My ANSYS LS-DYNA 9.0 full restart analyses seems to ignore the EDRD,D2R command.
Is this a known error in deformable-to-rigid switching? Is there a workaround?


Defect 34412 was filed and corrected in the UP20050520 build of ANSYS LS-DYNA 10.0.
Please see the example below that demonstrates the error in releases prior to 10.0
and a workaround (editing the .K file to add the necessary *DEFORMABLE_TO_RIGID
command). Small restarts were not effected by this error, which is only in full restarts.
The input file below is also attached to this solution record.


! = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

fini
/clear

/title, ANSYS LS-DYNA 9.0 Full Restart with Rigid-to-Deformable Switching

/filnam,file_1

/plopts,info,1
/pnum,node,1
/pnum,elem,1
/view,,1,2,3

/prep7
et,1,SHELL163,10
r,1,,5,0.10
edint,5,4
mp,ex,1,30.0e6
mp,nuxy,1,0.30
mp,dens,1,0.00074
tb,biso,1
tbdata,1,60.0e3
tbdata,2,30.0e4
edmp,hgls,1,5

et,2,SOLID164
r,2
mp,ex,2,30.0e6
mp,nuxy,2,0.30
mp,dens,2,0.00074
tb,biso,2
tbdata,1,60.0e3
tbdata,2,30.0e4
edmp,hgls,2,5

mat,1
type,1
real,1
n,1, 0.0, 0.0, 0.0
n,2, 1.0, 0.0, 0.0
ngen,4,2,1,2,1,0.0,1.0,0.0
e,1,2,4,3
e,3,4,6,5
e,5,6,8,7
cm,nshell,node
cm,eshell,elem
nsel,none
esel,none

mat,2
type,2
real,2
block,0,1,0,4,-2,-1
esize,0.5
vmesh,1
cm,nsolid,node
cm,esolid,elem
nsel,all
esel,all
eplot

edpart,create
eddamp,all,,0.02
eddamp,1,,1.0e-4
eddamp,2,,1.0e-4
fini

/solu
cmsel,s,nshell
nsel,r,loc,y,0.0
cm,nbase,node
esln
cm,ebase,elem

cmsel,s,nshell
nsel,r,loc,y,3.0
cm,ntip,node
esln
cm,etip,elem

nsel,s,loc,y,0
nsel,r,loc,z,-1
cm,npivot,node
nsel,s,loc,y,4
nsel,r,loc,z,-2
cm,npull,node
nsel,r,loc,x,1
cm,nrigid,node ! need single node component for load application when rigid ...

esel,all
nsel,all
eplot

d,nbase,ux,0.0,,,,uy,uz,rotx,roty,rotz

d,npivot,ux,0.0,,,,uy,uz

*dim,etime,,3
*dim,zdisp,,3
*dim,ydisp,,3
etime(1)=0.0,0.05,0.101
zdisp(1)=0.0,0.50,0.50
ydisp(1)=0.0,0.25,0.25
edload,add,uz,,ntip,etime(1),zdisp(1)
edload,add,uy,,npull,etime(1),ydisp(1)

time,0.100
edrst,10
edhtime,100
edhist,ntip
edhist,nbase
edhist,npivot
edhist,npull
edhist,ebase
edenergy,1,1,1,1
edout,glstat
edout,matsum
edout,spcforc
edopt,add,,both

edrd,d2r ! needed to initialize bodies ...

! EDRD Command Notes:
!
! This command is valid in a new explicit dynamic analysis or in a restart.
! It is only possible to switch parts (D2R or R2D) in a restart if part
! switching is first activated in the original analysis. If part switching
! is not required in the original analysis but will be used in the restart,
! you must issue EDRD,D2R with no further arguments in the original analysis.

save
solve
save
fini

/post1
file,file_1,rst
set,last
/edge,,1
/dscale,,1
plnsol,u,z,2
/wait,2
fini

/post26
numvar,30
file,file_1,his
nsol,2,8,u,z,nshltip
ntrack=node(1,4,-2)
nsol,3,ntrack,u,y,nsoltip
prvar,2,3
plvar,2,3
/wait,2
fini

! = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

/solu
edstart,3,,,d3dump01 ! full restart - Jobname changed automatically ...

edis ! stress initialization for all parts ...

edrd,d2r,2 ! switch solid deformable block to rigid body ...

ddele,npivot,all ! cannot have conflicting constraints for rigid body ...

*dim,etime2,,3
*dim,zdisp2,,3
*dim,ydisp2,,3
etime2(1)=0.10,0.15,0.201
zdisp2(1)=0.50,1.00,0.75
ydisp2(1)=0.25,0.50,0.50
edload,add,uz,,ntip,etime2(1),zdisp2(1)

!!! edload,add,uy,,npull,etime2(1),ydisp2(1) ! this will not work, since rigid now ...
!!!
!!! *** Warning too many presribed nodal displacements
!!! found during rigid body switching
!!! rigid body part ID 2 limit=1.
!!! Check output to ensure expected behavior.
!!! Nodal list:
!!! Node ID 9
!!! Node ID 18
!!! Node ID 19

edload,dele,uy,,npull,etime(1),ydisp(1) ! first remove old conflicting load ...
edload,add,uy,,nrigid,etime2(1),ydisp2(1) ! component consists of a single node ...

time,0.200
edrst,20
edhtime,200
edhist,ntip
edhist,nbase
edhist,npivot
edhist,npull
edhist,ebase
edenergy,1,1,1,1
edout,glstat
/sys,copy glstat old_glstat
edout,matsum
/sys,copy matsum old_matsum
edout,spcforc
/sys,copy spcforc old_spcforc
edopt,add,,both

save
!!! solve ! edit .K file directly to provide workaround to error ...
!!! save
!!! fini

edwrite,both,,k ! write out .K file and add deformable-to-rigid switching command ...

/eof

! = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

The following commands are needed for this model to add deformable-to-rigid
switching in a full restart analysis in ANSYS LS-DYNA 9.0:

*DEFORMABLE_TO_RIGID
2

Then run the LS-DYNA 970 executable from the command line:

"C:Program FilesAnsys Incv90ANSYSbinintells970.exe" i=file_2.k r=d3dump01 pr=DYNA

where:

file_2.k = .K file created by EDWRITE to which the *DEFORMABLE_TO_RIGID command is added

d3dump01 = restart file from where you want to resume the analysis

DYNA = product variable for ANSYS LS-DYNA ("ANSYSDS" for Mechanical/LS-DYNA,
"ANE3FLDS" for Multiphysics/LS-DYNA, etc. - see Licensing Guide)

See Section 5.7.2 "Method B" in the ANSYS LS-DYNA User's Guide for Release 9.0
for more examples on editing the .K file and submitting the job ...

! = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

! After the job finishes, issue the following:

fini

/filnam,file_2
resume

/post1
file,file_2,rst
set,last
/edge,,1
/dscale,,1
plnsol,u,z,2
/wait,2
fini

/post26
numvar,30
file,file_2,his
nsol,2,8,u,z,nshltip
ntrack=node(1,4,-2)
nsol,3,ntrack,u,y,nsoltip
prvar,2,3
plvar,2,3

/eof

! = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =



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