August 2, 2024 at 7:11 pm
wrbulat
Ansys Employee

Volume 1 appears to be subdivided (sliced) in such a way that there is a fairly sharp angle between the plane of the cut and the inner cylindrical surface. For what reason is the the geometry subdivided in this way? You mentioned contact. Is there contact between one of the surfaces on the right end of the reinforced pipe, with the pipe subjected to an axial load? Did you end up meshing with tetrahedra? If the subdivision was made to clearly define contact surface, I think you can do away with it... the pressure distribution from the contacting body (if you model it explicity) should be fairly well represented.

There are multiple options for defining smeared reinforcing. I believe that in the option you are using, the location and orientation of the fibers is defined with respect to the order of nodes in each element:

If you have a tetrahedral mesh, with random node number order within each element and multiple layers of elements through the thickness of the pipe wall, you might end up with a corresponspondingly random reinforcing locations and orientations.

I can offer you the following (copy the lines below into a text file and read the text file into MAPDL with the /INPUT command). Try two different values of parameter r_reinf (0.001 & 0.0005). The calculated results should differ substantially. I have the luxury of using very simple geometry (not sliced as yours is). Even with this "unfair advantage", I had to resort to a "trick" to align my SOLID185 elements (initially define them to be layered so I could use EORIENT to renumber the elements in such a way as to get consistent REINF265 orientation in the cylinder wall). I added comments to explain the numerous other settings I used in the setup.

Another option would be to create MESH200 elements and assign the reinf section properties to them.

 

I hope this helps!

Bill

 

 

fini
/cle
 
/sys,del file*.png
 
/vie,1,1,1,1
/vup,1,z
 
 
C********************************************************
C*** PARAMETERS
C********************************************************
pi=acos(-1)
 
r1=0.010 ! CYLINDER INNER RADIUS
r2=0.020 ! CYLINDER OUTER RADIUS
l=0.01 ! CLINDER LENGTH
 
r_reinf=0.001 ! REINFORCING FIBER RADIUS (COMPARE 0.001 & 0.0005)
a=pi*r_reinf**2 ! CORRESPONDING REINF CROSS SECTION AREA
facenum=3 ! FACE NUMBER FOR "ELEF" REINF SECTION PARAMETER
s=0.0025 ! REINF SPACING
thta=30 ! MAGNITUDE OF REINF FIBER ORIENTATION ANGLE
 
E_base=0.05e9 ! BASE ELEMENT ELASTIC MODULUS (~RUBBER)
nu_base=0.20 ! BASE ELEMENET POISSON'S
 
E_reinf=2e11 ! REINF ELASTIC MODULUS
nu_reinf=0.20 ! REINF POISSON'S
 
u_top=0.001 ! MAGNITUDE OF AXIAL DISPLACEMENT IMPOSED ON CYLINDER IN TRIAL SOLVE
f_top=2e3 ! MAGNITUDE OF AXIAL FORCE IMPOSED ON CYLINDER IN TRIAL SOLVE
 
 
/title,R_fiber=%r_reinf%, S_fiber=%s%, E_fiber=%E_reinf%
 
C********************************************************
C*** GEOMETRY & BASE ELEMENT MESH
C********************************************************
wpcs,-1,0 ! CYLINDRICAL ELEMENT COORDINATE SYSTEM
cswp,11,1
 
/prep7 ! GEOMETRY (FOUR 90 DEG SECTORS)
cyli,r1,r2,0,l,0,90
cyli,r1,r2,0,l,90,180
cyli,r1,r2,0,l,180,270
cyli,r1,r2,0,l,270,360
numm,kp ! MERGE COINCIDENT KEYPOINTS
vatt,1,1,1,11 ! ASSIGN ATTRIBUTE NUMBERS (MAT, REAL, TYPE, ESYS)
 
et,1,185,,,1 ! LAYERED SOLID185 ELEMENT TYPE
mp,ex,1,E_base ! ELASTIC MODULUS
mp,nuxy,1,nu_base ! POISSON'S
vmes,all ! MESH VOLUMES
 
 
C********************************************************
C*** REORIENT BASE ELEMENTS
C********************************************************
eorient,lysl,posz ! RENUMBER SO THAT FACE 1 IS PARALLEL +Z ESYS AXIS
 
 
C********************************************************
C*** REINFORCING ELEMENT PROPERTIES
C********************************************************
mp,ex,2,E_reinf ! ELASTIC MODULUS
mp,nuxy,2,nu_reinf ! POISSON'S
 
sect,2,reinf,smear ! REINF SECTION FOR INNER RADIUS
secd,2,A,s,,thta,elef,facenum,0.5
seccontrol,0,1,3 ! REMOVE BASE MATERIAL IN DOMAIN OCCUPIED BY REINFORCING, INCLUDE TRANSVERSE SHEAR & BENDING
 
sect,3,reinf,smear ! REINF SECTION FOR OUTER RADIUS
secd,2,A,s,,-thta,elef,facenum,0.5
seccontrol,0,1,3 ! REMOVE BASE MATERIAL IN DOMAIN OCCUPIED BY REINFORCING, INCLUDE TRANSVERSE SHEAR & BENDING
 
 
C********************************************************
C*** CREATE REINFORCING ELEMENTS
C********************************************************
csys,11 ! DETERMINE INNER/OUTER RADII
*get,rmin,node,,mnloc,x
*get,rmax,node,,mxloc,x
 
nsel,s,loc,x,rmin ! REINFORCE BASE ELEMENTS ON INNER RADIUS
esln
esel,r,type,,1
nsle
secn,2
ereinf
 
nsel,s,loc,x,rmax ! REINFORCE BASE ELEMENTS ON OUTER RADIUS
esln
esel,r,type,,1
nsle
secn,3
ereinf
 
 
C********************************************************
C*** MAKE BASE ELEMENT HOMOGENEOUS, PLOT ELEMENTS
C********************************************************
et,1,185 ! CHANGE BASE ELEMENT TYPE FROM LAYERED TO HOMOGENEOUS OPTION
 
esel,s,type,,1 ! MAKE BASE ELEMENTS TRANSLUCENT
/trlcy,elem,0.9
alls
/psy,layr,-1 ! DISPLAY LAYERS (REINFORCING)
/esh,1
/dev,vect,0 ! RASTER FILL DISPLAY
eplo ! PLOT ELEMENTS
/sho,png $eplo $/sho,close $/wait,2
 
esel,s,type,,2 ! SELECT REINFORCING ELEMENTS
/dev,vect,1 ! WIRE FRAME DISPLAY
eplo ! PLOT ELEMENTS
/sho,png,,1 $eplo $/sho,close $/wait,2
 
/dev,vect,0 ! REVERT TO RASTER FILL
esel,s,type,,1 ! MAKE BASE ELEMENTS OPAQUE
/trlcy,elem,0
alls
 
fini
 
 
C********************************************************
C*** TRIAL SOLVE
C********************************************************
/solu
 
nlgeom,on ! MAY BE NECESSARY TO INVOKE TENSION-ONLY REINF BEHAVIOR
 
autots,off
outr,all,all
 
nsel,s,loc,z ! FIX BASE
d,all,all
 
nsel,s,loc,z,l
cp,1,uz,all
nd_top=ndnext(0)
 
alls
 
!d,nd_top,uz,u_top ! TENSION ON TOP SURFACE
f,nd_top,fz,f_top ! TENSION ON TOP SURFACE
nsub,5
solv
 
!d,nd_top,uz,-u_top ! COMPRESSION ON TOP SURFACE
f,nd_top,fz,-f_top ! COMPRESSION ON TOP SURFACE
nsub,10
solv
 
fini
 
 
C********************************************************
C*** POST PROCESSING
C********************************************************
 
/post26
!rfor,2,nd_top,f,z
nsol,2,nd_top,u,z
/axl,y,Axial Displacement
plva,2
/sho,png $plva,2 $/sho,close $/wait,2
 
 
/post1
set,1
 
esel,s,ename,,265
ples,s,x
/sho,png $ples,s,x $/sho,close $/wait,2
 
esel,s,ename,,185
rsys,1
plns,s,z
/sho,png $plns,s,z $/sho,close $/wait,2
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