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Non-convergence with yield strength and tangent modulus..

Non-convergence with yield strength and tangent modulus..

Non-convergence with yield strength and tangent modulus..

(OP)
hi,

I am doing a simulation of Submerged arc welding... using decoupled thermo-mechanical analysis...

I obtained the pretty consistent transient temperature distribution (except for the first set of temperature distribution - probably due to the fact that welding begins at the corner of the plate). This part of the analysis uses temperature dependent conductivity and specific heat; constant density (no enthalpy)

Using the transient temperature result from the thermal analysis I attempted the calculation of stress and distortion with Young’s modulus (constant for now), possions ratio and thermal expansion coefficient (constant for now). I was able to perform a complete transient analysis.

But with the introduction of Yield strength and tangent modulus through bilinear plasticity function in material properties, the solution couldn’t converge - even on the first step. i have tried applying of Newton-ralphson (full) and arc step function

I am hoping to get the final distortion after the completion of welding... i am open to using other methods to obtain plastic deformation or distortions...

Could someone please advice!

Thanx
Robin

RE: Non-convergence with yield strength and tangent modulus..

How are you performing your sub-steps for the non-linear structural analysis?  An input file / log file for your solution processor would be helpful.

RE: Non-convergence with yield strength and tangent modulus..

(OP)
Symmetric half of a Weld plate 18"*3"*3/8"; heat input: heat flux 1.05e8; convection from some surfaces for now.... temperature in Kelvin and properties are in SI units



/PREP7  
!*  
ET,1,SOLID70
!*  
!*  
MPTEMP,,,,,,,,  
MPTEMP,1,273.15
MPTEMP,2,373.15
MPTEMP,3,473.15
MPTEMP,4,573.15
MPTEMP,5,673.15
MPTEMP,6,773.15
MPTEMP,7,873.15
MPTEMP,8,973.15
MPTEMP,9,1073.15
MPTEMP,10,1273.15   
MPTEMP,11,1473.15   
MPTEMP,12,1773.15   
MPTEMP,13,2073.15
 
MPDATA,KXX,1,,51.9  
MPDATA,KXX,1,,51.1  
MPDATA,KXX,1,,49
MPDATA,KXX,1,,46
MPDATA,KXX,1,,42.7  
MPDATA,KXX,1,,39.4  
MPDATA,KXX,1,,35.6  
MPDATA,KXX,1,,31.8  
MPDATA,KXX,1,,26
MPDATA,KXX,1,,27.2  
MPDATA,KXX,1,,29.7  
MPDATA,KXX,1,,35
MPDATA,KXX,1,,41.5  


MPTEMP,,,,,,,,  
MPTEMP,1,323.15
MPTEMP,2,373.15
MPTEMP,3,423.15
MPTEMP,4,473.15
MPTEMP,5,523.15
MPTEMP,6,573.15
MPTEMP,7,623.15
MPTEMP,8,673.15
MPTEMP,9,723.15
MPTEMP,10,773.15
MPTEMP,11,823.15
MPTEMP,12,873.15
MPTEMP,13,923.15
MPTEMP,14,973.15
MPTEMP,15,1023.15   
MPTEMP,16,1073.15   
MPTEMP,17,1773.15  
MPDE,C,1
MPDATA,C,1,,486
MPDATA,C,1,,486
MPDATA,C,1,,5519
MPDATA,C,1,,532
MPDATA,C,1,,557
MPDATA,C,1,,574
MPDATA,C,1,,599
MPDATA,C,1,,599
MPDATA,C,1,,662
MPDATA,C,1,,662
MPDATA,C,1,,749
MPDATA,C,1,,749
MPDATA,C,1,,846
MPDATA,C,1,,1432
MPDATA,C,1,,950
MPDATA,C,1,,950
MPDATA,C,1,,950
MPTEMP,,,,,,,,  
MPTEMP,1,0  
MPDATA,DENS,1,,7859


BLOCK,0,.46,0,.0095,0,-.076,
! /VIEW,1,1,1,1   
! /ANG,1  
! /REP,FAST   
wpstyle,0.0095,0.1,-1,1,0.003,0,0,,5
wpof,,0.009500  
wpro,30.000000,,
wpro,-30.000000,,   
wpro,,,30.000000
wpro,,,-30.000000   
wpro,,30.000000,
wpro,,-30.000000,   
wpro,,-30.000000,   
wpro,,-30.000000,   
wpro,,-30.000000,   
wpstyle,0.004,0.1,-1,1,0.004,0,0,,5
wpof,0.005000   
CYLIND,.0050, ,0,.001,0,180,
WPSTYLE,,,,,,,,0

FLST,2,2,6,ORDE,2   
FITEM,2,1   
FITEM,2,-2  
VGLUE,P51X  
ESIZE,0.01,0,   
MSHKEY,0
MSHAPE,1,3d
FLST,5,2,6,ORDE,2   
FITEM,5,3   
FITEM,5,-4  
CM,_Y,VOLU  
VSEL, , , ,P51X
CM,_Y1,VOLU
CHKMSH,'VOLU'   
CMSEL,S,_Y  
!*  
VMESH,_Y1   
!*  
CMDELE,_Y   
CMDELE,_Y1  
CMDELE,_Y2  

ALLSEL, ALL
TUNIF, 294

!**************TRANSIENT TEMP ANALYSIS*******************

  
FLST,2,2,6,ORDE,2   
FITEM,2,3   
FITEM,2,-4  
VCLEAR,P51X
FLST,2,2,6,ORDE,2   
FITEM,2,3   
FITEM,2,-4  
VCLEAR,P51X
   
FLST,3,1,6,ORDE,1   
FITEM,3,3   
VGEN,42,P51X, , ,.01, , , ,0

FLST,2,43,6,ORDE,2  
FITEM,2,1   
FITEM,2,-43
VGLUE,P51X  
MSHKEY,0
MSHAPE,1,3d
FLST,5,43,6,ORDE,3  
FITEM,5,1   
FITEM,5,44  
FITEM,5,-85
CM,_Y,VOLU  
VSEL, , , ,P51X
CM,_Y1,VOLU
CHKMSH,'VOLU'   
CMSEL,S,_Y  
!*  
VMESH,_Y1   
!*  
CMDELE,_Y   
CMDELE,_Y1  
CMDELE,_Y2  
!*  
FINISH  
/SOL
!*  
ANTYPE,4
!*  
TRNOPT,FULL
LUMPM,0
!*  
FLST,2,2,5,ORDE,2   
FITEM,2,1   
FITEM,2,6   
/GO
!*  
SFA,P51X,1,CONV,25,294  
ALLSEL,ALL  
FLST,2,1540,1,ORDE,2
FITEM,2,1   
FITEM,2,-1540   
IC,P51X,TEMP,294,   
  
FLST,2,1,5,ORDE,1   
FITEM,2,218
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
OUTRES,ALL,ALL,
!*  
TIME,1.25   
AUTOTS,-1   
DELTIM,1.25,0.001, ,1
KBC,0   
!*  
TSRES,ERASE
LSWRITE,1,  
FLST,2,1,5,ORDE,1   
FITEM,2,218
SFADELE,P51X,1,HFLUX
FLST,2,1,5,ORDE,1   
FITEM,2,2   
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,2.5
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,2,  
FLST,2,1,5,ORDE,1   
FITEM,2,2   
SFADELE,P51X,1,HFLUX




FLST,2,1,5,ORDE,1   
FITEM,2,221   
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,3.75
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,3,  
FLST,2,1,5,ORDE,1   
FITEM,2,221   
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,225   
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,5
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,4,  
FLST,2,1,5,ORDE,1   
FITEM,2,225   
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,229   
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,6.25
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,5,  
FLST,2,1,5,ORDE,1   
FITEM,2,229   
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,233   
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,7.5
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,6,  
FLST,2,1,5,ORDE,1   
FITEM,2,233   
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,237   
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,8.75
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,7,  
FLST,2,1,5,ORDE,1   
FITEM,2,237   
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,241   
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,10
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,8,  
FLST,2,1,5,ORDE,1   
FITEM,2,241   
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,245  
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,11.25
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,9,  
FLST,2,1,5,ORDE,1   
FITEM,2,245   
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,249   
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,12.5
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,10,  
FLST,2,1,5,ORDE,1   
FITEM,2,249   
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,253
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,13.75
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,11,  
FLST,2,1,5,ORDE,1   
FITEM,2,253  
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,257   
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,15
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,12,  
FLST,2,1,5,ORDE,1   
FITEM,2,257   
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,261
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,16.25
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,13,  
FLST,2,1,5,ORDE,1   
FITEM,2,261  
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,265   
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,17.5
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,14,  
FLST,2,1,5,ORDE,1   
FITEM,2,265   
SFADELE,P51X,1,HFLUX



FLST,2,1,5,ORDE,1   
FITEM,2,269
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,18.75
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,15,  
FLST,2,1,5,ORDE,1   
FITEM,2,269  
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,273   
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,20
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,16,  
FLST,2,1,5,ORDE,1   
FITEM,2,273   
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,277
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,21.25
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,17,  
FLST,2,1,5,ORDE,1   
FITEM,2,277
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,281   
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,22.5
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,18,  
FLST,2,1,5,ORDE,1   
FITEM,2,281   
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,285
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,23.75
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,19,  
FLST,2,1,5,ORDE,1   
FITEM,2,285
SFADELE,P51X,1,HFLUX


FLST,2,1,5,ORDE,1   
FITEM,2,289   
/GO
!*  
SFA,P51X,1,HFLUX,1.05e8  
!*  
TIME,25
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,20,  
FLST,2,1,5,ORDE,1   
FITEM,2,289   
SFADELE,P51X,1,HFLUX

TIME,150
AUTOTS,-1   
DELTIM,1.25,0.001, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,21,


!**************TRANSIENT Stress ANALYSIS*******************

/PREP7  
ETCHG,TTS   
FINISH  
/SOL
LSCLEAR,ALL

MPTEMP,,,,,,,,  
MPTEMP,1,0  
MPDATA,EX,1,,2.1e11
MPDATA,PRXY,1,,.3   
MPTEMP,,,,,,,,  
MPTEMP,1,0  
UIMP,1,REFT,,,  
MPDATA,ALPX,1,,11.1e-6

TBDE,BKIN,1
TB,BISO,1,1,2,  
TBTEMP,0
TBDATA,,250e6,4.8e9,,,,


!*  
ANTYPE,4
!*  
TRNOPT,FULL
LUMPM,0
ARCLEN,ON   
DA,     382,SYMM
  
 
ALLSEL,ALL  

TIME,1.25   
AUTOTS,-1   
DELTIM,1.25,.25, ,1
KBC,0   
!*  
TSRES,ERASE
LDREAD,TEMP,,,1.25, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
LSWRITE,1,  
LDREAD,TEMP,,,2.5, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '
!*  
TIME,2.5
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,2,  
LDREAD,TEMP,,,3.75, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,3.75
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,3,  

LDREAD,TEMP,,,5, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,5
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,4,  

LDREAD,TEMP,,,6.25, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,6.25
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,5,  

LDREAD,TEMP,,,7.5, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,7.5
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,6,  

LDREAD,TEMP,,,8.75, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,8.75
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,7,  

LDREAD,TEMP,,,10, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,10
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,8,

LDREAD,TEMP,,,11.25, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,11.25
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,9,  


LDREAD,TEMP,,,12.5, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,12.5
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,10,  


LDREAD,TEMP,,,13.75, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,13.75
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,11,  


LDREAD,TEMP,,,15, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,15
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,12,

LDREAD,TEMP,,,16.25, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,16.25
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,13,

LDREAD,TEMP,,,17.5, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,17.5
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,14,  


LDREAD,TEMP,,,18.75, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,18.75
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,15,  


LDREAD,TEMP,,,20, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,20
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,16,  


LDREAD,TEMP,,,21.25, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,21.25
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,17,

LDREAD,TEMP,,,22.5, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,22.5
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,18,  


LDREAD,TEMP,,,23.75, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,23.75
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,19,  


LDREAD,TEMP,,,25, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,25
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,20,


LDREAD,TEMP,,,25, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,25
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,20,
   


ARCLEN,OFF

LDREAD,TEMP,,,150, ,'TRIAL_KELVIN_heatflux_1.05e8','rth',' '   
!*  
TIME,150
AUTOTS,-1   
DELTIM,1.25,0.25, ,1   
KBC,0   
!*  
TSRES,ERASE
LSWRITE,21,


thank you
Robin

RE: Non-convergence with yield strength and tangent modulus..

Is it just me or is this missing an lssolve command.  Something to try - try performing just one analysis with only one structural load step and see if you can get convergence on the structural end of things.

Also, I would not use the arclen method - it's really mostly appropriate for non-linear buckling problems.  I would use auto time-stepping and set a much smaller minimum time step for the structural analysis.  In fact, have you tried the analysis with solcontrol,on?

Give these a try...

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