Help with defining moment/Finite elements

[sicro]

Sorry for my bad English, I'm Romanian...

 

So, I've got a homework where im supposed to define a moment along the inner contour of a ring like plate. -see 1st picture-

 

The problem is that I could find a program that allows me to do that... Ansys only lets me define the moment in the Cartesian Coordinate System, not the Cylindrical one, and thus the moment doesn't deform the plate like in the picture, but in a different way -see picture 3-. I had to build the 2nd ring in order to define the moment vector direction along Z, because originally the program would only accept a direction that is the same with the axis of the hole and made the moment act like it were spinning the inside ring. -see picture 4-

 

Any ideas?

 

Any help would be really appreciated...

[darkenlighten]

Usually can you select along the surface and not normal to the surface. Can you show the advanced options? I would say see if there is an option to select about the face. This should be an easy task, you might be missing something or this program is lacking.

[sicro]

Sorry, I dont understand... what advanced options?related to what? because there are General program options, moment options, coordinate system options...

[darkenlighten]

I was referring to your screenshot. So the moment advanced options.

 

I would like to help, but I dont have specific experience with ANsys, (I have experience with NX Unigraphics, Solidworks and Autodesk Inventor), so I will do what I can.

 

Also this is a great website for engineering: General: http://eng-tips.com/ For ANsys: http://eng-tips.com/threadminder.cfm?pid=569

[sicro]

Ok, sorry for the confusion.... this is what you can select in the moment options area, besides what you see in the first ScreenShots... the problem is that it wont let me select the other Coordinate System..

 

Thank you very much for the links, too!

[darkenlighten]

For the "Define by" option, what can you select. There should be a way to select about the face, the coordinate system you are in should matter.

[sicro]

I can select define by Vector/ Components in that area.

 

Vector -- I have to choose a direction. If I place the mouse on the inner contour, the direction=axis of the hole and thus the moment rotates the inner contour instead of bending it. I cannot change that vector and make it parallel to the surface... So I've made a 2nd ring and when i choose its inner contour the vector is parallel with the first plate's surface. However, in this case, the moment acts how you see in the strain diagram, not how it should..

 

The 2nd option is choosing "define by components", which also doesn't work, because if the moment is defined by X/Y component, it doesn't uniformly bend the ring upwards.

 

If it would let me define it in a cil. CS it would be ok, but ...

Edited April 28, 2010 by sicro

[darkenlighten]

So when you select the axis of the inner contour, what results are you getting, can you post the analysis on that?

 

And what are your current restraints/fixed surfaces?

[sicro]

The outter contour is fixed.

 

When I select the axis, according to the Vector direction rule, the moment spins the surface like a wheel, it doesn't pull the inner surface outward. Thus, the deformed plate looks like the original plate -completely flat-, not like a "space ship".