* 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'
case (237)
msg = 'Non-positive obstacle strength'
case (238)
msg = 'Negative scatter for dislocation density'
case (240)
msg = 'Non-positive Taylor factor'
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_tauObs, & ! obstacle strength in Pa
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_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
@ -222,6 +223,7 @@ allocate(constitutive_nonlocal_d0(maxNinstance))
allocate(constitutive_nonlocal_tauObs(maxNinstance))
allocate(constitutive_nonlocal_vs(maxNinstance))
allocate(constitutive_nonlocal_fattack(maxNinstance))
allocate(constitutive_nonlocal_rhoSglScatter(maxNinstance))
constitutive_nonlocal_CoverA = 0.0_pReal
constitutive_nonlocal_C11 = 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_vs = 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_rhoSglEdgeNeg0(lattice_maxNslipFamily, maxNinstance))
@ -349,6 +352,8 @@ do
constitutive_nonlocal_vs(i) = IO_floatValue(line,positions,2)
case('fattack')
constitutive_nonlocal_fattack(i) = IO_floatValue(line,positions,2)
case('rhosglscatter')
constitutive_nonlocal_rhoSglScatter(i) = IO_floatValue(line,positions,2)
end select
endif
enddo
@ -392,6 +397,7 @@ enddo
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_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
@ -629,11 +635,13 @@ endsubroutine
!*********************************************************************
!* initial microstructural state (just the "basic" states) *
!*********************************************************************
pure function constitutive_nonlocal_stateInit(myInstance)
function constitutive_nonlocal_stateInit(myInstance)
use prec, only: pReal, &
pInt
use lattice, only: lattice_maxNslipFamily
use math, only: math_sampleGaussVar
implicit none
!*** input variables
@ -661,8 +669,9 @@ integer(pInt) ns, & ! short notation f
f, & ! index of lattice family
from, &
upto, &
s ! index of slip system
s, & ! index of slip system
i
real(pReal), dimension(2) :: noise
constitutive_nonlocal_stateInit = 0.0_pReal
ns = constitutive_nonlocal_totalNslip(myInstance)
@ -670,12 +679,17 @@ ns = constitutive_nonlocal_totalNslip(myInstance)
!*** set the basic state variables
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))
rhoSglEdgePos(from:upto) = constitutive_nonlocal_rhoSglEdgePos0(f, myInstance)
rhoSglEdgeNeg(from:upto) = constitutive_nonlocal_rhoSglEdgeNeg0(f, myInstance)
rhoSglScrewPos(from:upto) = constitutive_nonlocal_rhoSglScrewPos0(f, myInstance)
rhoSglScrewNeg(from:upto) = constitutive_nonlocal_rhoSglScrewNeg0(f, myInstance)
do s = from,upto
do i = 1,2
noise(i) = math_sampleGaussVar(0.0_pReal, constitutive_nonlocal_rhoSglScatter(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
rhoSglEdgeNegUsed(from:upto) = 0.0_pReal
rhoSglScrewPosUsed(from:upto) = 0.0_pReal
@ -905,82 +919,87 @@ forall (s = 1:ns) &
!*** calculate the dislocation stress of the neighboring excess dislocation densities
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) &
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))
do n = 1,6
neighboring_el = mesh_ipNeighborhood(1,n,ip,el)
neighboring_ip = mesh_ipNeighborhood(2,n,ip,el)
if ( neighboring_ip == 0 .or. neighboring_el == 0 ) then ! at free surfaces ...
neighboring_el = el ! ... use central values instead of neighboring values
neighboring_ip = ip
neighboring_position(n,:) = 0.0_pReal
neighboring_rhoExcess(n,:,:) = rhoExcess
elseif (phase_localConstitution(material_phase(1,neighboring_ip,neighboring_el))) then ! for neighbors with local constitution
neighboring_el = el ! ... use central values instead of neighboring values
neighboring_ip = ip
neighboring_position(n,:) = 0.0_pReal
neighboring_rhoExcess(n,:,:) = rhoExcess
elseif (myStructure /= &
constitutive_nonlocal_structure(phase_constitutionInstance(material_phase(1,neighboring_ip,neighboring_el)))) then ! for neighbors with different crystal structure
neighboring_el = el ! ... use central values instead of neighboring values
neighboring_ip = ip
neighboring_position(n,:) = 0.0_pReal
neighboring_rhoExcess(n,:,:) = rhoExcess
else
forall (s = 1:ns, c = 1:2) &
neighboring_rhoExcess(n,c,s) = state(g,neighboring_ip,neighboring_el)%p((2*c-2)*ns+s) &
+ abs(state(g,neighboring_ip,neighboring_el)%p((2*c+2)*ns+s)) &
- state(g,neighboring_ip,neighboring_el)%p((2*c-1)*ns+s) &
- abs(state(g,neighboring_ip,neighboring_el)%p((2*c+3)*ns+s))
transmissivity = sum(constitutive_nonlocal_compatibility(2,:,:,n,ip,el)**2.0_pReal, 1)
if ( any(transmissivity < 0.99_pReal) ) then ! at grain boundary (=significantly decreased transmissivity) ...
neighboring_el = el ! ... use central values instead of neighboring values
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)) &
- 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
neighboring_el = mesh_ipNeighborhood(1,n,ip,el)
neighboring_ip = mesh_ipNeighborhood(2,n,ip,el)
if ( neighboring_ip == 0 .or. neighboring_el == 0 ) then ! at free surfaces ...
neighboring_el = el ! ... use central values instead of neighboring values
neighboring_ip = ip
neighboring_position(n,:) = 0.0_pReal
neighboring_rhoExcess(n,:,:) = rhoExcess
else
neighboring_F = math_mul33x33(Fe(:,:,g,neighboring_ip,neighboring_el), Fp(:,:,g,neighboring_ip,neighboring_el))
neighboring_position(n,:) = &
0.5_pReal * math_mul33x3( math_mul33x33(invFe,neighboring_F) + Fp(:,:,g,ip,el), &
mesh_ipCenterOfGravity(:,neighboring_ip,neighboring_el) - mesh_ipCenterOfGravity(:,ip,el) )
endif
endif
enddo
invPositionDifference = math_inv3x3(neighboring_position((/1,3,5/),:) - neighboring_position((/2,4,6/),:))
do s = 1,ns
lattice2slip = transpose( reshape( (/ lattice_st(:, constitutive_nonlocal_slipSystemLattice(s,myInstance), myStructure), &
lattice_sd(:, constitutive_nonlocal_slipSystemLattice(s,myInstance), myStructure), &
lattice_sn(:, constitutive_nonlocal_slipSystemLattice(s,myInstance), myStructure) /), &
(/ 3,3 /) ) )
rhoExcessDifference = neighboring_rhoExcess((/1,3,5/),:,s) - neighboring_rhoExcess((/2,4,6/),:,s)
forall (c = 1:2) &
disloGradients(:,c) = math_mul33x3( lattice2slip, math_mul33x3(invPositionDifference, rhoExcessDifference(:,c)) )
elseif (phase_localConstitution(material_phase(1,neighboring_ip,neighboring_el))) then ! for neighbors with local constitution
neighboring_el = el ! ... use central values instead of neighboring values
neighboring_ip = ip
neighboring_position(n,:) = 0.0_pReal
neighboring_rhoExcess(n,:,:) = rhoExcess
elseif (myStructure /= &
constitutive_nonlocal_structure(phase_constitutionInstance(material_phase(1,neighboring_ip,neighboring_el)))) then ! for neighbors with different crystal structure
neighboring_el = el ! ... use central values instead of neighboring values
neighboring_ip = ip
neighboring_position(n,:) = 0.0_pReal
neighboring_rhoExcess(n,:,:) = rhoExcess
else
forall (s = 1:ns, c = 1:2) &
neighboring_rhoExcess(n,c,s) = state(g,neighboring_ip,neighboring_el)%p((2*c-2)*ns+s) &
+ abs(state(g,neighboring_ip,neighboring_el)%p((2*c+2)*ns+s)) &
- state(g,neighboring_ip,neighboring_el)%p((2*c-1)*ns+s) &
- abs(state(g,neighboring_ip,neighboring_el)%p((2*c+3)*ns+s))
transmissivity = sum(constitutive_nonlocal_compatibility(2,:,:,n,ip,el)**2.0_pReal, 1)
if ( any(transmissivity < 0.99_pReal) ) then ! at grain boundary (=significantly decreased transmissivity) ...
neighboring_el = el ! ... use central values instead of neighboring values
neighboring_ip = ip
neighboring_position(n,:) = 0.0_pReal
neighboring_rhoExcess(n,:,:) = rhoExcess
else
neighboring_F = math_mul33x33(Fe(:,:,g,neighboring_ip,neighboring_el), Fp(:,:,g,neighboring_ip,neighboring_el))
neighboring_position(n,:) = &
0.5_pReal * math_mul33x3( math_mul33x33(invFe,neighboring_F) + Fp(:,:,g,ip,el), &
mesh_ipCenterOfGravity(:,neighboring_ip,neighboring_el) - mesh_ipCenterOfGravity(:,ip,el) )
endif
endif
enddo
sigma = 0.0_pReal
sigma(1,1) = + (-0.06066_pReal + nu*0.41421_pReal) / (1.0_pReal-nu) * disloGradients(3,1)
sigma(2,2) = + 0.32583_pReal / (1.0_pReal-nu) * disloGradients(3,1)
sigma(3,3) = + 0.14905_pReal / (1.0_pReal-nu) * disloGradients(3,1)
sigma(1,2) = + 0.20711_pReal * disloGradients(3,2)
sigma(2,3) = - 0.08839_pReal / (1.0_pReal-nu) * disloGradients(2,1) - 0.20711_pReal * disloGradients(1,2)
sigma(2,1) = sigma(1,2)
sigma(3,2) = sigma(2,3)
invPositionDifference = math_inv3x3(neighboring_position((/1,3,5/),:) - neighboring_position((/2,4,6/),:))
forall (i=1:3, j=1:3) &
sigma(i,j) = sigma(i,j) * constitutive_nonlocal_Gmod(myInstance) * constitutive_nonlocal_burgersPerSlipSystem(s,myInstance) &
* constitutive_nonlocal_R(myInstance)**2.0_pReal
Tdislocation_v = Tdislocation_v + math_Mandel33to6( math_mul33x33(transpose(lattice2slip), math_mul33x33(sigma, lattice2slip) ) )
do s = 1,ns
lattice2slip = transpose( reshape( (/ lattice_st(:, constitutive_nonlocal_slipSystemLattice(s,myInstance), myStructure), &
lattice_sd(:, constitutive_nonlocal_slipSystemLattice(s,myInstance), myStructure), &
lattice_sn(:, constitutive_nonlocal_slipSystemLattice(s,myInstance), myStructure) /), &
(/ 3,3 /) ) )
rhoExcessDifference = neighboring_rhoExcess((/1,3,5/),:,s) - neighboring_rhoExcess((/2,4,6/),:,s)
forall (c = 1:2) &
disloGradients(:,c) = math_mul33x3( lattice2slip, math_mul33x3(invPositionDifference, rhoExcessDifference(:,c)) )
enddo
sigma = 0.0_pReal
sigma(1,1) = + (-0.06066_pReal + nu*0.41421_pReal) / (1.0_pReal-nu) * disloGradients(3,1)
sigma(2,2) = + 0.32583_pReal / (1.0_pReal-nu) * disloGradients(3,1)
sigma(3,3) = + 0.14905_pReal / (1.0_pReal-nu) * disloGradients(3,1)
sigma(1,2) = + 0.20711_pReal * disloGradients(3,2)
sigma(2,3) = - 0.08839_pReal / (1.0_pReal-nu) * disloGradients(2,1) - 0.20711_pReal * disloGradients(1,2)
sigma(2,1) = sigma(1,2)
sigma(3,2) = sigma(2,3)
forall (i=1:3, j=1:3) &
sigma(i,j) = sigma(i,j) * constitutive_nonlocal_Gmod(myInstance) * constitutive_nonlocal_burgersPerSlipSystem(s,myInstance) &
* constitutive_nonlocal_R(myInstance)**2.0_pReal
Tdislocation_v = Tdislocation_v + math_Mandel33to6( math_mul33x33(transpose(lattice2slip), math_mul33x33(sigma, lattice2slip) ) )
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
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
rhoSglScatter 0 # standard deviation of scatter in initial single dislocation density
r 10e-6 # cutoff radius for dislocation stress in m
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

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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)
!-----FE = R.U