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JuliaFEM.jl/test/test_von_mises_material.jl
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2015-12-10 16:58:23 +02:00

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module VonMisesTests
using PyPlot
using JuliaFEM.MaterialModels: stiffnessTensor, calculate_stress!, State
function test_von_mises_basic()
steps = 1000
strain_max = 0.003
num_cycles = 3
E = 200.0e3
nu = 0.3
ν = 0.3
C = stiffnessTensor(E, ν)
ϵ_tot = zeros(Float64, (steps, 6))
ϵ_tot2 = zeros(Float64, (steps, 6))
ϵ_tot3 = zeros(Float64, (steps, 6))
# Adding only strain in x-axis and counting for the poisson effect
ϵ_tot[:, 1] = strain_max * sin(2 * pi * linspace(0, num_cycles, steps))
ϵ_tot[:, 2] = strain_max * sin(2 * pi * linspace(0, num_cycles, steps)).*-ν
ϵ_tot[:, 3] = strain_max * sin(2 * pi * linspace(0, num_cycles, steps)).*-ν
ϵ_tot[:, 4] = strain_max / 10 * sin(2 * pi * linspace(0, num_cycles, steps))
ϵ_last = zeros(Float64, (6))
ϵᵖ = zeros(Float64, (6))
σ = zeros(Float64, (6, 1))
σy = 200.0
ss = Float64[]
ee = Float64[]
eig_stress = zeros(Float64, (3, 3))
eig_vals = zeros(Float64, (steps, 3))
function fill_tensor(a, b)
a[1, 1] = b[1]
a[2, 2] = b[2]
a[3, 3] = b[3]
a[1, 2] = b[6]
a[1, 3] = b[5]
a[2, 3] = b[4]
a[2, 1] = b[6]
a[3, 1] = b[5]
a[3, 2] = b[4]
end
mat = State(C, σy, zeros(Float64, 6), zeros(Float64, 6))
info("Starting calculation")
tic()
for i=1:steps
ϵ_new = reshape(ϵ_tot[i, :, :], (6, 1))
dϵ = ϵ_new - mat.ϵ
calculate_stress!(dϵ, mat, Val{:vonMises})
mat.ϵ += vec(dϵ)
push!(ss, mat.σ[1])
push!(ee, mat.ϵ[1])
fill_tensor(eig_stress, mat.σ)
eig_vals[i, :] = sort(eigvals(eig_stress))
end
toc()
# ================ Plotting =================== #
n(θ, ϕ) = [sin(θ)*cos(ϕ)
sin(θ)*sin(ϕ)
cos(θ)]
m(θ, ϕ, χ) = [-sin(ϕ)*cos(χ)-cos(θ)*cos(ϕ)*sin(χ)
cos(ϕ)*cos(χ)-cos(θ)*sin(ϕ)*sin(χ)
sin(θ)*sin(χ)]
w = [sqrt(2/3) * 200 * m(54.735 * pi / 180, 45 * pi/180, x) for x=0:0.15:(2*pi+0.1)]
base_vec = [1 1 1] / sqrt(3)
for i=-5:5
tt = [w[x] + vec(base_vec) + 50 * i for x=1:length(w)]
x = map(x->tt[x][1], collect(1:length(w)))
y = map(x->tt[x][2], collect(1:length(w)))
z = map(x->tt[x][3], collect(1:length(w)))
plot3D(x, y, z, color="blue")
end
tt = [w[x] + vec(base_vec) + 50 * -5 for x=1:length(w)]
x_start = map(x->tt[x][1], collect(1:length(w)))[1:5:end]
y_start = map(x->tt[x][2], collect(1:length(w)))[1:5:end]
z_start = map(x->tt[x][3], collect(1:length(w)))[1:5:end]
tt = [w[x] + vec(base_vec) + 50 * 5 for x=1:length(w)]
x_end = map(x->tt[x][1], collect(1:length(w)))[1:5:end]
y_end = map(x->tt[x][2], collect(1:length(w)))[1:5:end]
z_end = map(x->tt[x][3], collect(1:length(w)))[1:5:end]
for i=1:length(x_start)
x = [x_start[i], x_end[i]]
y = [y_start[i], y_end[i]]
z = [z_start[i], z_end[i]]
plot3D(x, y, z, color="blue")
end
info("Calculation finished")
#PyPlot.plot(ee, ss)
plot3D(eig_vals[:, 1], eig_vals[:, 2], eig_vals[:, 3], color="red")
PyPlot.title("Stress path and von Mises yield surface")
PyPlot.xlabel("Eig Stress 1")
PyPlot.ylabel("Eig Stress 2")
PyPlot.zlabel("Eig Stress 3")
PyPlot.grid()
PyPlot.show()
end
test_von_mises_basic()
end