simplified dislocation kinetics: dropped relativistic correction of velocity, since the infinite attack frequency already sets a limit for the velocity; dropped second; also dropped the correction term for backward jumps, since it was probably not meaningful
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Christoph Kords
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5ca6b89983
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cee90bbdb3
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@ -304,7 +304,6 @@ viscosity 1e-4 # viscosity for dislocation gli
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p 1 # exponent for thermal barrier profile
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q 1 # exponent for thermal barrier profile
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attackFrequency 50e9 # attack frequency in Hz
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maximumVelocity 3600 # maximum allowed velocity
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surfaceTransmissivity 1.0 # transmissivity of free surfaces for dislocation flux
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grainboundaryTransmissivity 0.0 # transmissivity of grain boundaries for dislocation flux (grain bundaries are identified as interfaces with different textures on both sides); if not set or set to negative number, the subroutine automatically determines the transmissivity at the grain boundary
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interaction_SlipSlip 0 0 0.625 0.07 0.137 0.122 # Dislocation interaction coefficient
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@ -121,7 +121,6 @@ constitutive_nonlocal_p, & ! parameter
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constitutive_nonlocal_q, & ! parameter for kinetic law (Kocks,Argon,Ashby)
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constitutive_nonlocal_viscosity, & ! viscosity for dislocation glide in Pa s
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constitutive_nonlocal_fattack, & ! attack frequency in Hz
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constitutive_nonlocal_vmax, & ! maximum allowed velocity
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constitutive_nonlocal_rhoSglScatter, & ! standard deviation of scatter in initial dislocation density
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constitutive_nonlocal_surfaceTransmissivity, & ! transmissivity at free surface
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constitutive_nonlocal_grainboundaryTransmissivity, & ! transmissivity at grain boundary (identified by different texture)
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@ -324,7 +323,6 @@ allocate(constitutive_nonlocal_p(maxNinstance))
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allocate(constitutive_nonlocal_q(maxNinstance))
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allocate(constitutive_nonlocal_viscosity(maxNinstance))
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allocate(constitutive_nonlocal_fattack(maxNinstance))
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allocate(constitutive_nonlocal_vmax(maxNinstance))
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allocate(constitutive_nonlocal_rhoSglScatter(maxNinstance))
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allocate(constitutive_nonlocal_rhoSglRandom(maxNinstance))
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allocate(constitutive_nonlocal_rhoSglRandomBinning(maxNinstance))
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@ -357,7 +355,6 @@ constitutive_nonlocal_p = 1.0_pReal
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constitutive_nonlocal_q = 1.0_pReal
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constitutive_nonlocal_viscosity = 0.0_pReal
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constitutive_nonlocal_fattack = 0.0_pReal
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constitutive_nonlocal_vmax = 0.0_pReal
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constitutive_nonlocal_rhoSglScatter = 0.0_pReal
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constitutive_nonlocal_rhoSglRandom = 0.0_pReal
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constitutive_nonlocal_rhoSglRandomBinning = 1.0_pReal
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@ -541,8 +538,6 @@ do
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constitutive_nonlocal_viscosity(i) = IO_floatValue(line,positions,2_pInt)
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case('attackfrequency','fattack')
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constitutive_nonlocal_fattack(i) = IO_floatValue(line,positions,2_pInt)
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case('maximumvelocity','vmax')
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constitutive_nonlocal_vmax(i) = IO_floatValue(line,positions,2_pInt)
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case('rhosglscatter')
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constitutive_nonlocal_rhoSglScatter(i) = IO_floatValue(line,positions,2_pInt)
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case('rhosglrandom')
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@ -661,8 +656,6 @@ enddo
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//constitutive_nonlocal_label//')')
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if (constitutive_nonlocal_fattack(i) <= 0.0_pReal) call IO_error(211_pInt,ext_msg='attackFrequency (' &
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//constitutive_nonlocal_label//')')
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if (constitutive_nonlocal_vmax(i) <= 0.0_pReal) call IO_error(211_pInt,ext_msg='maximumVelocity (' &
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//constitutive_nonlocal_label//')')
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if (constitutive_nonlocal_rhoSglScatter(i) < 0.0_pReal) call IO_error(211_pInt,ext_msg='rhoSglScatter (' &
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//constitutive_nonlocal_label//')')
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if (constitutive_nonlocal_rhoSglRandom(i) < 0.0_pReal) call IO_error(211_pInt,ext_msg='rhoSglRandom (' &
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@ -1592,30 +1585,15 @@ if (Temperature > 0.0_pReal) then
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!* Mean velocity results from waiting time at peierls barriers and solid solution obstacles with respective meanfreepath of
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!* free flight at glide velocity in between. Backward jumps at low stresses are considered only at peierls barriers,
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!* since those have the smallest activation volume, thus are decisive.
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v(s) = 1.0_pReal / (tPeierls / meanfreepath_P + tSolidSolution / meanfreepath_S + 1.0_pReal / vViscous) &
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* (1.0_pReal - exp(-tauEff(s) * activationVolume_P / (kB * Temperature)))
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if (present(dv_dtau)) then
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dv_dtau(s) = 1.0_pReal / (tPeierls / meanfreepath_P + tSolidSolution / meanfreepath_S + 1.0_pReal / vViscous) &
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* (v(s) * ( dtPeierls_dtau / meanfreepath_P + dtSolidSolution_dtau / meanfreepath_S &
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+ 1.0_pReal / (mobility * tauEff(s)*tauEff(s))) &
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+ activationVolume_P / (kB * Temperature) * exp(-tauEff(s) * activationVolume_P / (kB * Temperature)))
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endif
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!* relativistic correction
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if (present(dv_dtau)) then
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dv_dtau(s) = dv_dtau(s) * exp( -v(s) / constitutive_nonlocal_vmax(instance))
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endif
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v(s) = constitutive_nonlocal_vmax(instance) * (1.0_pReal - exp( -v(s) / constitutive_nonlocal_vmax(instance)))
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!* free flight at glide velocity in between.
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!* adopt sign from resolved stress
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v(s) = sign(v(s),tau(s))
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v(s) = sign(1.0_pReal,tau(s)) / (tPeierls / meanfreepath_P + tSolidSolution / meanfreepath_S + 1.0_pReal / vViscous)
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if (present(dv_dtau)) then
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dv_dtau(s) = v(s) * v(s) * (dtPeierls_dtau / meanfreepath_P + dtSolidSolution_dtau / meanfreepath_S &
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+ 1.0_pReal / (mobility * tauEff(s)*tauEff(s)))
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endif
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endif
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enddo
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