kind soul willing to give me a hand?:frown:

 

[sciolingelao]

Hello, roberto.
Forgive me but in my humble opinion the road you are following is not the most correct.
In my opinion, as far as my proposal may seem very boriotic, it would convelop you, in order to obtain congruent results, to go to shape the contact pin / mouth.
this because from an algorithmic point of view, the problem of contact falls into the category of non-linear problems for geometry.
at different levels of the load correspond tensions that are not, among themselves, in linear proportion to the loads. the solution arises in these cases from an iterative process.
It is true, the single step is linearized but it is also true that the matrix of coefficients of balance equations is updated from time to time.
So I think you're going to have to make some extra sacrifices, but you'll certainly get a more truthful result from your calculation than what would make you a " too linearized" approach.
Hi.

 

[Roberto83]

Hi, charlie.
first of all thank you for having responded, very kind.:smile:
Yes, I know very well that my approximation is extremely ideal, and if we also want misleading, but after having discussed it with the professor, who follows the project, has approved my decision, and therefore, at least on this particular I can save time and work.
Can you tell me the way to model and apply the required load?
I also thought I would apply a force on every node of the interested surface, but how to do it? Surely there are more practical and simple roads. .
Forgive me again for trivial questions, but on the practical level in ansys are in the learning phase.

Thank you very much.
roberto

 

[sciolingelao]

I understand at this point that your problem is: how do I extrapolate knots from my model?
Right?
brutal response: menu > select entities
pop-up appears to the right of your audition.
from there you can select your knots with the selection criteria that you will find most suitable, to apply them the loads you want.
of course the above must necessarily follow the mesh phase of your model. . .
Listen, I don't know if this can help you: usually to study the trends of tensions in the hooks (i.e....your case ) I referred to the theory of the beams of great curvature (author feodosev, title: strenght of materials ed. mir)... university reminiscences that occasionally return me useful!
This can help you understand if and how much you've been disconnected from the "mathematics" solution of the problem!
Hi.

 

[Roberto83]

Hi, charlie.
Yes, you have centered the problem..I would have to select all the knots that belong to the indicated area, and on them apply a force in direction x.
I thought there was a function already implemented to do that.
I tried to run the select<entities command, but I can't select the area, and then the knots that belong to it. Can you be more precise?

Thanks again for the help and patience.

 

[sciolingelao]

define " element type "
define " real constants "
define "material props "
run the mesh phase of the model
bind your model
main menu > plot > areas
main menu > plotctrls > numbering > flag popped on area
take note of the id of the area in question
main menu > select entities
in the pop up you can select " nodes " and " attached to " flag on " areas, interior
then solution >apply >structural >force/moment > on nodes > pick all > in pop up choose direction and magnitude
Hi.

 

[Roberto83]

define " element type "
define " real constants "
define "material props "
run the mesh phase of the model
bind your model
main menu > plot > areas
main menu > plotctrls > numbering > flag popped on area
take note of the id of the area in question
main menu > select entities
in the pop up you can select " nodes " and " attached to " flag on " areas, interior
then solution >apply >structural >force/moment > on nodes > pick all > in pop up choose direction and magnitude
Hi.

Thank you very much.!