mirror of
https://github.com/JuliaFEM/JuliaFEM.jl.git
synced 2026-09-20 18:18:31 +00:00
Jukka Aho
61 lines
1.9 KiB
Julia
61 lines
1.9 KiB
Julia
# This file is a part of JuliaFEM.
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# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE.md
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# Dirichlet boundary conditions in weak form
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abstract DirichletEquation <: Equation
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### Dirichlet problem + equations
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type DirichletProblem <: BoundaryProblem
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unknown_field_name :: ASCIIString
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unknown_field_dimension :: Int
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equations :: Array{DirichletEquation, 1}
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element_mapping :: Dict{DataType, DataType}
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field_value :: Function
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end
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function DirichletProblem(dimension::Int, field_value::Function=(X)->[0.0,0.0,0.0])
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element_mapping = nothing
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if dimension == 1
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element_mapping = Dict(
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Seg2 => DBC2D2
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)
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end
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DirichletProblem("reaction force", dimension, [], element_mapping, field_value)
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end
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""" Dirichlet boundary condition element for 2 node line segment """
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type DBC2D2 <: DirichletEquation
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element :: Seg2
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integration_points :: Array{IntegrationPoint, 1}
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end
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function DBC2D2(element::Seg2)
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integration_points = [
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IntegrationPoint([-sqrt(1/3)], 1.0),
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IntegrationPoint([+sqrt(1/3)], 1.0)]
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push!(element, FieldSet("reaction force"))
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DBC2D2(element, integration_points)
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end
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Base.size(equation::DBC2D2) = (1, 2)
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function calculate_local_assembly!(assembly::LocalAssembly, equation::DirichletEquation,
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unknown_field_name::ASCIIString, time::Number=Inf,
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problem=nothing)
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initialize_local_assembly!(assembly, equation)
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element = get_element(equation)
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basis = get_basis(element)
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detJ = det(basis)
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for ip in get_integration_points(equation)
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w = ip.weight * detJ(ip)
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N = basis(ip, time)
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assembly.stiffness_matrix += w * N'*N
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if !isa(problem, Void)
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X = basis("geometry", ip, time)
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u = problem.field_value(X)
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assembly.force_vector += w * N'*u
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end
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end
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end
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