Hi all,
I have a simple solid model which is statically loaded on one node on top of the structure, subjected to several load steps. The (nodal) loading was obtained using (a much longer structure) LS-Dyna. I would like to obtain the stresses on the Ansys model. So the Ansys model is only a small part of the actual problem, as a result there are no actual constraints on this small part. I am using Inertia Relief.
(Background: I am going to calculate the fatigue on stress concentration points of a pump which is located on a very long riser. LS Dyna calculates the nodal forces, displacements of the riser which is subjected to flow under water. In the Ls dyna model the geometric details are not given. I now model a pump in Ansys, which might be located on this riser, and subjected to the section forces calculated by LS Dyna.)
My question is how to understand if the results are correct? I would like to know with the inertia relief on, am I supposed to see deformation?
Regards,
Bilim
finish
/uis,msgpop,3 ! only show error messages
/clear
/FILNAM,riser
/PREP7
!----------variables--------!
h_pump = 5, ! height of the pump
h_ring = 1,
inner_rad = .3,
outer_rad = .5,
outer_rad_ring = 1,
th_riser=outer_rad-inner_rad,
el_size = (outer_rad-inner_rad) ! # of elements on the smallest line
!------location of the pump
l_riser = 1000 !length of the riser
l_higher=.2 !from the top (sea surface)
l_lower=970 !from the bottom (ground)
!---------------------------!
k,1,
k,2,inner_rad,0,0
k,3,outer_rad,0,0
k,4,outer_rad,(h_pump-h_ring)/2,0
k,5,outer_rad_ring,(h_pump-h_ring)/2,0
k,6,outer_rad_ring,(h_pump-h_ring)/2+h_ring,0
k,7,outer_rad,(h_pump-h_ring)/2+h_ring,0
k,8,outer_rad,h_pump,0
k,9,inner_rad,h_pump,0
k,10,0,h_pump,0
! keypoints for beam elements
k,11,0,-el_size,0
k,12,0,h_pump+5,0
k,13,0,h_pump+l_higher,0
a,2,3,4,5,6,7,8,9
l,1,11
l,10,13
! Riser for beam elements
ET,1,plane182
MP,EX,1,2.1e11
MP,PRXY,1,.3
MP,DENS,1,7800
MP,DAMP,1,.03
ALLSEL
lesize,all,el_size
amesh,all
el_size = (outer_rad-inner_rad) ! # of elements on the smallest line
ET,2,solid186
vrotat,all,,,,,,1,10
extopt,aclear,1 !to clear the original source area after sweep
vsweep,all,1
nummrg,all
! Riser for beam elements
ET,3,beam188
SECTYPE,1,beam,ctube
SECDATA,inner_rad,outer_rad,10
SECNUM,1
MP, EX, 3, 2.1e11
MP, PRXY, 3, 0.3
MP, DENS,3,7800
MP, DAMP, 3, 0.03 !Material damping 0.03
ALLSEL,ALL,ALL
lsel,s,loc,y,-el_size,0-0.001
lsel,a,loc,y,h_pump+0.001,1000
TYPE,3
LESIZE,ALL,5
LMESH,ALL
nsel,s,loc,x,0
nsel,r,loc,z,0
nsel,r,loc,y,0
!get the node number at the bottom of the pump
*get,node7,node,0,num,max
nsel,all
nsel,s,loc,x,0
nsel,r,loc,z,0
nsel,r,loc,y,h_pump
!get the node number at the top of the pump
*get,node6,node,0,num,max
nsel,all
!----------------------------
! making rigid surfaces on top and bottom
nsel,s,loc,y,h_pump
!nsel,u,node,,node6
cerig,node6,all,all
nsel,all
nsel,s,loc,y,0
!nsel,u,node,,node7
cerig,node7,all,all
nsel,all
!--------------------
!------------Apply rigid body boundary conditions
nsel,all
nsel,s,loc,x,outer_rad_ring
nsel,r,loc,y,(h_pump+h_ring)/2
d,all,ux,0
d,all,uy,0
d,all,uz,0
nsel,all
nsel,s,loc,x,-outer_rad_ring
nsel,r,loc,y,(h_pump+h_ring)/2
d,all,uy,0
d,all,uz,0
nsel,all
nsel,s,loc,x,-outer_rad_ring
nsel,r,loc,y,(h_pump-h_ring)/2
d,all,uz,0
nsel,all
!-----------------------
*dim,forcex,table,4,1
forcex(1,1)=6977,-9620,10280,-7321
forcex(1,0)=1,2,3,4
forcex(0,1)=1
!------------------------
tm_start = 1
tm_end= 4
tm_incr=1
IRLF,1 !inertia relief is active
/solu
ANTYPE,0
*do,tm,tm_start,tm_end,tm_incr
Time,tm
F,node6,Fx,forcex(tm,1)
nsel,all
solve
lswrite
tm=tm+1
*enddo
I have a simple solid model which is statically loaded on one node on top of the structure, subjected to several load steps. The (nodal) loading was obtained using (a much longer structure) LS-Dyna. I would like to obtain the stresses on the Ansys model. So the Ansys model is only a small part of the actual problem, as a result there are no actual constraints on this small part. I am using Inertia Relief.
(Background: I am going to calculate the fatigue on stress concentration points of a pump which is located on a very long riser. LS Dyna calculates the nodal forces, displacements of the riser which is subjected to flow under water. In the Ls dyna model the geometric details are not given. I now model a pump in Ansys, which might be located on this riser, and subjected to the section forces calculated by LS Dyna.)
My question is how to understand if the results are correct? I would like to know with the inertia relief on, am I supposed to see deformation?
Regards,
Bilim
finish
/uis,msgpop,3 ! only show error messages
/clear
/FILNAM,riser
/PREP7
!----------variables--------!
h_pump = 5, ! height of the pump
h_ring = 1,
inner_rad = .3,
outer_rad = .5,
outer_rad_ring = 1,
th_riser=outer_rad-inner_rad,
el_size = (outer_rad-inner_rad) ! # of elements on the smallest line
!------location of the pump
l_riser = 1000 !length of the riser
l_higher=.2 !from the top (sea surface)
l_lower=970 !from the bottom (ground)
!---------------------------!
k,1,
k,2,inner_rad,0,0
k,3,outer_rad,0,0
k,4,outer_rad,(h_pump-h_ring)/2,0
k,5,outer_rad_ring,(h_pump-h_ring)/2,0
k,6,outer_rad_ring,(h_pump-h_ring)/2+h_ring,0
k,7,outer_rad,(h_pump-h_ring)/2+h_ring,0
k,8,outer_rad,h_pump,0
k,9,inner_rad,h_pump,0
k,10,0,h_pump,0
! keypoints for beam elements
k,11,0,-el_size,0
k,12,0,h_pump+5,0
k,13,0,h_pump+l_higher,0
a,2,3,4,5,6,7,8,9
l,1,11
l,10,13
! Riser for beam elements
ET,1,plane182
MP,EX,1,2.1e11
MP,PRXY,1,.3
MP,DENS,1,7800
MP,DAMP,1,.03
ALLSEL
lesize,all,el_size
amesh,all
el_size = (outer_rad-inner_rad) ! # of elements on the smallest line
ET,2,solid186
vrotat,all,,,,,,1,10
extopt,aclear,1 !to clear the original source area after sweep
vsweep,all,1
nummrg,all
! Riser for beam elements
ET,3,beam188
SECTYPE,1,beam,ctube
SECDATA,inner_rad,outer_rad,10
SECNUM,1
MP, EX, 3, 2.1e11
MP, PRXY, 3, 0.3
MP, DENS,3,7800
MP, DAMP, 3, 0.03 !Material damping 0.03
ALLSEL,ALL,ALL
lsel,s,loc,y,-el_size,0-0.001
lsel,a,loc,y,h_pump+0.001,1000
TYPE,3
LESIZE,ALL,5
LMESH,ALL
nsel,s,loc,x,0
nsel,r,loc,z,0
nsel,r,loc,y,0
!get the node number at the bottom of the pump
*get,node7,node,0,num,max
nsel,all
nsel,s,loc,x,0
nsel,r,loc,z,0
nsel,r,loc,y,h_pump
!get the node number at the top of the pump
*get,node6,node,0,num,max
nsel,all
!----------------------------
! making rigid surfaces on top and bottom
nsel,s,loc,y,h_pump
!nsel,u,node,,node6
cerig,node6,all,all
nsel,all
nsel,s,loc,y,0
!nsel,u,node,,node7
cerig,node7,all,all
nsel,all
!--------------------
!------------Apply rigid body boundary conditions
nsel,all
nsel,s,loc,x,outer_rad_ring
nsel,r,loc,y,(h_pump+h_ring)/2
d,all,ux,0
d,all,uy,0
d,all,uz,0
nsel,all
nsel,s,loc,x,-outer_rad_ring
nsel,r,loc,y,(h_pump+h_ring)/2
d,all,uy,0
d,all,uz,0
nsel,all
nsel,s,loc,x,-outer_rad_ring
nsel,r,loc,y,(h_pump-h_ring)/2
d,all,uz,0
nsel,all
!-----------------------
*dim,forcex,table,4,1
forcex(1,1)=6977,-9620,10280,-7321
forcex(1,0)=1,2,3,4
forcex(0,1)=1
!------------------------
tm_start = 1
tm_end= 4
tm_incr=1
IRLF,1 !inertia relief is active
/solu
ANTYPE,0
*do,tm,tm_start,tm_end,tm_incr
Time,tm
F,node6,Fx,forcex(tm,1)
nsel,all
solve
lswrite
tm=tm+1
*enddo
