* now able to introduce some scatter in the initial single dislocation density (only for nonlocal model!) ; setting the parameter "rhoSglScatter" to a positive value generates a gauss distribution for the dislocation density with standard deviation equal to "rhoSglScatter"

* dislocation stress calculation is only done for nonlocal constitution ("/nonlocal/" keyword is present in material.config)
This commit is contained in:
Christoph Kords 2011-02-04 15:41:32 +00:00
parent 6511b4b5a2
commit faba13f7fd
4 changed files with 145 additions and 78 deletions

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@ -1227,6 +1227,8 @@ endfunction
msg = 'Non-positive wall depth' msg = 'Non-positive wall depth'
case (237) case (237)
msg = 'Non-positive obstacle strength' msg = 'Non-positive obstacle strength'
case (238)
msg = 'Negative scatter for dislocation density'
case (240) case (240)
msg = 'Non-positive Taylor factor' msg = 'Non-positive Taylor factor'
case (241) case (241)

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@ -62,7 +62,8 @@ real(pReal), dimension(:), allocatable :: constitutive_nonlocal_
constitutive_nonlocal_d0, & ! wall depth as multiple of b constitutive_nonlocal_d0, & ! wall depth as multiple of b
constitutive_nonlocal_tauObs, & ! obstacle strength in Pa constitutive_nonlocal_tauObs, & ! obstacle strength in Pa
constitutive_nonlocal_fattack, & ! attack frequency in Hz constitutive_nonlocal_fattack, & ! attack frequency in Hz
constitutive_nonlocal_vs ! maximum dislocation velocity = velocity of sound constitutive_nonlocal_vs, & ! maximum dislocation velocity = velocity of sound
constitutive_nonlocal_rhoSglScatter ! standard deviation of scatter in initial dislocation density
real(pReal), dimension(:,:,:), allocatable :: constitutive_nonlocal_Cslip_66 ! elasticity matrix in Mandel notation for each instance real(pReal), dimension(:,:,:), allocatable :: constitutive_nonlocal_Cslip_66 ! elasticity matrix in Mandel notation for each instance
real(pReal), dimension(:,:,:,:,:), allocatable :: constitutive_nonlocal_Cslip_3333 ! elasticity matrix for each instance real(pReal), dimension(:,:,:,:,:), allocatable :: constitutive_nonlocal_Cslip_3333 ! elasticity matrix for each instance
real(pReal), dimension(:,:), allocatable :: constitutive_nonlocal_rhoSglEdgePos0, & ! initial edge_pos dislocation density per slip system for each family and instance real(pReal), dimension(:,:), allocatable :: constitutive_nonlocal_rhoSglEdgePos0, & ! initial edge_pos dislocation density per slip system for each family and instance
@ -222,6 +223,7 @@ allocate(constitutive_nonlocal_d0(maxNinstance))
allocate(constitutive_nonlocal_tauObs(maxNinstance)) allocate(constitutive_nonlocal_tauObs(maxNinstance))
allocate(constitutive_nonlocal_vs(maxNinstance)) allocate(constitutive_nonlocal_vs(maxNinstance))
allocate(constitutive_nonlocal_fattack(maxNinstance)) allocate(constitutive_nonlocal_fattack(maxNinstance))
allocate(constitutive_nonlocal_rhoSglScatter(maxNinstance))
constitutive_nonlocal_CoverA = 0.0_pReal constitutive_nonlocal_CoverA = 0.0_pReal
constitutive_nonlocal_C11 = 0.0_pReal constitutive_nonlocal_C11 = 0.0_pReal
constitutive_nonlocal_C12 = 0.0_pReal constitutive_nonlocal_C12 = 0.0_pReal
@ -241,6 +243,7 @@ constitutive_nonlocal_d0 = 0.0_pReal
constitutive_nonlocal_tauObs = 0.0_pReal constitutive_nonlocal_tauObs = 0.0_pReal
constitutive_nonlocal_vs = 0.0_pReal constitutive_nonlocal_vs = 0.0_pReal
constitutive_nonlocal_fattack = 0.0_pReal constitutive_nonlocal_fattack = 0.0_pReal
constitutive_nonlocal_rhoSglScatter = 0.0_pReal
allocate(constitutive_nonlocal_rhoSglEdgePos0(lattice_maxNslipFamily, maxNinstance)) allocate(constitutive_nonlocal_rhoSglEdgePos0(lattice_maxNslipFamily, maxNinstance))
allocate(constitutive_nonlocal_rhoSglEdgeNeg0(lattice_maxNslipFamily, maxNinstance)) allocate(constitutive_nonlocal_rhoSglEdgeNeg0(lattice_maxNslipFamily, maxNinstance))
@ -349,6 +352,8 @@ do
constitutive_nonlocal_vs(i) = IO_floatValue(line,positions,2) constitutive_nonlocal_vs(i) = IO_floatValue(line,positions,2)
case('fattack') case('fattack')
constitutive_nonlocal_fattack(i) = IO_floatValue(line,positions,2) constitutive_nonlocal_fattack(i) = IO_floatValue(line,positions,2)
case('rhosglscatter')
constitutive_nonlocal_rhoSglScatter(i) = IO_floatValue(line,positions,2)
end select end select
endif endif
enddo enddo
@ -392,6 +397,7 @@ enddo
if (constitutive_nonlocal_tauObs(i) <= 0.0_pReal) call IO_error(237) if (constitutive_nonlocal_tauObs(i) <= 0.0_pReal) call IO_error(237)
if (constitutive_nonlocal_vs(i) <= 0.0_pReal) call IO_error(226) if (constitutive_nonlocal_vs(i) <= 0.0_pReal) call IO_error(226)
if (constitutive_nonlocal_fattack(i) <= 0.0_pReal) call IO_error(235) if (constitutive_nonlocal_fattack(i) <= 0.0_pReal) call IO_error(235)
if (constitutive_nonlocal_rhoSglScatter(i) < 0.0_pReal) call IO_error(238)
!*** determine total number of active slip systems !*** determine total number of active slip systems
@ -629,11 +635,13 @@ endsubroutine
!********************************************************************* !*********************************************************************
!* initial microstructural state (just the "basic" states) * !* initial microstructural state (just the "basic" states) *
!********************************************************************* !*********************************************************************
pure function constitutive_nonlocal_stateInit(myInstance) function constitutive_nonlocal_stateInit(myInstance)
use prec, only: pReal, & use prec, only: pReal, &
pInt pInt
use lattice, only: lattice_maxNslipFamily use lattice, only: lattice_maxNslipFamily
use math, only: math_sampleGaussVar
implicit none implicit none
!*** input variables !*** input variables
@ -661,8 +669,9 @@ integer(pInt) ns, & ! short notation f
f, & ! index of lattice family f, & ! index of lattice family
from, & from, &
upto, & upto, &
s ! index of slip system s, & ! index of slip system
i
real(pReal), dimension(2) :: noise
constitutive_nonlocal_stateInit = 0.0_pReal constitutive_nonlocal_stateInit = 0.0_pReal
ns = constitutive_nonlocal_totalNslip(myInstance) ns = constitutive_nonlocal_totalNslip(myInstance)
@ -670,12 +679,17 @@ ns = constitutive_nonlocal_totalNslip(myInstance)
!*** set the basic state variables !*** set the basic state variables
do f = 1,lattice_maxNslipFamily do f = 1,lattice_maxNslipFamily
from = 1+sum(constitutive_nonlocal_Nslip(1:f-1,myInstance)) from = 1 + sum(constitutive_nonlocal_Nslip(1:f-1,myInstance))
upto = sum(constitutive_nonlocal_Nslip(1:f,myInstance)) upto = sum(constitutive_nonlocal_Nslip(1:f,myInstance))
rhoSglEdgePos(from:upto) = constitutive_nonlocal_rhoSglEdgePos0(f, myInstance) do s = from,upto
rhoSglEdgeNeg(from:upto) = constitutive_nonlocal_rhoSglEdgeNeg0(f, myInstance) do i = 1,2
rhoSglScrewPos(from:upto) = constitutive_nonlocal_rhoSglScrewPos0(f, myInstance) noise(i) = math_sampleGaussVar(0.0_pReal, constitutive_nonlocal_rhoSglScatter(myInstance))
rhoSglScrewNeg(from:upto) = constitutive_nonlocal_rhoSglScrewNeg0(f, myInstance) enddo
rhoSglEdgePos(s) = constitutive_nonlocal_rhoSglEdgePos0(f, myInstance) + noise(1)
rhoSglEdgeNeg(s) = constitutive_nonlocal_rhoSglEdgeNeg0(f, myInstance) + noise(1)
rhoSglScrewPos(s) = constitutive_nonlocal_rhoSglScrewPos0(f, myInstance) + noise(2)
rhoSglScrewNeg(s) = constitutive_nonlocal_rhoSglScrewNeg0(f, myInstance) + noise(2)
enddo
rhoSglEdgePosUsed(from:upto) = 0.0_pReal rhoSglEdgePosUsed(from:upto) = 0.0_pReal
rhoSglEdgeNegUsed(from:upto) = 0.0_pReal rhoSglEdgeNegUsed(from:upto) = 0.0_pReal
rhoSglScrewPosUsed(from:upto) = 0.0_pReal rhoSglScrewPosUsed(from:upto) = 0.0_pReal
@ -905,14 +919,17 @@ forall (s = 1:ns) &
!*** calculate the dislocation stress of the neighboring excess dislocation densities !*** calculate the dislocation stress of the neighboring excess dislocation densities
Tdislocation_v = 0.0_pReal Tdislocation_v = 0.0_pReal
F = math_mul33x33(Fe(:,:,g,ip,el), Fp(:,:,g,ip,el))
invFe = math_inv3x3(Fe(:,:,g,ip,el))
nu = constitutive_nonlocal_nu(myInstance)
forall (s = 1:ns, c = 1:2) & if (.not. phase_localConstitution(material_phase(g,ip,el))) then ! only calculate dislocation stress for nonlocal material
F = math_mul33x33(Fe(:,:,g,ip,el), Fp(:,:,g,ip,el))
invFe = math_inv3x3(Fe(:,:,g,ip,el))
nu = constitutive_nonlocal_nu(myInstance)
forall (s = 1:ns, c = 1:2) &
rhoExcess(c,s) = state(g,ip,el)%p((2*c-2)*ns+s) + abs(state(g,ip,el)%p((2*c+2)*ns+s)) & rhoExcess(c,s) = state(g,ip,el)%p((2*c-2)*ns+s) + abs(state(g,ip,el)%p((2*c+2)*ns+s)) &
- state(g,ip,el)%p((2*c-1)*ns+s) - abs(state(g,ip,el)%p((2*c+3)*ns+s)) - state(g,ip,el)%p((2*c-1)*ns+s) - abs(state(g,ip,el)%p((2*c+3)*ns+s))
do n = 1,6 do n = 1,6
neighboring_el = mesh_ipNeighborhood(1,n,ip,el) neighboring_el = mesh_ipNeighborhood(1,n,ip,el)
neighboring_ip = mesh_ipNeighborhood(2,n,ip,el) neighboring_ip = mesh_ipNeighborhood(2,n,ip,el)
if ( neighboring_ip == 0 .or. neighboring_el == 0 ) then ! at free surfaces ... if ( neighboring_ip == 0 .or. neighboring_el == 0 ) then ! at free surfaces ...
@ -950,11 +967,11 @@ do n = 1,6
mesh_ipCenterOfGravity(:,neighboring_ip,neighboring_el) - mesh_ipCenterOfGravity(:,ip,el) ) mesh_ipCenterOfGravity(:,neighboring_ip,neighboring_el) - mesh_ipCenterOfGravity(:,ip,el) )
endif endif
endif endif
enddo enddo
invPositionDifference = math_inv3x3(neighboring_position((/1,3,5/),:) - neighboring_position((/2,4,6/),:)) invPositionDifference = math_inv3x3(neighboring_position((/1,3,5/),:) - neighboring_position((/2,4,6/),:))
do s = 1,ns do s = 1,ns
lattice2slip = transpose( reshape( (/ lattice_st(:, constitutive_nonlocal_slipSystemLattice(s,myInstance), myStructure), & lattice2slip = transpose( reshape( (/ lattice_st(:, constitutive_nonlocal_slipSystemLattice(s,myInstance), myStructure), &
lattice_sd(:, constitutive_nonlocal_slipSystemLattice(s,myInstance), myStructure), & lattice_sd(:, constitutive_nonlocal_slipSystemLattice(s,myInstance), myStructure), &
@ -980,7 +997,9 @@ do s = 1,ns
Tdislocation_v = Tdislocation_v + math_Mandel33to6( math_mul33x33(transpose(lattice2slip), math_mul33x33(sigma, lattice2slip) ) ) Tdislocation_v = Tdislocation_v + math_Mandel33to6( math_mul33x33(transpose(lattice2slip), math_mul33x33(sigma, lattice2slip) ) )
enddo enddo
endif
!********************************************************************** !**********************************************************************

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@ -230,6 +230,7 @@ rhoSglScrewPos0 1e11 0 0 0 # Initial positive screw single
rhoSglScrewNeg0 1e11 0 0 0 # Initial negative screw single dislocation density in m/m**3 rhoSglScrewNeg0 1e11 0 0 0 # Initial negative screw single dislocation density in m/m**3
rhoDipEdge0 1e8 0 0 0 # Initial edge dipole dislocation density in m/m**3 rhoDipEdge0 1e8 0 0 0 # Initial edge dipole dislocation density in m/m**3
rhoDipScrew0 1e8 0 0 0 # Initial screw dipole dislocation density in m/m**3 rhoDipScrew0 1e8 0 0 0 # Initial screw dipole dislocation density in m/m**3
rhoSglScatter 0 # standard deviation of scatter in initial single dislocation density
r 10e-6 # cutoff radius for dislocation stress in m r 10e-6 # cutoff radius for dislocation stress in m
vs 3500 0 0 0 # maximum dislocation velocity (velocity of sound) in m/s vs 3500 0 0 0 # maximum dislocation velocity (velocity of sound) in m/s
dDipMinEdge 1e-9 0 0 0 # minimum distance for stable edge dipoles in m dDipMinEdge 1e-9 0 0 0 # minimum distance for stable edge dipoles in m

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@ -1957,6 +1957,51 @@ endif
!********************************************************************
! draw a random sample from Gauss variable
!********************************************************************
function math_sampleGaussVar(meanvalue, stddev, width)
use prec, only: pReal, pInt
implicit none
!*** input variables
real(pReal), intent(in) :: meanvalue, & ! meanvalue of gauss distribution
stddev ! standard deviation of gauss distribution
real(pReal), intent(in), optional :: width ! width of considered values as multiples of standard deviation
!*** output variables
real(pReal) math_sampleGaussVar
!*** local variables
real(pReal), dimension(2) :: rnd ! random numbers
real(pReal) scatter, & ! normalized scatter around meanvalue
myWidth
if (stddev == 0.0) then
math_sampleGaussVar = meanvalue
return
endif
if (present(width)) then
myWidth = width
else
myWidth = 3.0_pReal ! use +-3*sigma as default value for scatter
endif
do
call halton(2, rnd)
scatter = myWidth * (2.0_pReal * rnd(1) - 1.0_pReal)
if (rnd(2) <= exp(-0.5_pReal * scatter ** 2.0_pReal)) & ! test if scattered value is drawn
exit
enddo
math_sampleGaussVar = scatter * stddev
endfunction
!**************************************************************** !****************************************************************
pure subroutine math_pDecomposition(FE,U,R,error) pure subroutine math_pDecomposition(FE,U,R,error)
!-----FE = R.U !-----FE = R.U