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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sohrab posted this 01 February 2019

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

sathya posted this 01 February 2019

What was the error/warning you faced?

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