mirror of
https://github.com/JuliaFEM/JuliaFEM.jl.git
synced 2026-09-22 02:40:51 +00:00
Jukka Aho
102 lines
2.8 KiB
Julia
102 lines
2.8 KiB
Julia
"""
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calculate "local" normals in elements, in a way that
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n = Nᵢnᵢ gives some reasonable results for ξ ∈ [-1, 1]
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"""
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function calculate_normals!(el::Element, t, field_name=symbol("normals"))
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new_field!(el, field_name, Vector)
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for xi in Vector[[-1.0], [1.0]]
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t = dinterpolate(el, :Geometry, xi)
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n = [0 -1; 1 0]*t
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n /= norm(n)
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push_field!(el, field_name, n)
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end
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end
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"""
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Alter normal field such that normals of adjacent elements are averaged.
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"""
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function average_normals!(elements, normal_field=symbol("normals"))
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d = Dict()
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for el in elements
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c = get_connectivity(el)
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n = get_field(el, normal_field)
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for (ci, ni) in zip(c, n)
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d[ci] = haskey(d, ci) ? d[ci] + ni : ni
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end
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end
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for (ci, ni) in d
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d[ci] /= norm(d[ci])
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end
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for el in elements
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c = get_connectivity(el)
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new_normals = [d[ci] for ci in c]
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set_field(el, normal_field, new_normals)
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end
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end
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""" Find projection from slave nodes to master element. """
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function calc_projection_slave_nodes_to_master_element(sel, mel)
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X1 = get_field(sel, :Geometry)
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N1 = get_field(sel, :Normals)
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X2(xi) = interpolate(mel, :Geometry, xi)
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dX2(xi) = dinterpolate(mel, :Geometry, xi)
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R(xi, k) = det([X2(xi) - X1[k] N1[k]]')
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dR(xi, k) = det([dX2(xi) N1[k]]')
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xi2 = Vector[[0.0], [0.0]]
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for k=1:2
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xi = xi2[k]
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for i=1:3
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dxi = -R(xi, k)/dR(xi, k)
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xi += dxi
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if abs(dxi) < 1.0e-9
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break
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end
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end
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xi2[k] = xi
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end
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clamp!(xi2, -1, 1)
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return xi2
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end
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""" Find projection from master nodes to slave element. """
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function calc_projection_master_nodes_to_slave_element(sel, mel)
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X1(xi) = interpolate(sel, :Geometry, xi)
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dX1(xi) = dinterpolate(sel, :Geometry, xi)
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N1(xi) = interpolate(sel, :Normals, xi)
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dN1(xi) = dinterpolate(sel, :Normals, xi)
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X2 = get_field(mel, :Geometry)
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R(xi, k) = det([X1(xi) - X2[k] N1(xi)]')
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dR(xi, k) = det([dX1(xi) N1(xi)]') + det([X1(xi) - X2[k] dN1(xi)]')
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xi1 = Vector[[0.0], [0.0]]
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for k=1:2
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xi = xi1[k]
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for i=1:3
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dxi = -R(xi, k)/dR(xi, k)
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xi += dxi
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if abs(dxi) < 1.0e-9
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break
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end
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end
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xi1[k] = xi
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end
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clamp!(xi1, -1, 1)
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return xi1
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end
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function has_projection(sel, mel)
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xi1 = calc_projection_master_nodes_to_slave_element(sel, mel)
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l = abs(xi1[2]-xi1[1])[1]
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return l > 1.0e-9
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end
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"""
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Calculate projection between 1d boundary elements
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"""
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function calc_projection(sel, mel)
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xi1 = calc_projection_master_nodes_to_slave_element(sel, mel)
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xi2 = calc_projection_slave_nodes_to_master_element(sel, mel)
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return xi1, xi2
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end
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