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JuliaFEM.jl/src/problems_mortar_2d_autodiff.jl
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Jukka Aho 9ad66be08b Make code 0.6 compatible (#128)
* running v0.6 conversion code proposed by @ovainola in #108.
* change travis so that build is done using 0.6
* documentation is build from 0.6
* fix most of deprecation warnings
* fix test to pass 0.6
2017-07-20 20:46:57 +03:00

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8.6 KiB
Julia

# This file is a part of JuliaFEM.
# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE.md
using ForwardDiff
# forwarddiff version of mesh tying in 2d
function project_from_master_to_slave{E<:MortarElements2D}(
slave_element::Element{E}, x1_::DVTI, n1_::DVTI, x2::Vector, time::Float64;
tol=1.0e-10, max_iterations=20)
x1(xi1) = vec(get_basis(slave_element, [xi1], time))*x1_
dx1(xi1) = vec(get_dbasis(slave_element, [xi1], time))*x1_
n1(xi1) = vec(get_basis(slave_element, [xi1], time))*n1_
dn1(xi1) = vec(get_dbasis(slave_element, [xi1], time))*n1_
cross2(a, b) = cross([a; 0], [b; 0])[3]
R(xi1) = cross2(x1(xi1)-x2, n1(xi1))
dR(xi1) = cross2(dx1(xi1), n1(xi1)) + cross2(x1(xi1)-x2, dn1(xi1))
xi1 = 0.0
dxi1 = 0.0
for i=1:max_iterations
dxi1 = -R(xi1)/dR(xi1)
xi1 += dxi1
if norm(dxi1) < tol
return xi1
end
end
info("x1 = $(ForwardDiff.get_value(x1_.data))")
info("n1 = $(ForwardDiff.get_value(n1_.data))")
info("x2 = $(ForwardDiff.get_value(x2))")
info("xi1 = $(ForwardDiff.get_value(xi1)), dxi1 = $(ForwardDiff.get_value(dxi1))")
info("-R(xi1) = $(ForwardDiff.get_value(-R(xi1)))")
info("dR(xi1) = $(ForwardDiff.get_value(dR(xi1)))")
error("find projection from master to slave: did not converge")
end
function project_from_slave_to_master{E<:MortarElements2D}(
master_element::Element{E}, x1::Vector, n1::Vector, x2_::DVTI, time::Float64;
tol=1.0e-10, max_iterations=20)
x2(xi2) = vec(get_basis(master_element, [xi2], time))*x2_
dx2(xi2) = vec(get_dbasis(master_element, [xi2], time))*x2_
cross2(a, b) = cross([a; 0], [b; 0])[3]
R(xi2) = cross2(x2(xi2)-x1, n1)
dR(xi2) = cross2(dx2(xi2), n1)
xi2 = 0.0
dxi2 = 0.0
for i=1:max_iterations
dxi2 = -R(xi2) / dR(xi2)
xi2 += dxi2
if norm(dxi2) < tol
return xi2
end
end
error("find projection from slave to master: did not converge, last val: $xi2 and $dxi2")
end
""" 2d mesh tie using ForwardDiff.
Construct .. + fc*la and C(d,la)=0
"""
function assemble!(problem::Problem{Mortar}, time::Float64, ::Type{Val{1}}, ::Type{Val{true}})
props = problem.properties
field_dim = get_unknown_field_dimension(problem)
field_name = get_parent_field_name(problem)
slave_elements = get_slave_elements(problem)
if field_name != "displacement"
error("mortar forwarddiff assembly: only displacement field with adjust=yes supported")
end
function calculate_interface(x::Vector)
ndofs = round(Int, length(x)/2)
nnodes = round(Int, ndofs/field_dim)
u = reshape(x[1:ndofs], field_dim, nnodes)
la = reshape(x[ndofs+1:end], field_dim, nnodes)
fc = zeros(u)
gap = zeros(u)
C = zeros(la)
S = Set{Int64}()
# 1. update nodal normals for slave elements
tangents = zeros(u)
for element in slave_elements
conn = get_connectivity(element)
push!(S, conn...)
X1 = element("geometry", time)
u1 = Field([u[:,i] for i in conn])
x1 = X1 + u1
dN = get_dbasis(element, [0.0], time)
tangent = sum([kron(dN[:,i], x1[i]') for i=1:length(x1)])
for nid in conn
tangents[:,nid] += tangent[:]
end
end
Q = [0.0 -1.0; 1.0 0.0]
normals = zeros(u)
for j in S
tangents[:,j] /= norm(tangents[:,j])
normals[:,j] = Q*tangents[:,j]
end
if props.rotate_normals
for j in S
normals[:,j] = -normals[:,j]
end
end
#update!(slave_elements, "normal", time => Dict(j => normals[:,j] for j in S))
#update!(slave_elements, "tangent", time => Dict(j => tangents[:,j] for j in S))
# 2. loop all slave elements
for slave_element in slave_elements
nsl = length(slave_element)
slave_element_nodes = get_connectivity(slave_element)
X1 = slave_element["geometry"](time)
u1 = Field(Vector[u[:,i] for i in slave_element_nodes])
x1 = X1 + u1
la1 = Field(Vector[la[:,i] for i in slave_element_nodes])
n1 = Field(Vector[normals[:,i] for i in slave_element_nodes])
# 3. loop all master elements
for master_element in slave_element("master elements", time)
nm = length(master_element)
master_element_nodes = get_connectivity(master_element)
X2 = master_element("geometry", time)
u2 = Field(Vector[u[:,i] for i in master_element_nodes])
x2 = X2 + u2
# 3.1 calculate segmentation
xi1a = project_from_master_to_slave(slave_element, x1, n1, x2[1], time)
xi1b = project_from_master_to_slave(slave_element, x1, n1, x2[2], time)
# xi1a = project_from_master_to_slave(slave_element, X2[1], time)
# xi1b = project_from_master_to_slave(slave_element, X2[2], time)
xi1 = clamp.([xi1a; xi1b], -1.0, 1.0)
l = 1/2*abs(xi1[2]-xi1[1])
isapprox(l, 0.0) && continue # no contribution in this master element
# 3.2. bi-orthogonal basis
De = zeros(nsl, nsl)
Me = zeros(nsl, nsl)
Ae = zeros(nsl, nsl)
if props.dual_basis
for ip in get_integration_points(slave_element, 3)
detJ = slave_element(ip, time, Val{:detJ})
w = ip.weight*detJ*l
xi = ip.coords[1]
xi_s = dot([1/2*(1-xi); 1/2*(1+xi)], xi1)
N1 = vec(get_basis(slave_element, xi_s, time))
De += w*diagm(N1)
Me += w*N1*N1'
end
Ae = De*inv(Me)
else
Ae = eye(nsl)
end
# 3.3. loop integration points of one integration segment and calculate
# local mortar matrices
for ip in get_integration_points(slave_element, 3)
detJ = slave_element(ip, time, Val{:detJ})
w = ip.weight*detJ*l
#dN = get_dbasis(slave_element, ip, time)
#j = sum([kron(dN[:,i], x1[i]') for i=1:length(x1)])
#w = ip.weight*norm(j)*l
xi = ip.coords[1]
xi_s = dot([1/2*(1-xi); 1/2*(1+xi)], xi1)
N1 = vec(get_basis(slave_element, xi_s, time))
Phi = Ae*N1
# project gauss point from slave element to master element in direction n_s
x_s = N1*x1 # coordinate in gauss point
n_s = N1*n1 # normal direction in gauss point
#xi_m = project_from_slave_to_master(master_element, X_s, n_s, time)
xi_m = project_from_slave_to_master(master_element, x_s, n_s, x2, time)
N2 = vec(get_basis(master_element, xi_m, time))
x_m = N2*x2
la_s = Phi*la1
gn = dot(n_s, x_s-x_m)
u_s = N1*u1
u_m = N2*u2
X_s = N1*X1
X_m = N2*X2
fc[:,slave_element_nodes] += w*la_s*N1'
fc[:,master_element_nodes] -= w*la_s*N2'
#gap[1,slave_element_nodes] += w*gn*Phi'
gap[:,slave_element_nodes] += w*(u_s-u_m)*Phi'
if props.adjust
G = w*(X_s-X_m)*Phi'
gap[:,slave_element_nodes] += G
end
end
end # master elements done
end # slave elements done, contact virtual work ready
C = gap
return vec([fc C])
end
# x doesn't mean deformed configuration here
x = [problem.assembly.u; problem.assembly.la]
ndofs = round(Int, length(x)/2)
A = ForwardDiff.jacobian(calculate_interface, x)
b = -calculate_interface(x)
A = sparse(A)
b = sparse(b)
SparseArrays.droptol!(A, 1.0e-12)
SparseArrays.droptol!(b, 1.0e-12)
K = A[1:ndofs,1:ndofs]
C1 = transpose(A[1:ndofs,ndofs+1:end])
C2 = A[ndofs+1:end,1:ndofs]
D = A[ndofs+1:end,ndofs+1:end]
f = b[1:ndofs]
g = b[ndofs+1:end]
empty!(problem.assembly)
problem.assembly.K = K
problem.assembly.C1 = C1
problem.assembly.C2 = C2
problem.assembly.D = D
problem.assembly.f = f
problem.assembly.g = g
end