Time varying load step

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  • Last Post 01 February 2019
sohrab posted this 30 January 2019

Hi everyone,

I want to make a loading such as following in my XFEM code using CBC loading

as can be seen R varies from -1 to 0 . prior over load is 230Mpa (R=-1) and then reduces to 115 Mpa (R=0).

230Mpa loading should be 10 cycles and after that 115Mpa pressure applies to model .

 

I used the following but it did not work. 

 

/solu
antype,0
*DIM,PRESSURE,TABLE,2,1
*DIM,stressratio,TABLE,2,1

PRESSURE(1,1)=-230,-115
PRESSURE(1,0)=0,1
PRESSURE(0,1)=1
stressratio(1,1)=-1,0
stressratio(1,0)=0,1
stressratio(0,1)=1

TM_START=1E-6               ! Starting time (must be > 0)
TM_END=5             ! Ending time of the transient
TM_INCR=0.1              ! Time increment
outres,all, all

! CINT calculations
CINT, NEW, 1
CINT, TYPE, SIFS
CINT, CXFE, crktipelem
CINT, NCON, 8
CINT, NORM, 0, 2
CINT, PLOT, 1, 1
! CGROW calculations
cgrow, new, 1
cgrow, cid, 1
cgrow, method, xfem
cgrow, fcoption, mtab, 2
CGROW, STOP, CEMX, 18   !CRK CONTROL
! Fatigue-related data
CGROW, FCG, METH, CBC     ! life-cycle method
CGROW,FCG,DN,10
 

kbc, 1  ! loads are stepped for fatigue analysis

*DO,TM,TM_START,TM_END,TM_INCR    ! Do for TM from TM_START to TM_END in
   
   TIME,TM                  ! Time value

CGROW, FCG, SRAT,stressratio(TM)     ! stress-ratio---R  


   nsel,s,loc, Y, 50
sf, all, pres, PRESSURE(TM)
allsel
nsel,s,loc, Y, 0
sf, all, pres, PRESSURE(TM)
allsel
! B.C
nsel,s,loc, Y, 25.05
nsel,r,loc, x, 50
d, all, uy,0.0
d, all, uX,0.0
allsel

nsel,s,loc, Y, 25.05
nsel,r,loc, x, 0
d, all, uy,0.0
d, all, uX,0.0
allsel

   SOLVE                    ! Initiate solution calculations
*ENDDO

 


finish

 

 

anybody have experience in this regard?

I appreciate your comments and helps in advance

 

 

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sathya posted this 01 February 2019

What was the error/warning you faced?

sohrab posted this 01 February 2019

it does not accept change of stress ratio at each step. it says internal input error.

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