Non-convergence with yield strength and tangent modulus..

[imse]

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

 

[TGS4]

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.

 

[imse]

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

 

[TGS4]

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...