beginer help with modeling

[ChessFalconer]

I have been studing ANSYS documentation for nearly 40 days.(i.e. all Alberta online doc and others) But I have a lot of problems modeling because the programs crasshes or simply doesn´t do what it was supose to... I know people use CATIA for modeling...
I hate modeling with ansys... do you recomend me to study catia? or there is a better way. thanks

 

[JakeRAD]

ANSYS is not a good choice for cad modeler.
any other program would be better, and CATIA is the top.
I use CATIA for preparing the surfaces for the model to be meshed and analyzed.
However, catia has a very steep learning curve, and without proper learning materials, you will get lost very fast.

 

[cbrn]

Hi,
as discussed many times, ANSYS' modeler is not intended to be a CAD: it is just meant to be a modeler for FE-oriented models.
That said, I think that everybody recognizes that Ansys Classical still uses a VERY old approach to solid modeling; some operations such as booleans are perhaps the worst in absolute you can find in the market today.
Nevertheless, I find it strange that your program "crashes or doesn't do what it is supposed to": I believe its logics are difficult to understand and often very frustrating (I repeat, boolean algorythms are very "primitive" and frequently won't allow you at all to do what you'd like, e.g. with degeneracies - see help), but crashing ?!? Well, sometimes the Classical GUI "freezes" the selection box, so that you have to "reset" it by Shift+Ctrl+Del, but apart this I never had any other problem.
Of course, modeling with a today's CAD is totally another thing (an airplane instead of a bike). But you'll have to cope with what is available at your workplace... And moreover, then you'll have to transfer the model into Ansys (which opens the path to import troubles...).
Btw: Ansys has a modeler in the WorkBench suite, which I've been told is not so bad, but requires a license.

Regards

 

[ChessFalconer]

Ok it seems there are two solutions the powerfull catia and maybe the more esasy to try the workbench. Personaly I will try both because I need a solution right now but also I want to learnt.

cbrn thanks for the answer!
One example where ANSYS doesn't do what it is supposed to: I make a cylinder a big one and I want to make six holes perpendicular to the axis (I use small cylinders as "drills") then ANSYS make five perfect holes but not six. I solved this with comand line. This can be and exaple of boolean problems you said before

Ansys crashes in my pc sometimes in the meshing job, i think can be a particula case of bad defined geometry


thank you very much i will try both solutions, any sugestion is very apreciated

 

[meshparts]

Hi,

I would say, Ansys classic modeller is primitive but it works very fine, if you learn how to use it. I'm pretty shore, it will be no problem to make 6 holes in one cylinder. Why don't you post your code here? I would take a look at it...

If Ansys crashed in the meshing job, than it's probably a problem of bead geometry (like you said) or bad mesh size (too small or too big).

Regards,
Alex

 

[ChessFalconer]

hi mihaiupb

1) The problem making 6 holes in one cylinder is using de gui, making the holes with command lines there is no problem (in my experice). This is one of my fist step in ANSYS, I have no particular interest in this problem because I solved it after using commands (I like lgw files ) I give you the code because you asked about and if you want to see it.
2) The crashing of ANSYS I think is because of bad geometry (I tried varios mesh size). At this time I don´t know more and I´m going to face the geometry problems first.

thank yor very much for the answer.


For everybody and about this thread:

I´m very interested to get into FEM world no mater the number of programs to study (I have much time, and much interest), someone advised me this:

geomtry: CATIA
mesh: I-deas

all ideas comments about this are more than wellcome thank you very much


the code for mihaiupb:
--------------------------------------

/BATCH

! CYL4,0,0,0.5,0,0,360,25
/prep7
CYL4,0,0,5,0,3.5,360,54
cyl4,0,0,0.5,0,0,360,25

CSYS,0
DSYS,0
CSYS,5
FLST,3,1,6,ORDE,1
FITEM,3,2
VGEN, ,P51X, , , ,90, , , ,1

CSYS,1
FLST,3,1,6,ORDE,1
FITEM,3,2
VGEN,6,P51X, , , ,60, , ,0

FLST,2,3,6,ORDE,3
FITEM,2,3
FITEM,2,5
FITEM,2,7
VADD,P51X
FLST,2,3,6,ORDE,3
FITEM,2,2
FITEM,2,4
FITEM,2,6
VADD,P51X
CSYS,0
FLST,3,1,6,ORDE,1
FITEM,3,3
VGEN, ,P51X, , , , ,27, , ,1

FLST,3,1,6,ORDE,1
FITEM,3,8
VGEN, ,P51X, , , , ,27, , ,1

FLST,3,2,6,ORDE,2
FITEM,3,3
FITEM,3,8
VGEN,2,P51X, , , , ,2.617, ,0

FLST,3,2,6,ORDE,2
FITEM,3,3
FITEM,3,8
VGEN, ,P51X, , , , ,-2.617, , ,1

FLST,3,2,6,ORDE,2
FITEM,3,2
FITEM,3,4

FLST,3,2,6,ORDE,2
FITEM,3,2
FITEM,3,4
VGEN, ,P51X, , , , ,2.617, , ,1

FLST,3,2,6,ORDE,2
FITEM,3,3
FITEM,3,8
VGEN, ,P51X, , , , ,-2.617, , ,1
! /REPLO
! /REPLO
FLST,3,2,6,ORDE,2
FITEM,3,3
FITEM,3,8
VGEN,2,P51X, , , , ,5.234, ,0

FLST,3,2,6,ORDE,2
FITEM,3,3
FITEM,3,8
VSBV, 1,P51X

FLST,3,2,6,ORDE,2
FITEM,3,5
FITEM,3,-6
VSBV, 7,P51X

FLST,3,2,6,ORDE,2
FITEM,3,2
FITEM,3,4
VSBV, 1,P51X


Thank you very much