Actual dislocation loop generation algorithm alongside dislgen command

master
Alex Selimov 5 years ago
parent ec7980ff0b
commit 20546dc267

@ -140,13 +140,17 @@ This options adds an arbitrarily oriented dislocation into your model based on u
### Option disloop ### Option disloop
```` ````
-disloop loop_normal loop_size x y z -disloop loop_normal radius x y z bx by bz poisson
```` ````
This option deletes vacancies on a plane which when minimized should result in a dislocation loop structure. The arguments are below: This option deletes vacancies on a plane which when minimized should result in a dislocation loop structure. The arguments are below:
`dim` - The box dimension which defines the normal to the loop plane. As of now this dimension must be a closed back direction, meaning that for fcc a box dimension has to be of the (111) family of planes `dim` - The box dimension which defines the normal to the loop plane. As of now this dimension must be a closed back direction, meaning that for fcc a box dimension has to be of the (111) family of planes. Either `x`, `y`, or `z`.
`n` - The number of atoms to delete on the loop plane `n` - The number of atoms to delete on the loop plane
`x y z` - The centroid of the loop. As a note, `x y z` - The centroid of the loop.
`bx by bz` - The burgers vector for the dislocation
`poisson` - Poisson ratio for continuum solution

@ -315,7 +315,7 @@ module io
write(11,3) node_num write(11,3) node_num
write(11,19) max_ng_node write(11,19) max_ng_node
write(11,4) lattice_types write(11,4) lattice_types
write(11,2) atom_num write(11,5) atom_num
write(11,6) 1 !Grain_num is ignored write(11,6) 1 !Grain_num is ignored
write(11,16) lattice_types, atom_types write(11,16) lattice_types, atom_types
write(11,21) write(11,21)

@ -0,0 +1,520 @@
module opt_disl
!This module contains all code associated with dislocations
use parameters
use elements
use subroutines
use box
implicit none
real(kind=dp), dimension(3) :: line, slip_plane, centroid!dislocation line, slip plane vectors, centroid,
real(kind=dp) :: burgers(3) !burgers vector of loop
real(kind=dp) :: poisson, char_angle, lattice_parameter!Poisson ratio and character angle, lattice_parameter for burgers vector
character(len=10) :: lattice
character(len=1) :: loop_normal
real(kind=dp) :: loop_radius !Dislocation loop radius
real(kind=dp) :: b !burgers vector
public
contains
subroutine dislocation(option, arg_pos)
!Main calling function for all codes related to dislocations
character(len=100), intent(in) :: option
integer, intent(inout) :: arg_pos
select case(trim(adjustl(option)))
case('-dislgen')
call parse_dislgen(arg_pos)
call dislgen
case('-disloop')
call parse_disloop(arg_pos)
call disloop
end select
end subroutine dislocation
subroutine parse_dislgen(arg_pos)
!Parse dislgen command
integer, intent(inout) :: arg_pos
integer :: i,arglen
character(len=8) :: ori_string
character(len=100) :: textholder
!Parse all of the commands
arg_pos = arg_pos + 1
line(:) = 0.0_dp
call get_command_argument(arg_pos, ori_string, arglen)
if (arglen==0) STOP "Missing line vector in dislgen command"
call parse_ori_vec(ori_string, line)
arg_pos=arg_pos + 1
slip_plane(:) = 0.0_dp
call get_command_argument(arg_pos, ori_string, arglen)
if (arglen==0) STOP "Missing plane vector in dislgen command"
call parse_ori_vec(ori_string, slip_plane)
do i = 1, 3
arg_pos = arg_pos + 1
call get_command_argument(arg_pos, textholder, arglen)
if (arglen==0) STOP "Missing centroid in dislgen command"
call parse_pos(i, textholder, centroid(i))
end do
print *, centroid
arg_pos = arg_pos + 1
call get_command_argument(arg_pos, textholder, arglen)
if (arglen==0) STOP "Missing character angle in dislgen command"
read(textholder, *) char_angle
arg_pos = arg_pos + 1
call get_command_argument(arg_pos, textholder, arglen)
if (arglen==0) STOP "Missing poisson in dislgen command"
read(textholder, *) poisson
arg_pos = arg_pos + 1
call get_command_argument(arg_pos, lattice, arglen)
if (arglen==0) STOP "Missing lattice in dislgen command"
arg_pos = arg_pos + 1
call get_command_argument(arg_pos, textholder, arglen)
if (arglen==0) STOP "Missing lattice parameter in dislgen command"
read(textholder, *) lattice_parameter
arg_pos = arg_pos + 1
!Now set the vurgers vector based on the lattice paarameter and lattice type
select case(lattice)
case('fcc')
b = lattice_parameter / sqrt(2.0_dp)
! case('bcc')
! b = lattice_parameter * sqrt(3.0_dp) / 2.0_dp
case default
print *, 'Error: Lattice structure', lattice, ' is not accepted for dislgen option'
STOP
end select
end subroutine parse_dislgen
subroutine dislgen
!This subroutine creates the actual dislocation
integer :: i, sub_box, inod, ibasis
real(kind=dp) :: ss_ori(3,3), ss_inv(3,3), be, bs, slipx(3), disp_transform(3,3), inv_transform(3,3), &
actan, r(3), disp(3)
!Calculate screw and edge burgers vectors
be = sin(char_angle*pi/180.0_dp)*b
bs = cos(char_angle*pi/180.0_dp)*b
!Figure out which sub box you are in so you can access it's orientation, this code will not work
!with overlapping sub_boxes
do i = 1, sub_box_num
if(in_block_bd(centroid, sub_box_bd(:,i))) then
sub_box = i
exit
end if
end do
!Construct the slip system orientation matrix in an unrotated system
slipx = cross_product(slip_plane, line)
ss_ori(1,:) = unitvec(3,slipx)
ss_ori(2,:) = unitvec(3,slip_plane)
ss_ori(3,:) = unitvec(3,line)
call matrix_inverse(ss_ori, 3, ss_inv)
!Apply the rotation
disp_transform = matmul(sub_box_ori(:,:,i), ss_inv)
call matrix_inverse(disp_transform,3,inv_transform)
if(atom_num > 0) then
do i = 1, atom_num
r=r_atom(:,i) - centroid
r=matmul(inv_transform, r)
if (r(1) == 0) then
actan=pi/2
else
actan = datan2(r(2),r(1))
end if
if ((r(1)**2 + r(2)**2) == 0) cycle
!This is the elastic displacement field for dislocation according to Hirth and Lowe
disp(1) = be/(2.0_dp*pi) * (actan + (r(1)*r(2))/(2.0_dp*(1.0_dp-poisson)*(r(1)**2.0_dp + r(2)**2.0_dp)))
disp(2) = -be/(2.0_dp*pi)*((1.0_dp-2.0_dp*poisson)/(4.0_dp-4.0_dp*poisson) * &
log(r(1)**2.0_dp + r(2)**2.0_dp) &
+ (r(1)**2.0_dp - r(2)**2.0_dp)/(4.0_dp*(1.0_dp-poisson)&
*(r(1)**2.0_dp+r(2)**2.0_dp)))
disp(3) = bs/(2.0_dp*pi) * actan
!This transforms the displacement to the correct orientation
disp = matmul(disp_transform, disp)
r_atom(:,i) = r_atom(:,i) + disp
end do
end if
if(ele_num > 0) then
do i = 1, ele_num
do inod=1, ng_node(lat_ele(i))
do ibasis = 1, basisnum(lat_ele(i))
r = r_node(:,ibasis,inod,i)
r = matmul(inv_transform, r)
if (r(1) == 0) then
actan = pi/2
else
actan = datan2(r(2),r(1))
end if
if ((r(1)**2 + r(2)**2) == 0) cycle
!This is the elastic displacement field for dislocation according to Hirth and Lowe
disp(1) = be/(2.0_dp*pi) * (actan + (r(1)*r(2))/(2.0_dp*(1.0_dp-poisson)*(r(1)**2.0_dp + r(2)**2.0_dp)))
disp(2) = -be/(2.0_dp*pi)*((1.0_dp-2.0_dp*poisson)/(4.0_dp-4.0_dp*poisson) * &
log(r(1)**2.0_dp + r(2)**2.0_dp) &
+ (r(1)**2.0_dp - r(2)**2.0_dp)/(4.0_dp*(1.0_dp-poisson)&
*(r(1)**2.0_dp+r(2)**2.0_dp)))
disp(3) = bs/(2.0_dp*pi) * actan
disp = matmul(disp_transform, disp)
r_node(:,ibasis,inod,i) = r_node(:,ibasis,inod,i) + disp
end do
end do
end do
end if
end subroutine dislgen
subroutine parse_disloop(arg_pos)
!This subroutine parses the disloop command
integer, intent(inout) :: arg_pos
integer :: i,arglen, sbox
character(len=8) :: ori_string
character(len=100) :: textholder
!Parse all of the commands
arg_pos = arg_pos + 1
loop_normal = ' '
call get_command_argument(arg_pos, loop_normal, arglen)
if (arglen==0) STOP "Missing loop_normal in disloop command"
!Convert the loop_normal to the dimension
select case(loop_normal)
case('x','X', 'y', 'Y', 'z', 'Z')
continue
case default
print *, "Dimension argument must either be x, y, or z not", loop_normal
stop 3
end select
arg_pos = arg_pos + 1
loop_radius = 0
call get_command_argument(arg_pos, textholder, arglen)
if (arglen==0) STOP "Missing loop_size in disloop command"
read(textholder, *) loop_radius
do i = 1, 3
arg_pos = arg_pos + 1
call get_command_argument(arg_pos, textholder, arglen)
if (arglen==0) STOP "Missing centroid in disloop command"
call parse_pos(i, textholder, centroid(i))
end do
burgers(:) = 0.0_dp
do i = 1, 3
arg_pos = arg_pos + 1
call get_command_argument(arg_pos, textholder, arglen)
if (arglen==0) STOP "Missing burgers vector in disloop command"
read(textholder, *) burgers(i)
end do
arg_pos = arg_pos + 1
call get_command_argument(arg_pos, textholder, arglen)
if (arglen==0) STOP "Missing poisson ratio in disloop command"
read(textholder, *) poisson
arg_pos = arg_pos + 1
!Now check to make sure that the dimension selected is actually a 1 1 1 direction.
! call in_sub_box(centroid, sbox)
! if(.not.((abs(sub_box_ori(loop_normal,1,sbox)) == abs(sub_box_ori(loop_normal,2,sbox))).and. &
! (abs(sub_box_ori(loop_normal,2,sbox)) == abs(sub_box_ori(loop_normal,3,sbox))).and. &
! (abs(sub_box_ori(loop_normal,3,sbox)) == abs(sub_box_ori(loop_normal,1,sbox))))) then
! print *, "The selected dimension ", loop_normal, " for sub_box ", sbox, " is ", &
! sub_box_ori(loop_normal,:,sbox), " which is not in the (111) family of planes"
! STOP 3
! end if
end subroutine
!Code for the creation of dislocation loops is based on functions from atomsk
!which is available from https://atomsk.univ-lille.fr/. They have been adapted to fit cacmb.
subroutine disloop
!This subroutine applies the displacement field for a dislocation loop to all atoms and elements.
integer :: a1, a2, a3 !New directions
integer :: i, j, inod, ibasis, Npoints
real(kind = dp) :: perimeter, angle, theta, omega, xA(3), xB(3), xC(3), u(3)
real(kind=dp), dimension(:,:), allocatable :: xloop !coordinate of points forming loop
if(allocated(xLoop)) deallocate(xLoop)
!Define new directions
select case(loop_normal)
case('x','X')
!Loop in (y,z) plane
a1 = 2
a2 = 3
a3 = 1
case('y','Y')
!Loop in (x,z) plane
a1 = 3
a2 = 1
a3 = 2
case default
!Loop in (x,y) plane
a1 = 1
a2 = 2
a3 = 3
end select
!Calculate loop perimeter
perimeter = 2.0_dp*pi*loop_radius
!Define the number of points forming the loop
! The following criteria are used as a trade-off between
! good accuracy and computational efficiency:
! - each dislocation segment should have a length of 5 angströms;
! - the loop should contain at least 3 points
! (for very small loops, this will result in segments shorter than 5 A);
! - there should not be more than 100 points
! (for very large loops, this will result in segments longer than 5 A).
Npoints = MAX( 3 , MIN( NINT(perimeter/5.d0) , 100 ) )
!angle between two consecutive points
theta = 2.0_dp*pi / dble(Npoints)
!allocate xLoop
allocate(xLoop(Npoints,3))
xLoop(:,:) = 0.0_dp
!Calculate the position of each point in the loop
angle = 0.0_dp
do i = 1, size(xLoop,1)
xLoop(i,a1) = centroid(a1) + loop_radius*dcos(angle)
xLoop(i,a2) = centroid(a2) + loop_radius*dsin(angle)
xLoop(i,a3) = centroid(a3)
! Increment angle for next point
angle = angle + theta
end do
!Now actually calculate the displacement created by a loop for every atom
do i = 1, atom_num
u = 0.0_dp
omega = 0.0_dp
xC(:) = centroid - r_atom(:,i)
!Loop over all dislocation segments
do j = 1, size(xLoop,1)
!Coordinates of point A
if (j ==1) then
xA(:) = xLoop(size(xLoop,1),:) - r_atom(:,i)
else
xA(:) = xLoop(j-1, :) - r_atom(:,i)
end if
!Coordinates of point B
xB(:) = xLoop(j,:) - r_atom(:,i)
!Displacement due to solid angle
omega = omega + SolidAngle(xA, xB, xC)
!Displacement due to elasticity
u(:) = u(:) + DisloSeg_displacement_iso(xA, xB, burgers(:), poisson)
end do
!Total displacement
u=u(:) + burgers(:) * omega
!Apply displacement to atom
r_atom(:,i) = r_atom(:,i) + u(:)
end do
!Repeat for element nodes
do i = 1, ele_num
do inod =1, ng_node(lat_ele(i))
do ibasis = 1, basisnum(lat_ele(i))
u = 0.0_dp
omega = 0.0_dp
xC(:) = centroid - r_node(:,ibasis,inod,i)
!Loop over all dislocation segments
do j = 1, size(xLoop,1)
!Coordinates of point A
if (j ==1) then
xA(:) = xLoop(size(xLoop,1),:) - r_node(:,ibasis,inod,i)
else
xA(:) = xLoop(j-1, :) - r_node(:,ibasis,inod,i)
end if
!Coordinates of point B
xB(:) = xLoop(j,:) - r_node(:,ibasis,inod,i)
!Displacement due to solid angle
omega = omega + SolidAngle(xA, xB, xC)
!Displacement due to elasticity
u(:) = u(:) + DisloSeg_displacement_iso(xA, xB, burgers(:), poisson)
end do
!Total displacement
u=u(:) + burgers(:) * omega
!Apply displacement to atom
r_node(:,ibasis,inod,i) = r_node(:,ibasis,inod,i) + u(:)
end do
end do
end do
return
end subroutine
!********************************************************
! SOLIDANGLE
! Calculate solid angle (normalized by 4*pi) used to obtain the
! displacement created by a dislocation triangle loop ABC at the origin
! (field point = origin)
! Ref.: Van Oosterom, A. and Strackee, J.,
! The Solid Angle of a Plane Triangle,
! IEEE Transactions on Biomedical Engineering BME-30, 125 (1983).
!********************************************************
FUNCTION SolidAngle(xA, xB, xC) RESULT(Omega)
!
IMPLICIT NONE
!
! Extremities of the triangle loop
REAL(dp),DIMENSION(3),INTENT(IN) :: xA, xB, xC
!
! Solid angle (normalized by 4*pi)
REAL(dp):: omega
REAL(dp),PARAMETER:: factor=1.d0/(2.d0*pi)
!
REAL(dp) :: rA, rB, rC, numerator, denominator
!
rA = norm2(xA)
rB = norm2(xB)
rC = norm2(xC)
!
numerator = TRIPLE_PRODUCT( xA, xB, xC )
denominator = rA*rB*rC + DOT_PRODUCT( xA, xB )*rC &
& + DOT_PRODUCT( xB, xC )*rA + DOT_PRODUCT( xC, xA )*rB
!
omega = factor*ATAN2( numerator, denominator )
!
END FUNCTION SolidAngle
!********************************************************
! DISLOSEG_DISPLACEMENT_ISO
! Calculate displacement created by dislocation segment AB
! once the solid angle part has been removed
! Isotropic elastic calculation with nu Poisson coef.
! Ref.: Eq. (1) in Barnett, D. M.
! The Displacement Field of a Triangular Dislocation Loop
! Philos. Mag. A, 1985, 51, 383-387
!********************************************************
FUNCTION DisloSeg_displacement_iso(xA, xB, b, nu) RESULT(u)
!
IMPLICIT NONE
REAL(dp),DIMENSION(3),INTENT(IN):: xA, xB ! Extremities of the segment
REAL(dp),DIMENSION(3),INTENT(IN):: b ! Burgers vector
REAL(dp),INTENT(IN):: nu ! Poisson coefficient
REAL(dp),DIMENSION(3):: u ! Displacement
REAL(dp):: rA, rB
REAL(dp),DIMENSION(1:3):: tAB, nAB
!
rA = norm2(xA)
rB = norm2(xB)
!
! Tangent vector
tAB(:) = xB(:) - xA(:)
tAB(:) = tAB(:)/norm2(tAB)
!
! Normal vector
nAB(:) = CROSS_PRODUCT(xA,xB)
nAB(:) = nAB(:)/norm2(nAB)
!
u(:) = ( -(1.d0-2.d0*nu)*CROSS_PRODUCT(b, tAB)* &
& LOG( (rB + DOT_PRODUCT(xB,tAB))/(rA + DOT_PRODUCT(xA,tAB)) ) &
& + DOT_PRODUCT(b,nAB)*CROSS_PRODUCT(xB/rB-xA/rA,nAB) ) &
& /(8.d0*pi*(1.d0-nu))
!
END FUNCTION DisloSeg_displacement_iso
!
!This code simply creates a planar vacancy cluster and does not apply the dislocation loop displacement field.
! subroutine disloop
! !This subroutine actually creates the dislocation loop.
! real(kind=dp) :: neighbor_dis(loop_size), temp_box(6), dis
! integer :: i, j, index(loop_size)
! neighbor_dis(:) = HUGE(1.0_dp)
! index(:) = 0
! !First find the nearest atom to the centroid
! do i = 1, atom_num
! if(norm2(r_atom(:,i) - centroid) < neighbor_dis(1)) then
! neighbor_dis(1) = norm2(r_atom(:,i) - centroid)
! index(1) = i
! end if
! end do
! !Define a new box, this box tries to isolate all atoms on the plane of the atom
! !closest to the user defined centroid.
! temp_box(:) = box_bd(:)
! temp_box(2*loop_normal) = r_atom(loop_normal,index(1)) + 10.0_dp**(-2.0_dp)
! temp_box(2*loop_normal-1) = r_atom(loop_normal,index(1)) - 10.0_dp**(-2.0_dp)
! !Now reset the list for the scanning algorithm
! index(1) = 0
! neighbor_dis(1) = HUGE(1.0_dp)
! !Now scan over all atoms again and find the closest loop_size number of atoms to the initial atom
! !that reside on the same plane.
! do i = 1, atom_num
! !Check to see if it is on the same plane
! if (in_block_bd(r_atom(:,i), temp_box)) then
! dis = norm2(r_atom(:,i) - centroid)
! do j = 1, loop_size
! !Check to see if it is closer than other atoms
! if (dis < neighbor_dis(j)) then
! !Move values in the neighbor array and add the new neighbor
! if(j < loop_size) then
! neighbor_dis(j+1:loop_size) = neighbor_dis(j:loop_size-1)
! index(j+1:loop_size) = index(j:loop_size-1)
! end if
! neighbor_dis(j) = dis
! index(j) = i
! exit
! end if
! end do
! end if
! end do
! !Now delete the atoms
! call delete_atoms(loop_size, index)
! return
! end subroutine disloop
end module opt_disl
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