Learning Forum

[javier.medina.galera]

Hi, I would like to model a tapered beam forming a hollow conical geometry as a transition piece between two cylinders of different diameter. I need it to be a beam type for further calculations in Aqwa.

I'm aware that with APDL you can create a tapered cross section and then assign it to a line. Is there any way to do this in Design modeler or Space claim? Can I run the APDL code inside DM or SC??

Thank you very much.

 

[Erik Kostson]

 

Hi

You can not do that.

 

It is only possible to define the tapered beam inside mechanical using APDL command snippet.

Never done this but perhaps it is possible (see the help manual for tapered beam, e.g., sectype,3,taper, sectype,2,beam, and sectype,1,beam, etc)

All the best

 

Erik

 

[Ankush Choudhary]

Hi Javier,

Spaceclaim, Design Modeler, and Mechanical Gui do not support the tappered beam section. For defining the tapered section, you need to insert the APDL script inside the mechanical.

 

Thanks,

Ankush

[javier.medina.galera]

Hi Erik and Ankush,

Thank you very much for your answers. I've tried to follow your advice but I'm stuck, I'm not familiar with working with snippets or running scripts inside mechanichal so I may be missing something.

I've written this APDL script that generates my desired geometry:

FINISH

/CLEAR ! clear database

/PREP7 ! enters the preprocessor

! MATERIAL PROPERTIES

YNGMOD = 2e11 ! Young's modulus

PCOEF = 0.27 ! Poisson coefficient

MDENS = 7850 ! Material density

! SECTION DIMENSIONS

! CTUBE1

Intrad1 = 6470

Extrad1 = 6500

!CTUBE2

Intrad2 = 9370

Extrad2 = 9400

! Element types

ET,1,BEAM189 ! create 3-node beam element

ET,2,SHELL281  

!define material

MPTEMP,,,,,,,,

MPTEMP,1,0

MPDATA,EX,1,,YNGMOD ! Young's modulus

MPDATA,PRXY,1,,PCOEF ! poisson coef.

MPDATA,DENS,1,,MDENS  ! Density. For considering own weight

! Keypoints Definition

K,1,0,0,0

K,2,0,0,-4000

K,3,0,0,-12000

K,4,0,0,-120000

K,5,0,0,10000

SECTYPE,1,BEAM,CTUBE,CT,0

SECOFFSET, CENT ! Origin of section located at CoG of section

SECDATA,Intrad1,Extrad1,64,0,0,0,0,0,0,0,0,0 ! Variables of section

LSTR,1,2! Straight line connecting each KP

LSEL, , , ,       1 ! Selecting the generated line

LATT,1, ,1, ,       , ,1   ! Assigning the variable section, element type and material properties to line

LESIZE,1,400 , ,, , , , ,1  ! Size of Mesh

LMESH,      1  ! Line Meshing

SECTYPE,2,BEAM,CTUBE,CT,0

SECOFFSET, CENT ! Origin of section located at CoG of section

SECDATA,Intrad2,Extrad2,64,0,0,0,0,0,0,0,0,0 ! Variables of section

LSTR,3,4! Straight line connecting each KP

LSEL, , , ,       2 ! Selecting the generated line

LATT,1, ,1, ,       , ,2   ! Assigning the variable section, element type and material properties to line

LESIZE,2,800 , ,, , , , ,1  ! Size of Mesh

LMESH,      2 ! Line Meshing

LSTR,2,3! Straight line connecting each KP

SECTYPE,3,TAPER, ,TC   ! We define a taper to generate a variable section. Tower's transition piece.

SECDATA,  1 ,0,0,-4000, ! Initial base of variable section

SECDATA,   2,0,0,-12000,

LSEL, , , ,       3 ! Selecting the generated line

LATT,1, ,1, ,       , ,3  ! Assigning the variable section, element type and material properties to line

LESIZE,3,400 , ,, , , , ,1  ! Size of Mesh

LMESH,      3 ! Line Meshing

! Upper section

K,5,0,0,10000

LSTR,1,5! Straight line connecting each KP

LSEL, , , ,       4 ! Selecting the generated line

LATT,1, ,1, ,       , ,1   ! Assigning the variable section, element type and material properties to line

LESIZE,4,1000 , ,, , , , ,1  ! Size of Mesh

LMESH,      4 ! Line Meshing

/ESHAPE,1.0

And the result is

 

Actually, the part of the code I would like to implement is this, where I define a tapered section from the sections already defined above for the rest of the line bodies:

LSTR,2,3! Straight line connecting each KP

SECTYPE,3,TAPER, ,TC   ! We define a taper to generate a variable section. Tower's transition piece.

SECDATA,  1 ,0,0,-4000, ! Initial base of variable section

SECDATA,   2,0,0,-12000,

LSEL, , , ,       3 ! Selecting the generated line

LATT,1, ,1, ,       , ,3  ! Assigning the variable section, element type and material properties to line

LESIZE,3,400 , ,, , , , ,1  ! Size of Mesh

LMESH,      3 ! Line Meshing

What I've tried so far:

• Use design modeler to build the line bodies and the two CTUBES, transfer the geometry to a mechanichal model (tried to implement the snippet by inserting an apdl command to the desired line body, but it doesn't make any change) and then to the hydrodynamic diffraction module.
• Archive the apdl model and load it in workbench using the external model option, but workbench is reading the the tapered section as a constant CTUBE equal to the start of the tapered section
• Use the spaceclaim 'extract' option under 'prepare' tab to extract the tapered section, but the hydrodynamic difraction doesn't like it

I would really apreciate if you could help me implementing the code inside mechanichal. Thank you very much for your help.

 

Best regards,

Javier

[Erik Kostson]

 

 

 

Hi

 

Have not used this much and it is not really convenient.

So the way to use it in WB / mech. (define 3 line bodies/geom., and then change the section of the taper as shown in the apdl command snippet placed under it in the tree below).

 

 

We can not view it (taper) in mechanical ui – so only way is in APDL (used an image to view it – see below)

The last snippet is:

/eshape,1,ON
/SHOW,png
EPLOT
/show,close